chore(protocols): drop 43 no-op dead_code allows from swift

backlog#1823 step 8, partial. The swift module carries 43 #[allow(dead_code)] attributes, most with a comment naming a consumer: "Used by handler", "Handler integration: GET container", "Used by handler and object.rs". Every one of them suppresses nothing. crates/protocols/src/lib.rs declares `pub mod swift`, and swift/mod.rs declares all 22 submodules `pub mod`, so every item is publicly reachable and dead_code never applied to it. Removing all 43 leaves the warning count at zero, in both the default and --features swift lanes. That is also why those comments survived. They assert who calls the item — a claim the compiler normally settles on its own — and the compiler had been silenced by the visibility chain. The rest of step 8 needs a decision this PR does not make. Downgrading the 22 submodules to `pub(crate) mod` does restore detection, and it surfaces 39 real items, 16 of them the whole of sync.rs: SyncConfig, SyncStatus, SyncQueueEntry, ConflictResolution and every function and constant around them, i.e. Swift container sync is built and never wired. But the `pub mod` chain is load-bearing. Six integration tests under crates/protocols/tests are separate crates that import the submodules directly (swift::quota, swift::slo, swift::symlink, swift::sync, swift::tempurl, swift::container), and the downgrade fails to compile them. Restoring dead-code detection for this module therefore depends on first deciding whether those tests move in-crate — which is a testing-strategy call, not a cleanup one. Verification: cargo check -p rustfs-protocols warning-free in the default lane and with --features swift (lib and --tests); clippy --features swift --lib --tests -D warnings clean; cargo nextest run -p rustfs-protocols --features swift 441 passed; make pre-commit exit 0. Ref rustfs/backlog#1823 (step 8).
test(ecstore): add metadata slow-tail fault hook (#6150 )
2026-08-16 18:08:21 +00:00 · 2026-08-17 00:51:30 +08:00 · 2026-08-16 23:36:46 +08:00 · 2026-08-16 15:27:59 +00:00 · 2026-08-16 22:42:51 +08:00 · 2026-08-16 22:42:45 +08:00
285 changed files with 27580 additions and 6531 deletions
@@ -252,10 +252,16 @@ test-group = 'ecstore-serial-flaky'
 # cluster, so it keeps the lane's parallel-safe / no-external-dependency
 # properties. The RustFS warm backend has no loopback guard (that guard is
 # replication-only), so it needs no opt-in env for its 127.0.0.1 tier target.
+#
+# Disk compression (backlog#1848): the `compression` module joins the smoke
+# lane so the multipart disk-compression roundtrips (restored after
+# rustfs/rustfs#5169 disabled them) have PR-lane signal, not just merge-gate.
+# Single-node servers on random ports with isolated temp dirs — meets the
+# admission criteria unchanged.
 [profile.e2e-smoke]
 default-filter = """
    package(e2e_test) & (
-        test(/^(delete_marker_migration_semantics|version_id_regression|list_objects_v2_pagination|list_object_versions_regression|list_objects_duplicates|list_buckets_double_slash|list_buckets_auth|list_buckets_iam_filter|leading_slash_key|special_chars|create_bucket_region|delete_objects_versioning|head_object_consistency|head_object_range|copy_object_metadata|copy_object_tagging|copy_source_invalid_date|content_encoding|multipart_storage_class|storage_class_capability|ssec_copy|anonymous_access|bucket_policy_check|presigned_negative|negative_sigv4|admin_auth|notification_webhook|tls_hot_reload|console_smoke|admin_iam_crud|admin_pools|sts_query_compat)_test::|^fake_s3_target::/)
+        test(/^(delete_marker_migration_semantics|version_id_regression|list_objects_v2_pagination|list_object_versions_regression|list_objects_duplicates|list_buckets_double_slash|list_buckets_auth|list_buckets_iam_filter|leading_slash_key|special_chars|create_bucket_region|delete_objects_versioning|head_object_consistency|head_object_range|copy_object_metadata|copy_object_tagging|copy_source_invalid_date|content_encoding|compression|multipart_storage_class|storage_class_capability|ssec_copy|anonymous_access|bucket_policy_check|presigned_negative|negative_sigv4|admin_auth|notification_webhook|tls_hot_reload|console_smoke|admin_iam_crud|admin_pools|sts_query_compat)_test::|^fake_s3_target::/)
        | test(/^replication_extension_test::(test_replication_check_succeeds_with_remote_target|test_replication_check_rejects_target_without_object_lock|test_set_remote_target_rejects_unversioned_source_bucket|test_replication_check_rejects_unversioned_source_bucket|test_replication_check_rejects_missing_replication_config|test_replication_check_rejects_invalid_bucket|test_set_remote_target_rejects_same_bucket_on_same_deployment|test_set_remote_target_rejects_unversioned_target_bucket|test_set_remote_target_update_requires_arn|test_set_remote_target_update_rejects_missing_target|test_set_remote_target_rejects_invalid_target_url|test_set_remote_target_rejects_self_signed_https_target_without_skip_tls_verify|test_set_remote_target_rejects_private_ca_https_target_without_ca_cert_pem|test_list_remote_targets_rejects_empty_bucket|test_list_remote_targets_rejects_invalid_bucket|test_remove_remote_target_rejects_missing_target|test_remove_remote_target_rejects_missing_arn|test_remove_remote_target_rejects_invalid_bucket|test_remove_remote_target_rejects_target_used_by_replication|test_delete_bucket_replication_removes_remote_target)$/)
        | test(/^reliant::lifecycle::/)
        | test(/^reliant::tiering::/)
@@ -182,7 +182,12 @@ jobs:
            echo '```'
          } >> "$GITHUB_STEP_SUMMARY"

-  # Readers: test-and-lint-rio-v2, build-rustfs-debug-binary-rio-v2.
+  # Readers: test-and-lint-rio-v2 (per-PR), build-rustfs-debug-binary-rio-v2
+  # (weekly schedule / manual dispatch only — dormant rio-v2 variant, see
+  # rustfs/backlog#1835 and docs/architecture/minio-file-format-compat.md).
+  # The second build below stays despite the reduced cadence: it warms the
+  # rio-v2,e2e-test-hooks feature resolution the scheduled build restores,
+  # which keeps that lane inside its 30-minute timeout.
  warm-ci-feat-rio:
    name: Warm ci-feat-rio
    runs-on: sm-standard-4
@@ -533,7 +533,12 @@ jobs:

  build-rustfs-debug-binary-rio-v2:
    name: Build RustFS Debug Binary (rio-v2)
-    if: github.event_name != 'pull_request' || github.event.action != 'closed'
+    # Dormant rio-v2 variant (rustfs/backlog#1835): the feature ships in no
+    # default build, so this full-suite lane runs only on the weekly schedule
+    # and manual dispatch. Per-PR cfg-seam coverage stays with
+    # test-and-lint-rio-v2. Lifecycle and the promote-or-delete condition:
+    # docs/architecture/minio-file-format-compat.md ("rio-v2 variant lifecycle").
+    if: github.event_name == 'schedule' || github.event_name == 'workflow_dispatch'
    needs: [ quick-checks ]
    runs-on: sm-standard-4
    timeout-minutes: 30
@@ -824,6 +829,9 @@ jobs:

  e2e-tests-rio-v2:
    name: End-to-End Tests (rio-v2)
+    # Inherits the schedule/dispatch-only gate through needs: on every other
+    # event build-rustfs-debug-binary-rio-v2 is skipped, so this job skips
+    # with it (see the dormant-variant comment on that job).
    needs: [ build-rustfs-debug-binary-rio-v2 ]
    runs-on: sm-standard-2
    timeout-minutes: 30
@@ -94,6 +94,7 @@ jobs:
      short_sha: ${{ steps.check.outputs.short_sha }}
      is_prerelease: ${{ steps.check.outputs.is_prerelease }}
      create_latest: ${{ steps.check.outputs.create_latest }}
+      source_ref: ${{ steps.check.outputs.source_ref }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
@@ -118,6 +119,7 @@ jobs:
          short_sha=""
          is_prerelease=false
          create_latest=false
+          source_ref="$GITHUB_SHA"

          if [[ "${{ github.event_name }}" == "workflow_run" ]]; then
            # Triggered by build workflow completion
@@ -137,6 +139,7 @@ jobs:
            # Extract version info from commit message or use commit SHA
            # Use Git to generate consistent short SHA (ensures uniqueness like build.yml)
            short_sha=$(git rev-parse --short "$HEAD_SHA")
+            source_ref="$HEAD_SHA"

            # Determine build type based on triggering workflow event and ref
            triggering_event="$TRIGGERING_EVENT"
@@ -261,6 +264,23 @@ jobs:
                echo "⚠️  Only release versions (latest, v1.0.0, 1.0.0) and prereleases (v1.0.0-alpha1, 1.0.0-beta2) are supported"
                ;;
            esac
+
+            if [[ "$should_build" == true && "$input_version" != "latest" ]]; then
+              tag_ref="refs/tags/$input_version"
+              if ! git ls-remote --exit-code origin "$tag_ref" >/dev/null 2>&1; then
+                if [[ "$input_version" == v* ]]; then
+                  tag_ref="refs/tags/${input_version#v}"
+                else
+                  tag_ref="refs/tags/v$input_version"
+                fi
+              fi
+
+              if ! git ls-remote --exit-code origin "$tag_ref" >/dev/null 2>&1; then
+                echo "❌ Release tag not found for Docker build: $input_version"
+                exit 1
+              fi
+              source_ref="$tag_ref"
+            fi
          fi

          {
@@ -271,6 +291,7 @@ jobs:
            echo "short_sha=$short_sha"
            echo "is_prerelease=$is_prerelease"
            echo "create_latest=$create_latest"
+            echo "source_ref=$source_ref"
          } >> "$GITHUB_OUTPUT"

          echo "🐳 Docker Build Summary:"
@@ -281,6 +302,7 @@ jobs:
          echo "  - Short SHA: $short_sha"
          echo "  - Is prerelease: $is_prerelease"
          echo "  - Create latest: $create_latest"
+          echo "  - Source ref: $source_ref"

  # Build multi-arch Docker images
  # Strategy: Build images using pre-built binaries from dl.rustfs.com
@@ -308,6 +330,7 @@ jobs:
        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
        with:
          persist-credentials: false
+          ref: ${{ needs.build-check.outputs.source_ref }}

      - name: Login to Docker Hub
        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3
@@ -397,7 +420,8 @@ jobs:
          LABELS="org.opencontainers.image.title=RustFS"
          LABELS="$LABELS,org.opencontainers.image.description=RustFS distributed object storage system"
          LABELS="$LABELS,org.opencontainers.image.version=$VERSION"
-          LABELS="$LABELS,org.opencontainers.image.revision=${{ github.sha }}"
+          SOURCE_REVISION="$(git rev-parse HEAD)"
+          LABELS="$LABELS,org.opencontainers.image.revision=$SOURCE_REVISION"
          LABELS="$LABELS,org.opencontainers.image.source=${{ github.server_url }}/${{ github.repository }}"
          LABELS="$LABELS,org.opencontainers.image.created=$(date -u +'%Y-%m-%dT%H:%M:%SZ')"
          LABELS="$LABELS,org.opencontainers.image.build-type=$BUILD_TYPE"
@@ -101,7 +101,10 @@ refactors.

 The `rustfs` binary crate composes these libraries into the running server.
 `ecstore` remains the storage engine at the architectural center; its internal
-module split is tracked under `docs/architecture/`.
+module split is tracked under `docs/architecture/`. `rio-v2` is the
+feature-gated MinIO on-disk format compatibility I/O layer; it ships in no
+default build (lifecycle:
+[docs/architecture/minio-file-format-compat.md](docs/architecture/minio-file-format-compat.md)).

 ## Architecture Invariants

@@ -278,6 +278,7 @@ checksum = "312c1ea69e5fe9966e0029fb95aca8790100b85aff4f0d3b00a9337c74069a9c"
 dependencies = [
 "bigdecimal",
 "bon",
+ "crc32fast",
 "digest 0.11.3",
 "log",
 "miniz_oxide 0.9.1",
@@ -289,9 +290,11 @@ dependencies = [
 "serde",
 "serde_bytes",
 "serde_json",
+ "snap",
 "strum",
 "thiserror 2.0.20",
 "uuid",
+ "zstd",
 ]

 [[package]]
@@ -3761,7 +3764,7 @@ checksum = "d0881ea181b1df73ff77ffaaf9c7544ecc11e82fba9b5f27b262a3c73a332555"

 [[package]]
 name = "e2e_test"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "anyhow",
 "astral-tokio-tar",
@@ -9090,7 +9093,7 @@ dependencies = [

 [[package]]
 name = "rustfs"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "aes-gcm",
 "anyhow",
@@ -9200,6 +9203,7 @@ dependencies = [
 "serial_test",
 "sha2 0.11.0",
 "shadow-rs",
+ "snap",
 "socket2",
 "subtle",
 "sysinfo",
@@ -9227,7 +9231,7 @@ dependencies = [

 [[package]]
 name = "rustfs-audit"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-trait",
 "const-str",
@@ -9250,7 +9254,7 @@ dependencies = [

 [[package]]
 name = "rustfs-checksums"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "base64-simd",
 "bytes",
@@ -9266,7 +9270,7 @@ dependencies = [

 [[package]]
 name = "rustfs-common"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "chrono",
 "hotpath",
@@ -9284,7 +9288,7 @@ dependencies = [

 [[package]]
 name = "rustfs-concurrency"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "hotpath",
 "insta",
@@ -9297,7 +9301,7 @@ dependencies = [

 [[package]]
 name = "rustfs-config"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "const-str",
 "hotpath",
@@ -9307,7 +9311,7 @@ dependencies = [

 [[package]]
 name = "rustfs-credentials"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "base64-simd",
 "hmac 0.13.0",
@@ -9321,7 +9325,7 @@ dependencies = [

 [[package]]
 name = "rustfs-crypto"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "aes-gcm",
 "argon2",
@@ -9342,7 +9346,7 @@ dependencies = [

 [[package]]
 name = "rustfs-data-usage"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "hotpath",
 "rmp-serde",
@@ -9352,7 +9356,7 @@ dependencies = [

 [[package]]
 name = "rustfs-ecstore"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "arc-swap",
 "async-channel",
@@ -9491,7 +9495,7 @@ dependencies = [

 [[package]]
 name = "rustfs-extension-schema"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "hotpath",
 "serde",
@@ -9501,7 +9505,7 @@ dependencies = [

 [[package]]
 name = "rustfs-filemeta"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "arc-swap",
 "byteorder",
@@ -9528,7 +9532,7 @@ dependencies = [

 [[package]]
 name = "rustfs-heal"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-trait",
 "base64 0.23.1",
@@ -9559,7 +9563,7 @@ dependencies = [

 [[package]]
 name = "rustfs-iam"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "arc-swap",
 "async-trait",
@@ -9600,7 +9604,7 @@ dependencies = [

 [[package]]
 name = "rustfs-io-core"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "bytes",
 "hotpath",
@@ -9613,7 +9617,7 @@ dependencies = [

 [[package]]
 name = "rustfs-io-metrics"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "criterion",
 "hotpath",
@@ -9677,7 +9681,7 @@ dependencies = [

 [[package]]
 name = "rustfs-keystone"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "bytes",
 "futures",
@@ -9704,7 +9708,7 @@ dependencies = [

 [[package]]
 name = "rustfs-kms"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "aes-gcm",
 "anyhow",
@@ -9753,7 +9757,7 @@ dependencies = [

 [[package]]
 name = "rustfs-lifecycle"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-trait",
 "hotpath",
@@ -9776,7 +9780,7 @@ dependencies = [

 [[package]]
 name = "rustfs-lock"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-trait",
 "compact_str",
@@ -9799,7 +9803,7 @@ dependencies = [

 [[package]]
 name = "rustfs-log-analyzer"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "chrono",
 "flate2",
@@ -9818,7 +9822,7 @@ dependencies = [

 [[package]]
 name = "rustfs-madmin"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "hotpath",
 "humantime",
@@ -9833,7 +9837,7 @@ dependencies = [

 [[package]]
 name = "rustfs-notify"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "arc-swap",
 "async-trait",
@@ -9868,7 +9872,7 @@ dependencies = [

 [[package]]
 name = "rustfs-object-capacity"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "criterion",
 "futures",
@@ -9888,7 +9892,7 @@ dependencies = [

 [[package]]
 name = "rustfs-object-data-cache"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "bytes",
 "criterion",
@@ -9905,7 +9909,7 @@ dependencies = [

 [[package]]
 name = "rustfs-obs"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "chrono",
 "crossbeam-channel",
@@ -9960,7 +9964,7 @@ dependencies = [

 [[package]]
 name = "rustfs-policy"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-trait",
 "base64-simd",
@@ -9991,7 +9995,7 @@ dependencies = [

 [[package]]
 name = "rustfs-protocols"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "astral-tokio-tar",
 "async-compression",
@@ -10053,7 +10057,7 @@ dependencies = [

 [[package]]
 name = "rustfs-protos"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "flatbuffers",
 "hotpath",
@@ -10077,7 +10081,7 @@ dependencies = [

 [[package]]
 name = "rustfs-replication"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "byteorder",
 "bytes",
@@ -10095,7 +10099,7 @@ dependencies = [

 [[package]]
 name = "rustfs-rio"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "aes-gcm",
 "arc-swap",
@@ -10133,7 +10137,7 @@ dependencies = [

 [[package]]
 name = "rustfs-rio-v2"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "aes-gcm",
 "bytes",
@@ -10156,7 +10160,7 @@ dependencies = [

 [[package]]
 name = "rustfs-s3-ops"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "hotpath",
 "rustfs-s3-types",
@@ -10164,7 +10168,7 @@ dependencies = [

 [[package]]
 name = "rustfs-s3-types"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "hotpath",
 "serde",
@@ -10173,7 +10177,7 @@ dependencies = [

 [[package]]
 name = "rustfs-s3select-api"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-trait",
 "bytes",
@@ -10203,7 +10207,7 @@ dependencies = [

 [[package]]
 name = "rustfs-s3select-query"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-recursion",
 "async-trait",
@@ -10222,7 +10226,7 @@ dependencies = [

 [[package]]
 name = "rustfs-scanner"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-trait",
 "bytes",
@@ -10262,7 +10266,7 @@ dependencies = [

 [[package]]
 name = "rustfs-security-governance"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "hotpath",
 "thiserror 2.0.20",
@@ -10270,7 +10274,7 @@ dependencies = [

 [[package]]
 name = "rustfs-signer"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "base64-simd",
 "bytes",
@@ -10288,7 +10292,7 @@ dependencies = [

 [[package]]
 name = "rustfs-storage-api"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-trait",
 "hotpath",
@@ -10303,7 +10307,7 @@ dependencies = [

 [[package]]
 name = "rustfs-targets"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "arc-swap",
 "async-nats",
@@ -10357,7 +10361,7 @@ dependencies = [

 [[package]]
 name = "rustfs-test-utils"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "hotpath",
 "rustfs-data-usage",
@@ -10373,7 +10377,7 @@ dependencies = [

 [[package]]
 name = "rustfs-tls-runtime"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "arc-swap",
 "hotpath",
@@ -10394,7 +10398,7 @@ dependencies = [

 [[package]]
 name = "rustfs-trusted-proxies"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "async-trait",
 "axum",
@@ -10431,7 +10435,7 @@ dependencies = [

 [[package]]
 name = "rustfs-utils"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "base64-simd",
 "blake2",
@@ -10473,7 +10477,7 @@ dependencies = [

 [[package]]
 name = "rustfs-zip"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 dependencies = [
 "astral-tokio-tar",
 "async-compression",
@@ -41,7 +41,7 @@ members = [
    "crates/protocols", # Protocol implementations (FTPS, SFTP, etc.)
    "crates/protos", # Protocol buffer definitions
    "crates/rio", # Rust I/O utilities and abstractions
-    "crates/rio-v2", # Next-generation Rust I/O compatibility layer
+    "crates/rio-v2", # MinIO on-disk format compatibility I/O layer (feature-gated, ships in no default build)
    "crates/replication", # Replication contracts and wire formats
    "crates/concurrency", # Concurrency management for RustFS - timeout, locking, backpressure, and I/O scheduling
    "crates/s3-types", # S3 event type definitions
@@ -69,7 +69,7 @@ edition = "2024"
 license = "Apache-2.0"
 repository = "https://github.com/rustfs/rustfs"
 rust-version = "1.97.1"
-version = "1.0.0-rc.1"
+version = "1.0.0-rc.2"
 homepage = "https://rustfs.com"
 description = "RustFS is a high-performance distributed object storage software built using Rust, one of the most popular languages worldwide. "
 keywords = ["RustFS", "Minio", "object-storage", "filesystem", "s3"]
@@ -86,52 +86,52 @@ redundant_clone = "warn"

 [workspace.dependencies]
 # RustFS Internal Crates
-rustfs = { path = "./rustfs", version = "1.0.0-rc.1" }
-rustfs-heal = { path = "crates/heal", version = "1.0.0-rc.1" }
-rustfs-audit = { path = "crates/audit", version = "1.0.0-rc.1" }
-rustfs-checksums = { path = "crates/checksums", version = "1.0.0-rc.1" }
-rustfs-common = { path = "crates/common", version = "1.0.0-rc.1" }
-rustfs-data-usage = { path = "crates/data-usage", version = "1.0.0-rc.1" }
-rustfs-config = { path = "./crates/config", version = "1.0.0-rc.1" }
-rustfs-concurrency = { path = "./crates/concurrency", version = "1.0.0-rc.1" }
-rustfs-credentials = { path = "crates/credentials", version = "1.0.0-rc.1" }
-rustfs-crypto = { path = "crates/crypto", version = "1.0.0-rc.1" }
-rustfs-ecstore = { path = "crates/ecstore", version = "1.0.0-rc.1" }
-rustfs-filemeta = { path = "crates/filemeta", version = "1.0.0-rc.1" }
-rustfs-iam = { path = "crates/iam", version = "1.0.0-rc.1" }
-rustfs-keystone = { path = "crates/keystone", version = "1.0.0-rc.1" }
-rustfs-lifecycle = { path = "crates/lifecycle", version = "1.0.0-rc.1" }
-rustfs-kms = { path = "crates/kms", version = "1.0.0-rc.1" }
-rustfs-lock = { path = "crates/lock", version = "1.0.0-rc.1" }
-rustfs-madmin = { path = "crates/madmin", version = "1.0.0-rc.1" }
-rustfs-notify = { path = "crates/notify", version = "1.0.0-rc.1" }
-rustfs-io-metrics = { path = "crates/io-metrics", version = "1.0.0-rc.1" }
-rustfs-io-core = { path = "crates/io-core", version = "1.0.0-rc.1" }
-rustfs-object-capacity = { path = "crates/object-capacity", version = "1.0.0-rc.1" }
-rustfs-object-data-cache = { path = "crates/object-data-cache", version = "1.0.0-rc.1", default-features = false }
-rustfs-log-analyzer = { path = "crates/log-analyzer", version = "1.0.0-rc.1" }
-rustfs-obs = { path = "crates/obs", version = "1.0.0-rc.1" }
-rustfs-policy = { path = "crates/policy", version = "1.0.0-rc.1" }
-rustfs-protos = { path = "crates/protos", version = "1.0.0-rc.1" }
-rustfs-protocols = { path = "crates/protocols", version = "1.0.0-rc.1" }
-rustfs-replication = { path = "crates/replication", version = "1.0.0-rc.1" }
-rustfs-rio = { path = "crates/rio", version = "1.0.0-rc.1" }
-rustfs-rio-v2 = { path = "crates/rio-v2", version = "1.0.0-rc.1" }
-rustfs-s3-types = { path = "crates/s3-types", version = "1.0.0-rc.1" }
-rustfs-s3-ops = { path = "crates/s3-ops", version = "1.0.0-rc.1" }
-rustfs-s3select-api = { path = "crates/s3select-api", version = "1.0.0-rc.1" }
-rustfs-s3select-query = { path = "crates/s3select-query", version = "1.0.0-rc.1" }
-rustfs-scanner = { path = "crates/scanner", version = "1.0.0-rc.1" }
-rustfs-security-governance = { path = "crates/security-governance", version = "1.0.0-rc.1" }
-rustfs-extension-schema = { path = "crates/extension-schema", version = "1.0.0-rc.1" }
-rustfs-signer = { path = "crates/signer", version = "1.0.0-rc.1" }
-rustfs-storage-api = { path = "crates/storage-api", version = "1.0.0-rc.1" }
-rustfs-trusted-proxies = { path = "crates/trusted-proxies", version = "1.0.0-rc.1" }
-rustfs-targets = { path = "crates/targets", version = "1.0.0-rc.1" }
-rustfs-test-utils = { path = "crates/test-utils", version = "1.0.0-rc.1" }
-rustfs-tls-runtime = { path = "crates/tls-runtime", version = "1.0.0-rc.1" }
-rustfs-utils = { path = "crates/utils", version = "1.0.0-rc.1" }
-rustfs-zip = { path = "./crates/zip", version = "1.0.0-rc.1" }
+rustfs = { path = "./rustfs", version = "1.0.0-rc.2" }
+rustfs-heal = { path = "crates/heal", version = "1.0.0-rc.2" }
+rustfs-audit = { path = "crates/audit", version = "1.0.0-rc.2" }
+rustfs-checksums = { path = "crates/checksums", version = "1.0.0-rc.2" }
+rustfs-common = { path = "crates/common", version = "1.0.0-rc.2" }
+rustfs-data-usage = { path = "crates/data-usage", version = "1.0.0-rc.2" }
+rustfs-config = { path = "./crates/config", version = "1.0.0-rc.2" }
+rustfs-concurrency = { path = "./crates/concurrency", version = "1.0.0-rc.2" }
+rustfs-credentials = { path = "crates/credentials", version = "1.0.0-rc.2" }
+rustfs-crypto = { path = "crates/crypto", version = "1.0.0-rc.2" }
+rustfs-ecstore = { path = "crates/ecstore", version = "1.0.0-rc.2" }
+rustfs-filemeta = { path = "crates/filemeta", version = "1.0.0-rc.2" }
+rustfs-iam = { path = "crates/iam", version = "1.0.0-rc.2" }
+rustfs-keystone = { path = "crates/keystone", version = "1.0.0-rc.2" }
+rustfs-lifecycle = { path = "crates/lifecycle", version = "1.0.0-rc.2" }
+rustfs-kms = { path = "crates/kms", version = "1.0.0-rc.2" }
+rustfs-lock = { path = "crates/lock", version = "1.0.0-rc.2" }
+rustfs-madmin = { path = "crates/madmin", version = "1.0.0-rc.2" }
+rustfs-notify = { path = "crates/notify", version = "1.0.0-rc.2" }
+rustfs-io-metrics = { path = "crates/io-metrics", version = "1.0.0-rc.2" }
+rustfs-io-core = { path = "crates/io-core", version = "1.0.0-rc.2" }
+rustfs-object-capacity = { path = "crates/object-capacity", version = "1.0.0-rc.2" }
+rustfs-object-data-cache = { path = "crates/object-data-cache", version = "1.0.0-rc.2", default-features = false }
+rustfs-log-analyzer = { path = "crates/log-analyzer", version = "1.0.0-rc.2" }
+rustfs-obs = { path = "crates/obs", version = "1.0.0-rc.2" }
+rustfs-policy = { path = "crates/policy", version = "1.0.0-rc.2" }
+rustfs-protos = { path = "crates/protos", version = "1.0.0-rc.2" }
+rustfs-protocols = { path = "crates/protocols", version = "1.0.0-rc.2" }
+rustfs-replication = { path = "crates/replication", version = "1.0.0-rc.2" }
+rustfs-rio = { path = "crates/rio", version = "1.0.0-rc.2" }
+rustfs-rio-v2 = { path = "crates/rio-v2", version = "1.0.0-rc.2" }
+rustfs-s3-types = { path = "crates/s3-types", version = "1.0.0-rc.2" }
+rustfs-s3-ops = { path = "crates/s3-ops", version = "1.0.0-rc.2" }
+rustfs-s3select-api = { path = "crates/s3select-api", version = "1.0.0-rc.2" }
+rustfs-s3select-query = { path = "crates/s3select-query", version = "1.0.0-rc.2" }
+rustfs-scanner = { path = "crates/scanner", version = "1.0.0-rc.2" }
+rustfs-security-governance = { path = "crates/security-governance", version = "1.0.0-rc.2" }
+rustfs-extension-schema = { path = "crates/extension-schema", version = "1.0.0-rc.2" }
+rustfs-signer = { path = "crates/signer", version = "1.0.0-rc.2" }
+rustfs-storage-api = { path = "crates/storage-api", version = "1.0.0-rc.2" }
+rustfs-trusted-proxies = { path = "crates/trusted-proxies", version = "1.0.0-rc.2" }
+rustfs-targets = { path = "crates/targets", version = "1.0.0-rc.2" }
+rustfs-test-utils = { path = "crates/test-utils", version = "1.0.0-rc.2" }
+rustfs-tls-runtime = { path = "crates/tls-runtime", version = "1.0.0-rc.2" }
+rustfs-utils = { path = "crates/utils", version = "1.0.0-rc.2" }
+rustfs-zip = { path = "./crates/zip", version = "1.0.0-rc.2" }

 # Async Runtime and Networking
 async-channel = "2.5.0"
@@ -171,7 +171,7 @@ tower = { version = "0.5.3" }
 tower-http = { version = "0.7.0" }

 # Serialization and Data Formats
-apache-avro = "0.22.0"
+apache-avro = { version = "0.22.0", features = ["snappy", "zstandard"] }
 bytes = { version = "1.12.1" }
 bytesize = "2.7.0"
 byteorder = "1.5.0"
@@ -116,7 +116,7 @@ chown -R 10001:10001 data logs
 docker run -d -p 9000:9000 -p 9001:9001 -v $(pwd)/data:/data -v $(pwd)/logs:/logs rustfs/rustfs:latest

 # Using specific version
-docker run -d -p 9000:9000 -p 9001:9001 -v $(pwd)/data:/data -v $(pwd)/logs:/logs rustfs/rustfs:1.0.0-rc.1
+docker run -d -p 9000:9000 -p 9001:9001 -v $(pwd)/data:/data -v $(pwd)/logs:/logs rustfs/rustfs:1.0.0-rc.2
 ```

 If you use [podman](https://github.com/containers/podman) instead of docker, you can install the RustFS with the below command
@@ -113,7 +113,7 @@ chown -R 10001:10001 data logs
 docker run -d -p 9000:9000 -p 9001:9001 -v $(pwd)/data:/data -v $(pwd)/logs:/logs rustfs/rustfs:latest

 # 使用指定版本运行
-docker run -d -p 9000:9000 -p 9001:9001 -v $(pwd)/data:/data -v $(pwd)/logs:/logs rustfs/rustfs:1.0.0-rc.1
+docker run -d -p 9000:9000 -p 9001:9001 -v $(pwd)/data:/data -v $(pwd)/logs:/logs rustfs/rustfs:1.0.0-rc.2
 ```

 如果您通过绑定挂载启用 TLS 证书目录，也请用同样方式准备该目录：
@@ -11,7 +11,6 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-#![allow(dead_code)]

 use base64_simd::STANDARD;

@@ -137,6 +137,22 @@ pub const DEFAULT_TIER_REMOTE_VERSION_STATE_FLEET_CONFIRMED: bool = false;
 const _: () = assert!(!DEFAULT_TIER_REMOTE_VERSION_STATE_WRITE);
 const _: () = assert!(!DEFAULT_TIER_REMOTE_VERSION_STATE_FLEET_CONFIRMED);

+/// Request the object-transaction fencing contract used by storage-owned
+/// cleanup receipts and lock-window optimizations.
+///
+/// This is fail-closed: enabling the writer without a live fleet proof rejects
+/// the commit rather than silently using a legacy-safe path.
+pub const ENV_OBJECT_TRANSACTION_FENCING_WRITE: &str = "RUSTFS_OBJECT_TRANSACTION_FENCING_WRITE";
+pub const DEFAULT_OBJECT_TRANSACTION_FENCING_WRITE: bool = false;
+
+/// Operator-attested confirmation that every serving node understands the
+/// object transaction fencing contract.
+pub const ENV_OBJECT_TRANSACTION_FENCING_FLEET_CONFIRMED: &str = "RUSTFS_OBJECT_TRANSACTION_FENCING_FLEET_CONFIRMED";
+pub const DEFAULT_OBJECT_TRANSACTION_FENCING_FLEET_CONFIRMED: bool = false;
+
+const _: () = assert!(!DEFAULT_OBJECT_TRANSACTION_FENCING_WRITE);
+const _: () = assert!(!DEFAULT_OBJECT_TRANSACTION_FENCING_FLEET_CONFIRMED);
+
 /// Request preserving legacy per-part checksum metadata during data movement.
 ///
 /// This remains ineffective until
@@ -673,4 +689,13 @@ mod remote_version_state_tests {
            "RUSTFS_DATA_MOVEMENT_PART_CHECKSUMS_FLEET_CONFIRMED"
        );
    }
+
+    #[test]
+    fn object_transaction_fencing_gate_uses_stable_environment_names() {
+        assert_eq!(super::ENV_OBJECT_TRANSACTION_FENCING_WRITE, "RUSTFS_OBJECT_TRANSACTION_FENCING_WRITE");
+        assert_eq!(
+            super::ENV_OBJECT_TRANSACTION_FENCING_FLEET_CONFIRMED,
+            "RUSTFS_OBJECT_TRANSACTION_FENCING_FLEET_CONFIRMED"
+        );
+    }
 }
@@ -67,7 +67,10 @@ fn configured_capture_log_path(temp_dir: &str) -> Option<String> {
    capture_log_path(Path::new(&log_dir), temp_dir).map(|path| path.to_string_lossy().into_owned())
 }

-fn capture_command_logs(command: &mut Command, log_path: Option<&str>) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+pub(crate) fn capture_command_logs(
+    command: &mut Command,
+    log_path: Option<&str>,
+) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
    let Some(log_path) = log_path else {
        return Ok(());
    };
@@ -2,6 +2,7 @@

 use crate::common::{RustFSTestEnvironment, init_logging, rustfs_binary_path};
 use aws_sdk_s3::primitives::ByteStream;
+use aws_sdk_s3::types::{CompletedMultipartUpload, CompletedPart};
 use serial_test::serial;
 use std::fs;
 use std::path::PathBuf;
@@ -25,6 +26,15 @@ fn generate_compressible_data(size: usize) -> Vec<u8> {
    data
 }

+/// Deterministic 2048-byte-period binary pattern that compresses extremely well: every part
+/// yields many compressed blocks, which is exactly the shape that reproduced the mid-payload
+/// Pending truncation (rustfs/rustfs#5957).
+fn generate_high_ratio_binary_data(size: usize, seed: u8) -> Vec<u8> {
+    (0..size)
+        .map(|i| ((i as u64).wrapping_mul(2_654_435_761).wrapping_add(seed as u64) >> 3) as u8)
+        .collect()
+}
+
 fn find_part_files(temp_dir: &str, bucket: &str, object_key: &str) -> Vec<PathBuf> {
    let bucket_path = PathBuf::from(temp_dir).join(bucket);
    let mut part_files = Vec::new();
@@ -55,9 +65,14 @@ async fn start_rustfs_with_compression(env: &mut RustFSTestEnvironment) -> Resul
    env.cleanup_existing_processes().await?;

    let binary_path = rustfs_binary_path();
-    let process = Command::new(&binary_path)
+    // Route the child's stdout/stderr through the shared RUSTFS_E2E_LOG_DIR
+    // capture (survives the temp-dir cleanup on Drop and is uploaded as a CI
+    // artifact); without the env var the child inherits stdio as before.
+    let mut command = Command::new(&binary_path);
+    command
        .env("RUSTFS_CONSOLE_ENABLE", "false")
        .env("RUSTFS_COMPRESSION_ENABLED", "true")
+        .env("RUSTFS_COMPRESSION_MULTIPART_ENABLED", "true")
        .args([
            "--address",
            &env.address,
@@ -66,8 +81,9 @@ async fn start_rustfs_with_compression(env: &mut RustFSTestEnvironment) -> Resul
            "--secret-key",
            &env.secret_key,
            &env.temp_dir,
-        ])
-        .spawn()?;
+        ]);
+    crate::common::capture_command_logs(&mut command, env.capture_log_path.as_deref())?;
+    let process = command.spawn()?;

    env.process = Some(process);

@@ -154,3 +170,647 @@ async fn test_compression_roundtrip() -> Result<(), Box<dyn std::error::Error +
    env.stop_server();
    Ok(())
 }
+
+const MULTIPART_COMPRESSION_BUCKET: &str = "compression-multipart-bucket";
+const MPU_PART1_SIZE: usize = 5 * 1024 * 1024;
+const MPU_PART2_SIZE: usize = 1024 * 1024;
+
+async fn multipart_upload(
+    client: &aws_sdk_s3::Client,
+    bucket: &str,
+    key: &str,
+    parts: &[&[u8]],
+) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    let create = client.create_multipart_upload().bucket(bucket).key(key).send().await?;
+    let upload_id = create.upload_id().ok_or("missing upload id")?.to_string();
+
+    let mut completed_parts = Vec::with_capacity(parts.len());
+    for (i, part) in parts.iter().enumerate() {
+        let part_number = (i + 1) as i32;
+        let upload = client
+            .upload_part()
+            .bucket(bucket)
+            .key(key)
+            .upload_id(&upload_id)
+            .part_number(part_number)
+            .body(ByteStream::from(part.to_vec()))
+            .send()
+            .await?;
+        completed_parts.push(
+            CompletedPart::builder()
+                .part_number(part_number)
+                .e_tag(upload.e_tag().unwrap_or_default())
+                .build(),
+        );
+    }
+
+    client
+        .complete_multipart_upload()
+        .bucket(bucket)
+        .key(key)
+        .upload_id(&upload_id)
+        .multipart_upload(CompletedMultipartUpload::builder().set_parts(Some(completed_parts)).build())
+        .send()
+        .await?;
+    Ok(())
+}
+
+async fn fetch_range(
+    client: &aws_sdk_s3::Client,
+    bucket: &str,
+    key: &str,
+    range: &str,
+) -> Result<Vec<u8>, Box<dyn std::error::Error + Send + Sync>> {
+    let response = client.get_object().bucket(bucket).key(key).range(range).send().await?;
+    Ok(response.body.collect().await?.into_bytes().to_vec())
+}
+
+/// Multipart disk compression roundtrip: parts are written as independent
+/// compressed streams and every GET shape must reassemble the original bytes
+/// (rustfs/rustfs#5957: multipart uploads previously bypassed disk compression
+/// entirely).
+#[tokio::test]
+#[serial]
+async fn test_compression_multipart_roundtrip() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    init_logging();
+    info!("Starting multipart compression roundtrip test");
+
+    let mut env = RustFSTestEnvironment::new().await?;
+    start_rustfs_with_compression(&mut env).await?;
+
+    let client = env.create_s3_client();
+    env.create_test_bucket(MULTIPART_COMPRESSION_BUCKET).await?;
+
+    let object_key = "multipart-compressible.txt";
+    let part1 = generate_compressible_data(MPU_PART1_SIZE);
+    let part2 = generate_compressible_data(MPU_PART2_SIZE);
+    let mut original_data = part1.clone();
+    original_data.extend_from_slice(&part2);
+    let total_size = original_data.len();
+
+    multipart_upload(&client, MULTIPART_COMPRESSION_BUCKET, object_key, &[&part1, &part2]).await?;
+
+    let head_response = client
+        .head_object()
+        .bucket(MULTIPART_COMPRESSION_BUCKET)
+        .key(object_key)
+        .send()
+        .await?;
+    assert_eq!(
+        head_response.content_length().unwrap_or(0) as usize,
+        total_size,
+        "Content-Length should be the logical object size"
+    );
+
+    let part_files = find_part_files(&env.temp_dir, MULTIPART_COMPRESSION_BUCKET, object_key);
+    assert!(!part_files.is_empty(), "expected on-disk part files for the multipart object");
+    let total_physical_size: u64 = part_files.iter().filter_map(|p| fs::metadata(p).ok()).map(|m| m.len()).sum();
+    assert!(
+        total_physical_size < (total_size / 2) as u64,
+        "Physical size {total_physical_size} should be well below original size {total_size} (multipart compression applied)"
+    );
+    info!("Multipart physical storage size: {total_physical_size} bytes (compressed from {total_size} bytes)");
+
+    // Full GET must reassemble both independently compressed parts.
+    let get_response = client
+        .get_object()
+        .bucket(MULTIPART_COMPRESSION_BUCKET)
+        .key(object_key)
+        .send()
+        .await?;
+    let downloaded = get_response.body.collect().await?.into_bytes();
+    assert_eq!(downloaded.len(), total_size);
+    assert_eq!(&downloaded[..], &original_data[..], "full GET data mismatch");
+
+    // Range fully inside part 1.
+    let range_inside_part1 = fetch_range(&client, MULTIPART_COMPRESSION_BUCKET, object_key, "bytes=1024-999423").await?;
+    assert_eq!(&range_inside_part1[..], &original_data[1024..999424], "part-1 range mismatch");
+
+    // Range crossing the part boundary.
+    let boundary_start = MPU_PART1_SIZE - 128 * 1024;
+    let boundary_end = MPU_PART1_SIZE + 128 * 1024 - 1;
+    let range_crossing = fetch_range(
+        &client,
+        MULTIPART_COMPRESSION_BUCKET,
+        object_key,
+        &format!("bytes={boundary_start}-{boundary_end}"),
+    )
+    .await?;
+    assert_eq!(
+        &range_crossing[..],
+        &original_data[boundary_start..boundary_end + 1],
+        "boundary-crossing range mismatch"
+    );
+
+    // Range fully inside part 2.
+    let part2_start = MPU_PART1_SIZE + 4096;
+    let part2_end = MPU_PART1_SIZE + 256 * 1024 - 1;
+    let range_inside_part2 = fetch_range(
+        &client,
+        MULTIPART_COMPRESSION_BUCKET,
+        object_key,
+        &format!("bytes={part2_start}-{part2_end}"),
+    )
+    .await?;
+    assert_eq!(
+        &range_inside_part2[..],
+        &original_data[part2_start..part2_end + 1],
+        "part-2 range mismatch"
+    );
+
+    // Suffix range (last 128 KiB, entirely in part 2).
+    let suffix_len = 128 * 1024;
+    let suffix = fetch_range(&client, MULTIPART_COMPRESSION_BUCKET, object_key, &format!("bytes=-{suffix_len}")).await?;
+    assert_eq!(&suffix[..], &original_data[total_size - suffix_len..], "suffix range mismatch");
+
+    // partNumber GETs must return each original part.
+    for (part_number, expected) in [(1, &part1), (2, &part2)] {
+        let response = client
+            .get_object()
+            .bucket(MULTIPART_COMPRESSION_BUCKET)
+            .key(object_key)
+            .part_number(part_number)
+            .send()
+            .await?;
+        let body = response.body.collect().await?.into_bytes();
+        assert_eq!(&body[..], &expected[..], "partNumber={part_number} GET mismatch");
+    }
+
+    info!("Multipart compression roundtrip test passed");
+    env.delete_test_bucket(MULTIPART_COMPRESSION_BUCKET).await?;
+    env.stop_server();
+    Ok(())
+}
+
+const MPU_HIGH_RATIO_BUCKET: &str = "compression-mpu-high-ratio-bucket";
+
+/// High-ratio binary multipart payload: the object key is on the compression allow-list, so the
+/// disk-compression path runs and each part is stored as many compressed blocks — the shape that
+/// reproduced the mid-payload Pending truncation (rustfs/rustfs#5957). Every GET shape must return
+/// the exact original bytes, and the stored size must show the data really was compressed.
+#[tokio::test]
+#[serial]
+async fn test_compression_multipart_high_ratio_binary_roundtrip() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    init_logging();
+    info!("Starting multipart high-ratio binary compression roundtrip test");
+
+    let mut env = RustFSTestEnvironment::new().await?;
+    start_rustfs_with_compression(&mut env).await?;
+
+    let client = env.create_s3_client();
+    env.create_test_bucket(MPU_HIGH_RATIO_BUCKET).await?;
+
+    let object_key = "multipart-high-ratio.txt";
+    let part1 = generate_high_ratio_binary_data(MPU_PART1_SIZE, 7);
+    let part2 = generate_high_ratio_binary_data(MPU_PART2_SIZE, 61);
+    let mut original_data = part1.clone();
+    original_data.extend_from_slice(&part2);
+    let total_size = original_data.len();
+
+    multipart_upload(&client, MPU_HIGH_RATIO_BUCKET, object_key, &[&part1, &part2]).await?;
+
+    let head_response = client
+        .head_object()
+        .bucket(MPU_HIGH_RATIO_BUCKET)
+        .key(object_key)
+        .send()
+        .await?;
+    assert_eq!(
+        head_response.content_length().unwrap_or(0) as usize,
+        total_size,
+        "Content-Length should be the logical object size"
+    );
+
+    // This pattern compresses to roughly 1/50 of its logical size, so a comfortably loose 2x
+    // margin still proves the parts were stored compressed rather than raw or double-encoded.
+    let part_files = find_part_files(&env.temp_dir, MPU_HIGH_RATIO_BUCKET, object_key);
+    assert!(!part_files.is_empty(), "expected on-disk part files for the multipart object");
+    let total_physical_size: u64 = part_files.iter().filter_map(|p| fs::metadata(p).ok()).map(|m| m.len()).sum();
+    assert!(
+        total_physical_size < (total_size as u64) / 2,
+        "Physical size {total_physical_size} should be far below the logical size {total_size} for high-ratio data"
+    );
+    info!("High-ratio multipart physical storage size: {total_physical_size} bytes (logical {total_size} bytes)");
+
+    info!("step: full GET");
+    let get_response = client
+        .get_object()
+        .bucket(MPU_HIGH_RATIO_BUCKET)
+        .key(object_key)
+        .send()
+        .await?;
+    let downloaded = get_response.body.collect().await?.into_bytes();
+    assert_eq!(downloaded.len(), total_size);
+    assert_eq!(&downloaded[..], &original_data[..], "full GET data mismatch");
+
+    // Range crossing the part boundary.
+    info!("step: boundary range GET");
+    let boundary_start = MPU_PART1_SIZE - 128 * 1024;
+    let boundary_end = MPU_PART1_SIZE + 128 * 1024 - 1;
+    let range_crossing = fetch_range(
+        &client,
+        MPU_HIGH_RATIO_BUCKET,
+        object_key,
+        &format!("bytes={boundary_start}-{boundary_end}"),
+    )
+    .await?;
+    assert_eq!(
+        &range_crossing[..],
+        &original_data[boundary_start..boundary_end + 1],
+        "boundary-crossing range mismatch"
+    );
+
+    // partNumber GET for the trailing part.
+    info!("step: partNumber GET");
+    let part2_response = client
+        .get_object()
+        .bucket(MPU_HIGH_RATIO_BUCKET)
+        .key(object_key)
+        .part_number(2)
+        .send()
+        .await?;
+    let part2_body = part2_response.body.collect().await?.into_bytes();
+    assert_eq!(&part2_body[..], &part2[..], "partNumber=2 GET mismatch");
+
+    info!("Multipart high-ratio binary compression roundtrip test passed");
+    env.delete_test_bucket(MPU_HIGH_RATIO_BUCKET).await?;
+    env.stop_server();
+    Ok(())
+}
+
+const MPU_COPY_COMPRESSION_BUCKET: &str = "compression-mpu-copy-bucket";
+const MPU_COPY_SOURCE_SIZE: usize = 6 * 1024 * 1024;
+const MPU_COPY_RANGE_LEN: usize = 5 * 1024 * 1024;
+
+/// UploadPartCopy feeds a part from an already stored (and already compressed) object. The copied
+/// range must be decompressed on read and re-compressed into the destination part, so the final
+/// object has to match "source prefix + uploaded tail" byte for byte.
+#[tokio::test]
+#[serial]
+async fn test_compression_multipart_upload_part_copy_roundtrip() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    init_logging();
+    info!("Starting multipart upload-part-copy compression roundtrip test");
+
+    let mut env = RustFSTestEnvironment::new().await?;
+    start_rustfs_with_compression(&mut env).await?;
+
+    let client = env.create_s3_client();
+    env.create_test_bucket(MPU_COPY_COMPRESSION_BUCKET).await?;
+
+    // Source object: a plain PUT that goes through the single-stream compression path.
+    let source_key = "copy-source.txt";
+    let source_data = generate_compressible_data(MPU_COPY_SOURCE_SIZE);
+    client
+        .put_object()
+        .bucket(MPU_COPY_COMPRESSION_BUCKET)
+        .key(source_key)
+        .body(ByteStream::from(source_data.clone()))
+        .send()
+        .await?;
+
+    // Destination object: part 1 copied from the source, part 2 uploaded directly.
+    let target_key = "copy-target.txt";
+    let part2 = generate_compressible_data(MPU_PART2_SIZE);
+    let mut expected_data = source_data[..MPU_COPY_RANGE_LEN].to_vec();
+    expected_data.extend_from_slice(&part2);
+    let total_size = expected_data.len();
+
+    let create = client
+        .create_multipart_upload()
+        .bucket(MPU_COPY_COMPRESSION_BUCKET)
+        .key(target_key)
+        .send()
+        .await?;
+    let upload_id = create.upload_id().ok_or("missing upload id")?.to_string();
+
+    let copy_part = client
+        .upload_part_copy()
+        .bucket(MPU_COPY_COMPRESSION_BUCKET)
+        .key(target_key)
+        .upload_id(&upload_id)
+        .part_number(1)
+        .copy_source(format!("{MPU_COPY_COMPRESSION_BUCKET}/{source_key}"))
+        .copy_source_range(format!("bytes=0-{}", MPU_COPY_RANGE_LEN - 1))
+        .send()
+        .await?;
+    let copy_etag = copy_part
+        .copy_part_result()
+        .and_then(|r| r.e_tag())
+        .ok_or("missing copy part etag")?
+        .to_string();
+
+    let uploaded_part = client
+        .upload_part()
+        .bucket(MPU_COPY_COMPRESSION_BUCKET)
+        .key(target_key)
+        .upload_id(&upload_id)
+        .part_number(2)
+        .body(ByteStream::from(part2.clone()))
+        .send()
+        .await?;
+
+    client
+        .complete_multipart_upload()
+        .bucket(MPU_COPY_COMPRESSION_BUCKET)
+        .key(target_key)
+        .upload_id(&upload_id)
+        .multipart_upload(
+            CompletedMultipartUpload::builder()
+                .parts(CompletedPart::builder().part_number(1).e_tag(copy_etag).build())
+                .parts(
+                    CompletedPart::builder()
+                        .part_number(2)
+                        .e_tag(uploaded_part.e_tag().unwrap_or_default())
+                        .build(),
+                )
+                .build(),
+        )
+        .send()
+        .await?;
+
+    let head_response = client
+        .head_object()
+        .bucket(MPU_COPY_COMPRESSION_BUCKET)
+        .key(target_key)
+        .send()
+        .await?;
+    assert_eq!(
+        head_response.content_length().unwrap_or(0) as usize,
+        total_size,
+        "Content-Length should be the logical object size"
+    );
+
+    let part_files = find_part_files(&env.temp_dir, MPU_COPY_COMPRESSION_BUCKET, target_key);
+    assert!(!part_files.is_empty(), "expected on-disk part files for the copied object");
+    let total_physical_size: u64 = part_files.iter().filter_map(|p| fs::metadata(p).ok()).map(|m| m.len()).sum();
+    assert!(
+        total_physical_size < (total_size / 2) as u64,
+        "Physical size {total_physical_size} should be well below original size {total_size} (copied part compression applied)"
+    );
+
+    let get_response = client
+        .get_object()
+        .bucket(MPU_COPY_COMPRESSION_BUCKET)
+        .key(target_key)
+        .send()
+        .await?;
+    let downloaded = get_response.body.collect().await?.into_bytes();
+    assert_eq!(downloaded.len(), total_size);
+    assert_eq!(&downloaded[..], &expected_data[..], "copied multipart GET data mismatch");
+
+    info!("Multipart upload-part-copy compression roundtrip test passed");
+    env.delete_test_bucket(MPU_COPY_COMPRESSION_BUCKET).await?;
+    env.stop_server();
+    Ok(())
+}
+
+const MPU_THREE_PARTS_BUCKET: &str = "compression-mpu-three-parts-bucket";
+const MPU_THREE_PARTS_TAIL_SIZE: usize = 512 * 1024;
+
+/// Three-part upload with uneven part sizes: each partNumber GET must map back to exactly one
+/// compressed part stream, and a suffix range must resolve inside the trailing part.
+#[tokio::test]
+#[serial]
+async fn test_compression_multipart_three_parts_part_number_gets() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    init_logging();
+    info!("Starting three-part multipart compression partNumber test");
+
+    let mut env = RustFSTestEnvironment::new().await?;
+    start_rustfs_with_compression(&mut env).await?;
+
+    let client = env.create_s3_client();
+    env.create_test_bucket(MPU_THREE_PARTS_BUCKET).await?;
+
+    let object_key = "multipart-three-parts.txt";
+    let part1 = generate_compressible_data(MPU_PART1_SIZE);
+    let part2 = generate_compressible_data(MPU_PART1_SIZE);
+    let part3 = generate_compressible_data(MPU_THREE_PARTS_TAIL_SIZE);
+    let mut original_data = part1.clone();
+    original_data.extend_from_slice(&part2);
+    original_data.extend_from_slice(&part3);
+    let total_size = original_data.len();
+
+    multipart_upload(&client, MPU_THREE_PARTS_BUCKET, object_key, &[&part1, &part2, &part3]).await?;
+
+    let head_response = client
+        .head_object()
+        .bucket(MPU_THREE_PARTS_BUCKET)
+        .key(object_key)
+        .send()
+        .await?;
+    assert_eq!(
+        head_response.content_length().unwrap_or(0) as usize,
+        total_size,
+        "Content-Length should be the logical object size"
+    );
+
+    let part_files = find_part_files(&env.temp_dir, MPU_THREE_PARTS_BUCKET, object_key);
+    assert!(!part_files.is_empty(), "expected on-disk part files for the multipart object");
+    let total_physical_size: u64 = part_files.iter().filter_map(|p| fs::metadata(p).ok()).map(|m| m.len()).sum();
+    assert!(
+        total_physical_size < (total_size / 2) as u64,
+        "Physical size {total_physical_size} should be well below original size {total_size} (multipart compression applied)"
+    );
+
+    // Every partNumber GET must return exactly the bytes of the corresponding uploaded part.
+    for (part_number, expected) in [(1, &part1), (2, &part2), (3, &part3)] {
+        let response = client
+            .get_object()
+            .bucket(MPU_THREE_PARTS_BUCKET)
+            .key(object_key)
+            .part_number(part_number)
+            .send()
+            .await?;
+        let body = response.body.collect().await?.into_bytes();
+        assert_eq!(&body[..], &expected[..], "partNumber={part_number} GET mismatch");
+    }
+
+    // Suffix range (last 64 KiB) resolves inside the trailing part.
+    let suffix_len = 64 * 1024;
+    let suffix = fetch_range(&client, MPU_THREE_PARTS_BUCKET, object_key, &format!("bytes=-{suffix_len}")).await?;
+    assert_eq!(&suffix[..], &original_data[total_size - suffix_len..], "suffix range mismatch");
+
+    info!("Three-part multipart compression partNumber test passed");
+    env.delete_test_bucket(MPU_THREE_PARTS_BUCKET).await?;
+    env.stop_server();
+    Ok(())
+}
+
+const MPU_SSE_COMPRESSION_BUCKET: &str = "compression-mpu-sse-bucket";
+
+async fn start_rustfs_with_compression_and_sse(
+    env: &mut RustFSTestEnvironment,
+) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    use base64::Engine;
+    env.cleanup_existing_processes().await?;
+
+    let binary_path = rustfs_binary_path();
+    let master_key = base64::engine::general_purpose::STANDARD.encode([0x42u8; 32]);
+    // Server output goes to a file inside the per-test temp dir so a failing
+    // run can be diagnosed from the child's logs.
+    let server_log = std::fs::File::create(format!("{}/server.log", env.temp_dir))?;
+    let server_log_err = server_log.try_clone()?;
+    let process = Command::new(&binary_path)
+        .env("RUSTFS_CONSOLE_ENABLE", "false")
+        .env("RUSTFS_COMPRESSION_ENABLED", "true")
+        .env("RUSTFS_COMPRESSION_MULTIPART_ENABLED", "true")
+        .env("RUSTFS_SSE_S3_MASTER_KEY", master_key)
+        .env("RUST_LOG", "rustfs=info,rustfs_ecstore=info")
+        .stdout(std::process::Stdio::from(server_log))
+        .stderr(std::process::Stdio::from(server_log_err))
+        .args([
+            "--address",
+            &env.address,
+            "--access-key",
+            &env.access_key,
+            "--secret-key",
+            &env.secret_key,
+            &env.temp_dir,
+        ])
+        .spawn()?;
+
+    env.process = Some(process);
+
+    info!("Waiting for RustFS server with compression + SSE-S3 enabled on {}", env.address);
+    for i in 0..30 {
+        if TcpStream::connect(&env.address).await.is_ok() {
+            info!("RustFS server is ready after {} attempts", i + 1);
+            return Ok(());
+        }
+        if i == 29 {
+            return Err("RustFS server failed to become ready".into());
+        }
+        sleep(Duration::from_secs(1)).await;
+    }
+    Ok(())
+}
+
+/// SSE-S3 + disk compression multipart: each part is compressed and then encrypted, and every GET
+/// shape must still return the original plaintext bytes. Physical size must shrink because the
+/// compression runs before encryption.
+#[tokio::test]
+#[serial]
+async fn test_compression_multipart_sse_s3_roundtrip() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    use aws_sdk_s3::types::ServerSideEncryption;
+
+    init_logging();
+    info!("Starting SSE-S3 multipart compression roundtrip test");
+
+    let mut env = RustFSTestEnvironment::new().await?;
+    start_rustfs_with_compression_and_sse(&mut env).await?;
+
+    let client = env.create_s3_client();
+    env.create_test_bucket(MPU_SSE_COMPRESSION_BUCKET).await?;
+
+    let object_key = "multipart-sse-compressible.txt";
+    let part1 = generate_compressible_data(MPU_PART1_SIZE);
+    let part2 = generate_compressible_data(MPU_PART2_SIZE);
+    let mut original_data = part1.clone();
+    original_data.extend_from_slice(&part2);
+    let total_size = original_data.len();
+
+    let create = client
+        .create_multipart_upload()
+        .bucket(MPU_SSE_COMPRESSION_BUCKET)
+        .key(object_key)
+        .server_side_encryption(ServerSideEncryption::Aes256)
+        .send()
+        .await?;
+    let upload_id = create.upload_id().ok_or("missing upload id")?.to_string();
+
+    let mut completed_parts = Vec::new();
+    for (i, part) in [&part1, &part2].into_iter().enumerate() {
+        let part_number = (i + 1) as i32;
+        let upload = client
+            .upload_part()
+            .bucket(MPU_SSE_COMPRESSION_BUCKET)
+            .key(object_key)
+            .upload_id(&upload_id)
+            .part_number(part_number)
+            .body(ByteStream::from(part.clone()))
+            .send()
+            .await?;
+        completed_parts.push(
+            CompletedPart::builder()
+                .part_number(part_number)
+                .e_tag(upload.e_tag().unwrap_or_default())
+                .build(),
+        );
+    }
+
+    client
+        .complete_multipart_upload()
+        .bucket(MPU_SSE_COMPRESSION_BUCKET)
+        .key(object_key)
+        .upload_id(&upload_id)
+        .multipart_upload(CompletedMultipartUpload::builder().set_parts(Some(completed_parts)).build())
+        .send()
+        .await?;
+
+    let head_response = client
+        .head_object()
+        .bucket(MPU_SSE_COMPRESSION_BUCKET)
+        .key(object_key)
+        .send()
+        .await?;
+    assert_eq!(
+        head_response.content_length().unwrap_or(0) as usize,
+        total_size,
+        "Content-Length should be the logical object size"
+    );
+    assert_eq!(
+        head_response.server_side_encryption(),
+        Some(&ServerSideEncryption::Aes256),
+        "HEAD must report SSE-S3"
+    );
+
+    let part_files = find_part_files(&env.temp_dir, MPU_SSE_COMPRESSION_BUCKET, object_key);
+    assert!(!part_files.is_empty(), "expected on-disk part files for the multipart object");
+    let total_physical_size: u64 = part_files.iter().filter_map(|p| fs::metadata(p).ok()).map(|m| m.len()).sum();
+    assert!(
+        total_physical_size < (total_size / 2) as u64,
+        "Physical size {total_physical_size} should be well below original size {total_size} (compress-then-encrypt applied)"
+    );
+
+    let get_response = client
+        .get_object()
+        .bucket(MPU_SSE_COMPRESSION_BUCKET)
+        .key(object_key)
+        .send()
+        .await?;
+    let downloaded = get_response.body.collect().await?.into_bytes();
+    assert_eq!(downloaded.len(), total_size);
+    assert_eq!(&downloaded[..], &original_data[..], "SSE-S3 multipart full GET data mismatch");
+
+    // Range crossing the part boundary must decrypt and decompress across parts.
+    let boundary_start = MPU_PART1_SIZE - 64 * 1024;
+    let boundary_end = MPU_PART1_SIZE + 64 * 1024 - 1;
+    let range_crossing = fetch_range(
+        &client,
+        MPU_SSE_COMPRESSION_BUCKET,
+        object_key,
+        &format!("bytes={boundary_start}-{boundary_end}"),
+    )
+    .await?;
+    assert_eq!(
+        &range_crossing[..],
+        &original_data[boundary_start..boundary_end + 1],
+        "SSE-S3 boundary-crossing range mismatch"
+    );
+
+    // partNumber GET for the trailing part.
+    let part2_response = client
+        .get_object()
+        .bucket(MPU_SSE_COMPRESSION_BUCKET)
+        .key(object_key)
+        .part_number(2)
+        .send()
+        .await?;
+    let part2_body = part2_response.body.collect().await?.into_bytes();
+    assert_eq!(&part2_body[..], &part2[..], "SSE-S3 partNumber=2 GET mismatch");
+
+    info!("SSE-S3 multipart compression roundtrip test passed");
+    env.delete_test_bucket(MPU_SSE_COMPRESSION_BUCKET).await?;
+    env.stop_server();
+    Ok(())
+}
@@ -76,6 +76,18 @@ const SOURCE_MTIME_HEADERS: [&str; 2] = ["x-rustfs-source-mtime", "x-minio-sourc
 const SOURCE_REPLICATION_REQUEST_HEADERS: [&str; 2] =
    ["x-rustfs-source-replication-request", "x-minio-source-replication-request"];
 const SOURCE_ETAG_HEADERS: [&str; 2] = ["x-rustfs-source-etag", "x-minio-source-etag"];
+const SOURCE_TAGGING_TIMESTAMP_HEADERS: [&str; 2] = [
+    "x-rustfs-source-replication-tagging-timestamp",
+    "x-minio-source-replication-tagging-timestamp",
+];
+const SOURCE_RETENTION_TIMESTAMP_HEADERS: [&str; 2] = [
+    "x-rustfs-source-replication-retention-timestamp",
+    "x-minio-source-replication-retention-timestamp",
+];
+const SOURCE_LEGALHOLD_TIMESTAMP_HEADERS: [&str; 2] = [
+    "x-rustfs-source-replication-legalhold-timestamp",
+    "x-minio-source-replication-legalhold-timestamp",
+];
 const RESERVED_BUCKET_PREFIXES: [&str; 3] = ["xn--", "sthree-", "amzn-s3-demo-"];
 const RESERVED_BUCKET_SUFFIXES: [&str; 6] = ["-s3alias", "--ol-s3", ".mrap", "--x-s3", "--table-s3", "-an"];

@@ -118,6 +130,25 @@ pub enum FaultAction {
    WrongEtag,
 }

+/// Replication LWW timestamp headers observed on a request, journaled so
+/// sender-side tests can assert what a real target would receive.
+#[derive(Debug, Clone, Default, PartialEq, Eq)]
+pub struct ReplicationTimestampHeaders {
+    pub tagging: Option<String>,
+    pub retention: Option<String>,
+    pub legalhold: Option<String>,
+}
+
+impl ReplicationTimestampHeaders {
+    fn from_headers(headers: &HeaderMap) -> Self {
+        Self {
+            tagging: header_value(headers, &SOURCE_TAGGING_TIMESTAMP_HEADERS).map(bounded_journal_value),
+            retention: header_value(headers, &SOURCE_RETENTION_TIMESTAMP_HEADERS).map(bounded_journal_value),
+            legalhold: header_value(headers, &SOURCE_LEGALHOLD_TIMESTAMP_HEADERS).map(bounded_journal_value),
+        }
+    }
+}
+
 /// Credential-free request metadata retained for deterministic assertions.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct RequestRecord {
@@ -131,6 +162,7 @@ pub struct RequestRecord {
    pub part_number: Option<i32>,
    pub content_length: Option<u64>,
    pub consumed_bytes: Option<usize>,
+    pub replication_timestamps: ReplicationTimestampHeaders,
    pub fault: Option<FaultAction>,
 }

@@ -536,7 +568,15 @@ impl S3Access for FaultAccess {
            .get(CONTENT_LENGTH)
            .and_then(|value| value.to_str().ok())
            .and_then(|value| value.parse().ok());
-        let fault = record_request(&self.control, operation, context.method().clone(), parsed, content_length);
+        let replication_timestamps = ReplicationTimestampHeaders::from_headers(context.headers());
+        let fault = record_request(
+            &self.control,
+            operation,
+            context.method().clone(),
+            parsed,
+            content_length,
+            replication_timestamps,
+        );
        if let Some(RequestFault {
            action: FaultAction::Status(status),
            ..
@@ -589,6 +629,7 @@ fn record_request(
    method: Method,
    parsed: ParsedRequest,
    content_length: Option<u64>,
+    replication_timestamps: ReplicationTimestampHeaders,
 ) -> Option<RequestFault> {
    let mut state = lock(control);
    let action = parsed
@@ -613,6 +654,7 @@ fn record_request(
        part_number: parsed.part_number,
        content_length,
        consumed_bytes: None,
+        replication_timestamps,
        fault: action.clone(),
    });
    action.map(|action| RequestFault { sequence, action })
@@ -1699,6 +1741,52 @@ mod tests {
            .await?)
    }

+    #[tokio::test]
+    async fn journals_replication_timestamp_headers() -> Result<(), BoxError> {
+        let target = FakeS3Target::start().await?;
+        target.create_bucket("target-bucket");
+        let client = client(&target);
+
+        client
+            .put_object()
+            .bucket("target-bucket")
+            .key("plain")
+            .body(ByteStream::from_static(b"plain"))
+            .send()
+            .await?;
+        client
+            .put_object()
+            .bucket("target-bucket")
+            .key("stamped")
+            .body(ByteStream::from_static(b"stamped"))
+            .customize()
+            .map_request(move |mut request| {
+                let headers = request.headers_mut();
+                headers.insert("x-rustfs-source-replication-tagging-timestamp", "2026-01-02T03:04:05Z");
+                headers.insert("x-minio-source-replication-retention-timestamp", "2026-01-02T03:04:06Z");
+                headers.insert("x-rustfs-source-replication-legalhold-timestamp", "2026-01-02T03:04:07Z");
+                Ok::<_, std::convert::Infallible>(request)
+            })
+            .send()
+            .await?;
+
+        let requests = target.requests();
+        let plain = requests
+            .iter()
+            .find(|record| record.operation == Operation::PutObject && record.key.as_deref() == Some("plain"))
+            .expect("plain PUT must be journaled");
+        assert_eq!(plain.replication_timestamps, ReplicationTimestampHeaders::default());
+
+        let stamped = requests
+            .iter()
+            .find(|record| record.operation == Operation::PutObject && record.key.as_deref() == Some("stamped"))
+            .expect("stamped PUT must be journaled");
+        assert_eq!(stamped.replication_timestamps.tagging.as_deref(), Some("2026-01-02T03:04:05Z"));
+        assert_eq!(stamped.replication_timestamps.retention.as_deref(), Some("2026-01-02T03:04:06Z"));
+        assert_eq!(stamped.replication_timestamps.legalhold.as_deref(), Some("2026-01-02T03:04:07Z"));
+        Ok(())
+    }
+
    macro_rules! assert_sdk_error {
        ($error:expr, $status:expr, $code:expr) => {{
            let error = &$error;
@@ -2985,6 +3073,7 @@ mod tests {
                        part_number: None,
                    },
                    Some(0),
+                    ReplicationTimestampHeaders::default(),
                );
            }
            let records = lock(&control).requests.clone();
@@ -3006,6 +3095,7 @@ mod tests {
                    part_number: None,
                },
                None,
+                ReplicationTimestampHeaders::default(),
            );
            {
                let bounded_records = lock(&bounded_control);
@@ -1828,33 +1828,36 @@ async fn four_node_compressed_inline_fallback() -> TestResult {
    Ok(())
 }

+/// Multipart disk compression is live again, so a compression-enabled cluster classifies multipart objects as compressed and the roundtrip (full GET plus partNumber GET) must still return the original bytes.
+/// Reverting the multipart compression fix must fail this test.
 #[tokio::test]
 #[serial]
-async fn four_node_multipart_ignores_disk_compression_fallback() -> TestResult {
+async fn four_node_multipart_disk_compression_roundtrip() -> TestResult {
    init_logging();

    let collector = OtlpMetricCollector::start().await?;
    let mut cluster = RustFSTestClusterEnvironment::new(4).await?;
    configure_reader_metric_cluster(&mut cluster, &collector);
    cluster.set_env("RUSTFS_COMPRESSION_ENABLED", "true");
+    cluster.set_env("RUSTFS_COMPRESSION_MULTIPART_ENABLED", "true");
    cluster.start().await?;

-    let bucket = "inline-multipart-compression-fallback";
+    let bucket = "inline-multipart-compression-roundtrip";
    cluster.create_test_bucket(bucket).await?;
    let client = cluster.create_s3_client(0)?;
-    let key = "multipart/compression-disabled.txt";
+    let key = "multipart/compressed.txt";
    let (body, second_part, etag) = put_two_part_multipart(&client, bucket, key).await?;

    assert_reader_path(
        &collector,
        &client,
-        ReaderPathExpectation::for_class(ReaderObject::new(bucket, key, &body, etag.as_deref(), None), LEGACY_DUPLEX, MULTIPART),
+        ReaderPathExpectation::for_class(ReaderObject::new(bucket, key, &body, etag.as_deref(), None), LEGACY_DUPLEX, COMPRESSED),
    )
    .await?;
    assert_part_number_reader_path(
        &collector,
        &client,
-        PartNumberReaderPathExpectation::new(bucket, key, &second_part, body.len(), MULTIPART, LEGACY_DUPLEX),
+        PartNumberReaderPathExpectation::new(bucket, key, &second_part, body.len(), COMPRESSED, LEGACY_DUPLEX),
    )
    .await?;

@@ -1871,6 +1874,7 @@ async fn four_node_mixed_msgpack_compat_mode_preserves_fallback_controls() -> Te
    let sse_master_key = base64::engine::general_purpose::STANDARD.encode([0x42u8; 32]);
    cluster.set_env("RUSTFS_SSE_S3_MASTER_KEY", sse_master_key);
    cluster.set_env("RUSTFS_COMPRESSION_ENABLED", "true");
+    cluster.set_env("RUSTFS_COMPRESSION_MULTIPART_ENABLED", "true");
    configure_mixed_msgpack_cluster(&mut cluster, &collector)?;
    cluster.start().await?;

@@ -1890,14 +1894,21 @@ async fn four_node_mixed_msgpack_compat_mode_preserves_fallback_controls() -> Te
        ReaderPathExpectation::for_class(
            ReaderObject::new(bucket, multipart_key, &multipart_body, multipart_etag.as_deref(), None),
            LEGACY_DUPLEX,
-            MULTIPART,
+            COMPRESSED,
        ),
    )
    .await?;
    assert_part_number_reader_path(
        &collector,
        &client,
-        PartNumberReaderPathExpectation::new(bucket, multipart_key, &second_part, multipart_body.len(), MULTIPART, LEGACY_DUPLEX),
+        PartNumberReaderPathExpectation::new(
+            bucket,
+            multipart_key,
+            &second_part,
+            multipart_body.len(),
+            COMPRESSED,
+            LEGACY_DUPLEX,
+        ),
    )
    .await?;
    assert_msgpack_decode_observed(&collector, &decode_before).await?;
@@ -2353,7 +2364,11 @@ async fn four_node_mixed_msgpack_compat_mode_preserves_fallback_controls_during_
    hot_client.create_bucket().bucket(bucket).send().await?;
    put_lifecycle_with_transition_retry(&hot_client, bucket, &tier_name).await?;

-    let key = "transition/mixed-multipart.bin";
+    // `.zip` sits on the disk-compression exclusion list: this test pins
+    // msgpack compat controls across ILM transition, and a compressed object
+    // would classify as `compressed` instead of `remote` (and the warm-tier
+    // read path does not decode compression — tracked separately).
+    let key = "transition/mixed-multipart.zip";
    let (body, second_part, etag) = put_two_part_multipart(&hot_client, bucket, key).await?;
    wait_for_transition(&hot_client, bucket, key, &tier_name).await?;
    assert!(
@@ -97,7 +97,7 @@ async fn start_enforcing_ilm_server(env: &mut LocalKMSTestEnvironment) -> TestRe

    let envs = [
        ("RUSTFS_KMS_ALLOW_INSECURE_DEV_DEFAULTS", "true"),
-        ("RUSTFS_KMS_ENFORCE_SSE_KEY_POLICY", "false"),
+        ("RUSTFS_KMS_ENFORCE_SSE_KEY_POLICY", "true"),
        ("RUSTFS_SCANNER_CYCLE", "1"),
        ("RUSTFS_ILM_PROCESS_TIME", "1"),
        ("RUSTFS_ILM_DEBUG_DAY_SECS", "2"),
@@ -486,7 +486,6 @@ async fn ilm_expiration_on_sse_kms_bucket_under_enforcement() -> TestResult {
 /// depend on scanner scheduling; the 1s scanner cycle stays on as a backstop.
 #[tokio::test]
 #[serial]
-#[ignore = "pins rustfs/rustfs#6025: GET on a transitioned managed-SSE object silently returns corrupt bytes (fails with enforcement on AND off, so it is not an authorization regression); un-ignore with the fix"]
 async fn ilm_transition_on_sse_kms_bucket_under_enforcement_reads_back() -> TestResult {
    init_logging();

@@ -131,16 +131,19 @@ pub mod bucket {
    }

    pub mod metadata_sys {
+        #[cfg(feature = "test-util")]
+        pub use crate::bucket::metadata_sys::ConfigWriteLockProbe;
        pub use crate::bucket::metadata_sys::{
            BucketMetadataMutationGuard, BucketMetadataSys, ObjectLockConfigState, acquire_bucket_metadata_transaction_lock,
-            capture_bucket_metadata_incarnation, delete, delete_if_incarnation, get, get_accelerate_config, get_bucket_policy,
+            acquire_bucket_metadata_transaction_lock_for_incarnation, capture_bucket_metadata_incarnation, delete,
+            delete_if_incarnation, delete_under_transaction_lock, get, get_accelerate_config, get_bucket_policy,
            get_bucket_policy_raw, get_bucket_targets_config, get_config_from_disk, get_cors_config, get_durability_config,
            get_global_bucket_metadata_sys, get_lifecycle_config, get_logging_config, get_notification_config,
            get_object_lock_config, get_object_lock_config_state, get_public_access_block_config, get_quota_config,
            get_replication_config, get_request_payment_config, get_sse_config, get_tagging_config, get_versioning_config,
            get_website_config, init_bucket_metadata_sys, list_bucket_targets, reload_bucket_metadata, remove_bucket_metadata,
            set_bucket_metadata, update, update_bucket_targets_under_transaction_lock, update_config_with, update_if_incarnation,
-            update_under_transaction_lock,
+            update_quota_if_incarnation, update_under_transaction_lock,
        };
    }

@@ -182,17 +185,18 @@ pub mod bucket {
            mrf_backlog_observability_snapshot,
        };
        pub use crate::bucket::replication::{
-            BucketReplicationResyncStatus, BucketReplicationStats, BucketStats, DeleteReplicationConfigSnapshot,
-            DeletedObjectReplicationInfo, DurableMrfBacklog, DynReplicationPool, MrfOpKind, MrfReplicateEntry,
-            MustReplicateOptions, ObjectOpts, REMOTE_TARGET_CAPABILITY_CONTRACT_VERSION, REMOTE_TARGET_UNSUPPORTED_FIELDS,
-            REMOTE_TARGET_WRITABLE_FIELDS, REPLICATE_INCOMING_DELETE, REPLICATION_CAPABILITY_CONTRACT_VERSION,
-            REPLICATION_READ_ONLY_HISTORICAL_FIELDS, REPLICATION_WRITABLE_FIELDS, ReplicateDecision, ReplicateObjectInfo,
-            ReplicationBatchAdmission, ReplicationConfig, ReplicationConfigStructureError, ReplicationConfigurationExt,
-            ReplicationDeleteScheduleInput, ReplicationDeleteStateSource, ReplicationHealQueueResult, ReplicationObjectBridge,
-            ReplicationObjectIO, ReplicationOperation, ReplicationPoolTrait, ReplicationPriority, ReplicationQueueAdmission,
-            ReplicationScannerBridge, ReplicationState, ReplicationStats, ReplicationStatusType, ReplicationStorage,
-            ReplicationTargetValidationError, ReplicationType, ResyncOpts, ResyncStatusType, RuntimeReplicationTargetBacklog,
-            TargetReplicationResyncStatus, VersionPurgeStatusType, commit_force_delete_intent, complete_force_delete_intent,
+            BucketReplicationResyncStatus, BucketReplicationStat, BucketReplicationStats, BucketStats,
+            DeleteReplicationConfigSnapshot, DeletedObjectReplicationInfo, DurableMrfBacklog, DynReplicationPool, InQueueMetric,
+            MrfOpKind, MrfReplicateEntry, MustReplicateOptions, ObjectOpts, REMOTE_TARGET_CAPABILITY_CONTRACT_VERSION,
+            REMOTE_TARGET_UNSUPPORTED_FIELDS, REMOTE_TARGET_WRITABLE_FIELDS, REPLICATE_INCOMING_DELETE,
+            REPLICATION_CAPABILITY_CONTRACT_VERSION, REPLICATION_READ_ONLY_HISTORICAL_FIELDS, REPLICATION_WRITABLE_FIELDS,
+            ReplicateDecision, ReplicateObjectInfo, ReplicationBatchAdmission, ReplicationConfig,
+            ReplicationConfigStructureError, ReplicationConfigurationExt, ReplicationDeleteScheduleInput,
+            ReplicationDeleteStateSource, ReplicationHealQueueResult, ReplicationObjectBridge, ReplicationObjectIO,
+            ReplicationOperation, ReplicationPoolTrait, ReplicationPriority, ReplicationQueueAdmission, ReplicationScannerBridge,
+            ReplicationState, ReplicationStats, ReplicationStatusType, ReplicationStorage, ReplicationTargetValidationError,
+            ReplicationType, ResyncOpts, ResyncStatusType, RuntimeReplicationTargetBacklog, TargetReplicationResyncStatus,
+            VersionPurgeStatusType, XferStats, commit_force_delete_intent, complete_force_delete_intent,
            delete_replication_state_from_config, delete_replication_version_id, get_global_replication_pool,
            get_global_replication_stats, init_background_replication, invalid_replication_config_status_field,
            persist_force_delete_intent, read_durable_mrf_backlog, replication_state_to_filemeta, replication_status_to_filemeta,
@@ -276,7 +280,9 @@ pub mod cluster {
 }

 pub mod compression {
-    pub use crate::io_support::compress::{MIN_DISK_COMPRESSIBLE_SIZE, is_disk_compressible, is_disk_compression_enabled};
+    pub use crate::io_support::compress::{
+        MIN_DISK_COMPRESSIBLE_SIZE, is_disk_compressible, is_disk_compression_enabled, is_multipart_disk_compression_enabled,
+    };
 }

 pub mod config {
@@ -316,7 +322,7 @@ pub mod data_usage {
        DATA_USAGE_CACHE_NAME, apply_bucket_usage_memory_overlay, compute_bucket_usage,
        init_compression_total_memory_from_backend, invalidate_admin_data_usage_snapshot_cache,
        invalidate_data_usage_snapshot_cache, live_bucket_usage_computations, load_admin_data_usage_from_backend_cached,
-        load_compression_total_from_memory, load_data_usage_from_backend, load_data_usage_from_backend_cached,
+        load_compression_total_from_memory, load_data_usage_from_backend, load_data_usage_from_backend_cached, quota_object_size,
        record_bucket_delete_marker_memory, record_bucket_object_delete_memory, record_bucket_object_version_write_memory,
        record_bucket_object_write_memory, record_bucket_object_write_unknown_previous_memory, record_compression_total_memory,
        refresh_bucket_usage_from_object_layer, refresh_versioned_bucket_usage_from_object_layer,
@@ -403,8 +409,11 @@ pub mod metrics {
 }

 pub mod notification {
+    #[cfg(any(test, feature = "test-util"))]
+    pub use crate::services::notification_sys::rotate_cross_pool_fence_fleet_proof_for_test;
    pub use crate::services::notification_sys::{
-        NotificationPeerErr, NotificationSys, get_global_notification_sys, new_global_notification_sys,
+        CrossPoolFenceFleetProofToken, NotificationPeerErr, NotificationSys, acquire_cross_pool_fence_fleet_proof,
+        cross_pool_fence_fleet_proof_matches, get_global_notification_sys, new_global_notification_sys,
        start_remote_version_state_fleet_probe,
    };
 }
@@ -464,7 +473,8 @@ pub mod set_disk {

    #[cfg(feature = "test-util")]
    pub mod test_util {
-        pub use crate::set_disk::{PutObjectCommitBarrier, PutObjectCommitPause};
+        pub use crate::bucket::quota::reservation::fail_next_quota_ledger_save_for_test;
+        pub use crate::set_disk::{MultipartCommitBarrier, MultipartCommitPause, PutObjectCommitBarrier, PutObjectCommitPause};
    }
 }

@@ -58,7 +58,9 @@ use rustfs_utils::http::{
 };
 use rustfs_utils::http::{
    SUFFIX_FORCE_DELETE, SUFFIX_SOURCE_DELETEMARKER, SUFFIX_SOURCE_ETAG, SUFFIX_SOURCE_MTIME, SUFFIX_SOURCE_REPLICATION_CHECK,
-    SUFFIX_SOURCE_REPLICATION_REQUEST, SUFFIX_SOURCE_VERSION_ID, insert_header,
+    SUFFIX_SOURCE_REPLICATION_LEGALHOLD_TIMESTAMP, SUFFIX_SOURCE_REPLICATION_REQUEST,
+    SUFFIX_SOURCE_REPLICATION_RETENTION_TIMESTAMP, SUFFIX_SOURCE_REPLICATION_TAGGING_TIMESTAMP, SUFFIX_SOURCE_VERSION_ID,
+    insert_header,
 };
 use rustls_pki_types::pem::PemObject;
 use serde::{Deserialize, Serialize};
@@ -80,7 +82,6 @@ use tracing::warn;
 use url::Url;
 use uuid::Uuid;

-const DEFAULT_HEALTH_CHECK_RELOAD_DURATION: Duration = Duration::from_secs(30 * 60);
 const MAX_CONCURRENT_TARGET_HEALTH_CHECKS: usize = 16;
 const REDACTED_CREDENTIAL: &str = "<redacted>";

@@ -1476,9 +1477,12 @@ impl Default for AdvancedPutOptions {
            replication_status: ReplicationStatusType::Pending,
            source_mtime: OffsetDateTime::now_utc(),
            replication_request: false,
-            retention_timestamp: OffsetDateTime::now_utc(),
-            tagging_timestamp: OffsetDateTime::now_utc(),
-            legalhold_timestamp: OffsetDateTime::now_utc(),
+            // UNIX_EPOCH means "never modified": header() must not emit a
+            // timestamp header for it, otherwise a receiver would treat an
+            // unset category as a modification made right now.
+            retention_timestamp: OffsetDateTime::UNIX_EPOCH,
+            tagging_timestamp: OffsetDateTime::UNIX_EPOCH,
+            legalhold_timestamp: OffsetDateTime::UNIX_EPOCH,
            replication_validity_check: false,
        }
    }
@@ -1675,6 +1679,16 @@ impl PutObjectOptions {
            );
        }

+        for (suffix, timestamp) in [
+            (SUFFIX_SOURCE_REPLICATION_TAGGING_TIMESTAMP, self.internal.tagging_timestamp),
+            (SUFFIX_SOURCE_REPLICATION_RETENTION_TIMESTAMP, self.internal.retention_timestamp),
+            (SUFFIX_SOURCE_REPLICATION_LEGALHOLD_TIMESTAMP, self.internal.legalhold_timestamp),
+        ] {
+            if timestamp.unix_timestamp() != 0 {
+                insert_header(&mut header, suffix, timestamp.format(&Rfc3339).unwrap_or_default());
+            }
+        }
+
        if self.internal.replication_request {
            insert_header(&mut header, SUFFIX_SOURCE_REPLICATION_REQUEST, "true");
        }
@@ -2842,6 +2856,57 @@ mod tests {
        );
    }

+    #[test]
+    fn put_object_headers_carry_replication_timestamp_headers() {
+        // MinIO receivers resolve concurrent tag/retention/legal-hold edits by
+        // last-writer-wins on these headers (object-api-options.go parses them
+        // as RFC3339); a replica without them loses every conflict resolution.
+        let mut opts = PutObjectOptions::default();
+        opts.internal.replication_request = true;
+        let tagging = OffsetDateTime::from_unix_timestamp(1_700_000_001).expect("valid timestamp");
+        let retention = OffsetDateTime::from_unix_timestamp(1_700_000_002).expect("valid timestamp");
+        let legalhold = OffsetDateTime::from_unix_timestamp(1_700_000_003).expect("valid timestamp");
+        opts.internal.tagging_timestamp = tagging;
+        opts.internal.retention_timestamp = retention;
+        opts.internal.legalhold_timestamp = legalhold;
+
+        let header = opts.header();
+        for (suffix, expected) in [
+            ("source-replication-tagging-timestamp", tagging),
+            ("source-replication-retention-timestamp", retention),
+            ("source-replication-legalhold-timestamp", legalhold),
+        ] {
+            assert_eq!(
+                rustfs_utils::http::get_header(&header, suffix).as_deref(),
+                Some(expected.format(&Rfc3339).expect("RFC3339 timestamp").as_str()),
+                "replication put requests must carry the {suffix} header"
+            );
+        }
+    }
+
+    #[test]
+    fn put_object_headers_omit_unset_replication_timestamps() {
+        // UNIX_EPOCH means "never modified on the source"; sending it would
+        // make the receiver treat an unset category as a fresh modification.
+        let mut opts = PutObjectOptions::default();
+        opts.internal.replication_request = true;
+        opts.internal.tagging_timestamp = OffsetDateTime::UNIX_EPOCH;
+        opts.internal.retention_timestamp = OffsetDateTime::UNIX_EPOCH;
+        opts.internal.legalhold_timestamp = OffsetDateTime::UNIX_EPOCH;
+
+        let header = opts.header();
+        for suffix in [
+            "source-replication-tagging-timestamp",
+            "source-replication-retention-timestamp",
+            "source-replication-legalhold-timestamp",
+        ] {
+            assert!(
+                rustfs_utils::http::get_header(&header, suffix).is_none(),
+                "unset {suffix} must not be sent to replication targets"
+            );
+        }
+    }
+
    #[tokio::test]
    async fn get_remote_target_client_internal_rejects_loopback_endpoint() {
        let sys = BucketTargetSys::default();
@@ -46,15 +46,13 @@ use crate::bucket::lifecycle::transition_transaction::run_transition_transaction
 use crate::bucket::object_lock::ObjectLockApi;
 use crate::bucket::versioning::VersioningApi as _;
 use crate::bucket::versioning_sys::BucketVersioningSys;
-use crate::client::object_api_utils::new_getobjectreader;
 use crate::disk::error::DiskError;
 use crate::disk::{DeleteOptions, Disk, DiskAPI, RUSTFS_META_BUCKET, RUSTFS_META_MULTIPART_BUCKET, STORAGE_FORMAT_FILE};
 use crate::error::Error;
 use crate::error::StorageError;
-use crate::error::{
-    error_resp_to_object_err, is_err_object_not_found, is_err_read_quorum, is_err_version_not_found, is_network_or_host_down,
-};
+use crate::error::{is_err_object_not_found, is_err_read_quorum, is_err_version_not_found, is_network_or_host_down};
 use crate::object_api::{GetObjectReader, ObjectInfo, ObjectOptions};
+use crate::object_api::{ObjectEncryptionResolver, ReadPlan};
 use crate::services::tier::{
    tier::{TierConfigMgr, TierOperationLease, tier_destination_id_from_metadata},
    warm_backend::WarmBackendGetOpts,
@@ -128,11 +126,23 @@ const EVENT_LIFECYCLE_EXPIRED_DETECTED: &str = "lifecycle_expired_detected";
 const EVENT_LIFECYCLE_NOT_ENQUEUED: &str = "lifecycle_not_enqueued";
 const EVENT_LIFECYCLE_DELETE_DISPATCHED: &str = "lifecycle_delete_dispatched";
 const EVENT_LIFECYCLE_DELETE_COMPLETED: &str = "lifecycle_delete_completed";
+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 const EVENT_LIFECYCLE_TIER_AUDIT: &str = "lifecycle_tier_audit";
 const EVENT_LIFECYCLE_TIER_OPERATION_FAILED: &str = "lifecycle_tier_operation_failed";
 const EVENT_LIFECYCLE_DELETE_FAILED: &str = "lifecycle_delete_failed";

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub type TimeFn = Arc<dyn Fn() -> Pin<Box<dyn Future<Output = ()> + Send>> + Send + Sync + 'static>;
+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub type TraceFn =
    Arc<dyn Fn(String, HashMap<String, String>) -> Pin<Box<dyn Future<Output = ()> + Send>> + Send + Sync + 'static>;
 pub type ExpiryOpType = Box<dyn ExpiryOp + Send + Sync + 'static>;
@@ -142,9 +152,21 @@ static TIER_FREE_VERSION_RECOVERY_STARTED: OnceLock<()> = OnceLock::new();
 static MANUAL_TRANSITION_JOB_RECOVERY_STARTED: OnceLock<()> = OnceLock::new();

 pub const AMZ_OBJECT_TAGGING: &str = "X-Amz-Tagging";
+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub const AMZ_TAG_COUNT: &str = "x-amz-tagging-count";
+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub const AMZ_TAG_DIRECTIVE: &str = "X-Amz-Tagging-Directive";
 pub const AMZ_ENCRYPTION_AES: &str = "AES256";
+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub const AMZ_ENCRYPTION_KMS: &str = "aws:kms";

 pub const ERR_INVALID_STORAGECLASS: &str = "invalid tier.";
@@ -282,6 +304,10 @@ impl LifecycleSys {
        }
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+    )]
    pub fn trace(oi: &ObjectInfo) -> TraceFn {
        let bucket = oi.bucket.clone();
        let name = oi.name.clone();
@@ -572,6 +598,10 @@ async fn delete_free_version_remote_object(
    Ok(())
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 async fn delete_free_version_remote_object_then<T, F, Fut>(
    oi: &ObjectInfo,
    tier_config_mgr: &Arc<RwLock<TierConfigMgr>>,
@@ -2870,6 +2900,10 @@ fn stale_upload_default_due(initiated: OffsetDateTime, default_expiry: StdDurati
    initiated + time::Duration::seconds(default_expiry.as_secs() as i64)
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 async fn stale_upload_current_size(set: &Arc<SetDisks>, metadata: &HashMap<String, String>, upload_dir: &str) -> Option<usize> {
    stale_upload_current_size_with_opts(set, metadata, upload_dir, false).await
 }
@@ -3354,6 +3388,10 @@ pub async fn validate_transition_tier(lc: &BucketLifecycleConfiguration) -> Resu
    Ok(())
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 fn mark_delete_opts_skip_decommissioned_on_remote_success(opts: &mut ObjectOptions, remote_delete_succeeded: bool) {
    if remote_delete_succeeded {
        opts.skip_decommissioned = true;
@@ -4341,6 +4379,10 @@ pub async fn expire_transitioned_object(
    Ok(dobj)
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub fn gen_transition_objname(bucket: &str) -> Result<String, Error> {
    let us = Uuid::new_v4().to_string();
    let mut hasher = Sha256::new();
@@ -4375,6 +4417,10 @@ pub async fn transition_object(api: Arc<ECStore>, oi: &ObjectInfo, lae: LcAuditE
    result
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub fn audit_tier_actions(_tier: &str, bytes: i64) -> TimeFn {
    let tier = _tier.to_string();
    Arc::new(move || {
@@ -4393,6 +4439,10 @@ pub fn audit_tier_actions(_tier: &str, bytes: i64) -> TimeFn {
    })
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub async fn get_transitioned_object_reader(
    bucket: &str,
    object: &str,
@@ -4400,9 +4450,10 @@ pub async fn get_transitioned_object_reader(
    h: &HeaderMap,
    oi: &ObjectInfo,
    opts: &ObjectOptions,
+    resolver: Option<&dyn ObjectEncryptionResolver>,
 ) -> Result<GetObjectReader, std::io::Error> {
    let tier_config_mgr = runtime_sources::tier_config_mgr_handle();
-    get_transitioned_object_reader_with_tier_manager(bucket, object, rs, h, oi, opts, &tier_config_mgr).await
+    get_transitioned_object_reader_with_tier_manager(bucket, object, rs, h, oi, opts, &tier_config_mgr, resolver).await
 }

 fn validate_transition_remote_version(oi: &ObjectInfo) -> Result<bool, std::io::Error> {
@@ -4422,6 +4473,10 @@ fn validate_transition_remote_version(oi: &ObjectInfo) -> Result<bool, std::io::
    }
 }

+// The resolver joins the tier manager as the second injected port this read
+// needs; grouping the request half into a struct would churn every call site of
+// a bug fix.
+#[allow(clippy::too_many_arguments)]
 pub(crate) async fn get_transitioned_object_reader_with_tier_manager(
    bucket: &str,
    object: &str,
@@ -4430,6 +4485,7 @@ pub(crate) async fn get_transitioned_object_reader_with_tier_manager(
    oi: &ObjectInfo,
    opts: &ObjectOptions,
    tier_config_mgr: &Arc<RwLock<TierConfigMgr>>,
+    resolver: Option<&dyn ObjectEncryptionResolver>,
 ) -> Result<GetObjectReader, std::io::Error> {
    validate_transition_remote_version(oi)?;
    let expected_identity = tier_destination_id_from_metadata(&oi.user_defined)?;
@@ -4447,11 +4503,16 @@ pub(crate) async fn get_transitioned_object_reader_with_tier_manager(

    tgt_client.validate_remote_version_id(&oi.transitioned_object.version_id)?;

-    let ret = new_getobjectreader(rs, oi, opts, h);
-    if let Err(err) = ret {
-        return Err(error_resp_to_object_err(err, vec![bucket, object]));
-    }
-    let (get_fn, off, length) = ret.expect("get_transitioned_object_reader should succeed after error check");
+    // The same read plan the local path uses, so the tier fetch is positioned in
+    // the object's *stored* coordinate system and the stream is handed the same
+    // decrypt/decompress transforms. Reading an encrypted object's ciphertext
+    // through a plaintext-coordinate range and skipping the transform is how a
+    // transitioned SSE object used to come back as silently corrupt bytes of the
+    // right length (rustfs/rustfs#6025).
+    let plan = ReadPlan::build_for_request(rs.clone(), oi, opts, h, resolver)
+        .await
+        .map_err(|err| std::io::Error::other(format!("building the read plan for {bucket}/{object} failed: {err}")))?;
+    let (off, length) = (plan.storage_offset() as i64, plan.storage_length());
    let mut gopts = WarmBackendGetOpts::default();

    if off >= 0 && length >= 0 {
@@ -4488,7 +4549,10 @@ pub(crate) async fn get_transitioned_object_reader_with_tier_manager(
            );
            e
        })?;
-    Ok(attach_tier_operation_lease(get_fn(reader, h.clone()), tgt_client))
+    let object_reader = plan
+        .into_object_reader(Box::new(reader), oi)
+        .map_err(|err| std::io::Error::other(format!("wrapping the tier stream for {bucket}/{object} failed: {err}")))?;
+    Ok(attach_tier_operation_lease(object_reader, tgt_client))
 }

 struct TierOperationLeaseReader {
@@ -5133,6 +5197,10 @@ async fn lifecycle_delete_config_snapshot(api: &ECStore, oi: &ObjectInfo) -> Res
    ReplicationObjectBridge::delete_request_config(api, &oi.bucket).await
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub async fn apply_lifecycle_action(event: &lifecycle::Event, src: &LcEventSrc, oi: &ObjectInfo) -> bool {
    let mut success = false;
    match event.action {
@@ -5776,6 +5844,7 @@ mod tests {
            &object_info,
            &ObjectOptions::default(),
            &manager,
+            None,
        )
        .await
        .expect("transitioned reader should open");
@@ -5840,6 +5909,7 @@ mod tests {
            &object_info,
            &ObjectOptions::default(),
            &manager,
+            None,
        )
        .await
        {
@@ -5880,6 +5950,7 @@ mod tests {
            &object_info,
            &ObjectOptions::default(),
            &manager,
+            None,
        )
        .await
        {
@@ -6117,6 +6188,7 @@ mod tests {
            &oi,
            &ObjectOptions::default(),
            &manager,
+            None,
        )
        .await
        {
@@ -6140,6 +6212,7 @@ mod tests {
            &oi,
            &ObjectOptions::default(),
            &manager,
+            None,
        )
        .await
        {
@@ -7405,6 +7478,10 @@ mod tests {
    // process environment while `env::set_var`/`env::remove_var` is active.
    // SAFETY: keep this note adjacent to the allowance for the repository guard.
    #[allow(unsafe_code)]
+    #[allow(
+        dead_code,
+        reason = "transition-queue env fixture kept for tests that scope those vars; no test uses it today (backlog#1823)"
+    )]
    async fn with_transition_queue_env_async<F, Fut>(capacity: Option<&str>, timeout_ms: Option<&str>, test_fn: F)
    where
        F: FnOnce() -> Fut,
@@ -759,6 +759,10 @@ pub struct ManualTransitionWorkerResultRecord {
 }

 impl ManualTransitionWorkerResultRecord {
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+    )]
    pub fn new(job_id: Uuid, task_key: impl Into<String>, result: ManualTransitionWorkerResult) -> Self {
        Self::new_with_reason(job_id, task_key, result, None)
    }
@@ -1257,6 +1261,10 @@ pub(crate) async fn save_manual_transition_task_if_absent(
    }
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub async fn load_manual_transition_task_record(
    api: Arc<ECStore>,
    job_id: Uuid,
@@ -1320,6 +1328,10 @@ async fn scan_manual_transition_task_journal(api: Arc<ECStore>, job_id: Uuid) ->
    }
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub async fn load_manual_transition_worker_result_stats(
    api: Arc<ECStore>,
    job_id: Uuid,
@@ -1455,6 +1467,10 @@ async fn scan_manual_transition_worker_result_journal(
    }
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub async fn reconcile_manual_transition_worker_results(
    api: Arc<ECStore>,
    job_id: Uuid,
@@ -15,25 +15,35 @@
 use rustfs_common::metrics::IlmAction;

 use crate::bucket::lifecycle::lifecycle::ObjectOpts;
+use crate::bucket::replication::ReplicationLifecycleBridge;
 pub(crate) use crate::bucket::replication::ReplicationStatusType;
 #[cfg(test)]
 pub(crate) use crate::bucket::replication::VersionPurgeStatusType;
 pub(crate) use crate::bucket::replication::{
    DeleteReplicationConfigSnapshot, ReplicationObjectBridge, replication_state_to_filemeta,
 };
-use crate::bucket::replication::{ReplicationLifecycleBridge, ReplicationLifecycleConfig};
 use crate::storage_api_contracts::object::DeletedObject;

-pub(crate) type LifecycleReplicationConfig = ReplicationLifecycleConfig;
-
+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) fn has_pending_version_purge(obj: &ObjectOpts) -> bool {
    obj.version_purge_status.is_pending()
 }

+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) fn has_pending_object_replication(obj: &ObjectOpts) -> bool {
    replication_status_blocks_lifecycle(&obj.replication_status)
 }

+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) fn has_pending_lifecycle_replication(obj: &ObjectOpts) -> bool {
    has_pending_object_replication(obj) || has_pending_version_purge(obj)
 }
@@ -14,6 +14,10 @@

 use std::collections::HashMap;

+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) fn decode_tags_to_map(tags: &str) -> HashMap<String, String> {
    crate::bucket::tagging::decode_tags_to_map(tags)
 }
@@ -331,6 +331,10 @@ where
    persist_tier_delete_journal_entry(api, &committed).await
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub async fn abort_tier_delete_journal_entry<S>(api: Arc<S>, je: &Jentry) -> std::io::Result<()>
 where
    S: ObjectOperations<
@@ -148,6 +148,10 @@ struct RecoveryCursor {
    object: String,
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub async fn recover_tier_free_versions(
    api: Arc<ECStore>,
    limit: usize,
@@ -385,6 +385,10 @@ impl ExpiryOp for Jentry {
    }
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub async fn delete_object_from_remote_tier(obj_name: &str, rv_id: &str, tier_name: &str) -> Result<(), std::io::Error> {
    let result = delete_object_from_remote_tier_raw(obj_name, rv_id, tier_name).await;
    if let Err(err) = &result
@@ -395,6 +399,10 @@ pub async fn delete_object_from_remote_tier(obj_name: &str, rv_id: &str, tier_na
    result
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 async fn delete_object_from_remote_tier_raw(obj_name: &str, rv_id: &str, tier_name: &str) -> Result<(), std::io::Error> {
    #[cfg(test)]
    if let Some(result) = run_remote_tier_delete_test_hook(obj_name, rv_id, tier_name) {
@@ -405,6 +413,10 @@ async fn delete_object_from_remote_tier_raw(obj_name: &str, rv_id: &str, tier_na
    delete_object_from_remote_tier_raw_with_manager(obj_name, rv_id, tier_name, &tier_config_mgr).await
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 async fn delete_object_from_remote_tier_raw_with_manager(
    obj_name: &str,
    rv_id: &str,
@@ -485,6 +497,10 @@ pub enum RemoteTierDeleteOutcome {
    AlreadyRemoved,
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+)]
 pub async fn delete_object_from_remote_tier_idempotent(
    obj_name: &str,
    rv_id: &str,
@@ -50,8 +50,16 @@ pub type Result<T> = std::result::Result<T, TransitionTransactionError>;
 #[derive(Debug, thiserror::Error)]
 pub enum TransitionTransactionError {
    #[error("transition transaction already exists")]
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+    )]
    AlreadyExists,
    #[error("transition transaction is not found")]
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity tier/lifecycle entry point that this port never wired (backlog#1823)"
+    )]
    NotFound,
    #[error("transition transaction is corrupt: {0}")]
    Corrupt(&'static str),
@@ -50,6 +50,75 @@ use uuid::Uuid;

 const BUCKET_METADATA_REFRESH_INTERVAL: Duration = Duration::from_secs(15 * 60);

+#[cfg(any(test, feature = "test-util"))]
+struct ConfigWriteLockProbeState {
+    bucket: String,
+    arrived: tokio::sync::Notify,
+}
+
+#[cfg(any(test, feature = "test-util"))]
+static CONFIG_WRITE_LOCK_PROBES: std::sync::OnceLock<StdMutex<Vec<Arc<ConfigWriteLockProbeState>>>> = std::sync::OnceLock::new();
+
+#[cfg(any(test, feature = "test-util"))]
+#[allow(dead_code, reason = "installed by tests behind `--features test-util` (backlog#1823)")]
+pub struct ConfigWriteLockProbe {
+    state: Arc<ConfigWriteLockProbeState>,
+}
+
+#[cfg(any(test, feature = "test-util"))]
+impl ConfigWriteLockProbe {
+    #[allow(dead_code, reason = "installed by tests behind `--features test-util` (backlog#1823)")]
+    pub fn install(bucket: &str) -> Self {
+        let state = Arc::new(ConfigWriteLockProbeState {
+            bucket: bucket.to_string(),
+            arrived: tokio::sync::Notify::new(),
+        });
+        let mut probes = CONFIG_WRITE_LOCK_PROBES
+            .get_or_init(|| StdMutex::new(Vec::new()))
+            .lock()
+            .expect("config write lock probe mutex should not poison");
+        assert!(
+            !probes.iter().any(|current| current.bucket == state.bucket),
+            "config write lock probe must be unique for a bucket"
+        );
+        probes.push(Arc::clone(&state));
+        drop(probes);
+        Self { state }
+    }
+
+    #[allow(dead_code, reason = "installed by tests behind `--features test-util` (backlog#1823)")]
+    pub async fn wait_until_attempted(&self) {
+        tokio::time::timeout(Duration::from_secs(30), self.state.arrived.notified())
+            .await
+            .expect("bucket config update should attempt the transaction lock");
+    }
+}
+
+#[cfg(any(test, feature = "test-util"))]
+impl Drop for ConfigWriteLockProbe {
+    fn drop(&mut self) {
+        let mut probes = CONFIG_WRITE_LOCK_PROBES
+            .get_or_init(|| StdMutex::new(Vec::new()))
+            .lock()
+            .expect("config write lock probe mutex should not poison");
+        probes.retain(|state| !Arc::ptr_eq(state, &self.state));
+    }
+}
+
+#[cfg(any(test, feature = "test-util"))]
+fn notify_config_write_lock_attempt(bucket: &str) {
+    let probe = CONFIG_WRITE_LOCK_PROBES
+        .get_or_init(|| StdMutex::new(Vec::new()))
+        .lock()
+        .expect("config write lock probe mutex should not poison")
+        .iter()
+        .find(|probe| probe.bucket == bucket)
+        .cloned();
+    if let Some(probe) = probe {
+        probe.arrived.notify_one();
+    }
+}
+
 #[derive(Clone, Copy)]
 enum MetadataLoadMode {
    Initial,
@@ -590,6 +659,41 @@ pub async fn update_under_transaction_lock(
    update_under_config_write_guard(get_bucket_metadata_sys()?, guard, config_file, data).await
 }

+/// Clear one config file while the caller holds this bucket's transaction lock.
+pub async fn delete_under_transaction_lock(
+    guard: &BucketMetadataMutationGuard,
+    bucket: &str,
+    config_file: &str,
+) -> Result<OffsetDateTime> {
+    guard.ensure_valid(bucket)?;
+    delete_under_config_write_guard(get_bucket_metadata_sys()?, guard, config_file).await
+}
+
+pub async fn update_quota_if_incarnation(
+    bucket: &str,
+    data: Vec<u8>,
+    expected_incarnation_id: Uuid,
+    proof: &crate::services::notification_sys::CrossPoolFenceFleetProofToken,
+) -> Result<OffsetDateTime> {
+    let sys = get_bucket_metadata_sys()?;
+    let guard = Box::pin(acquire_config_write_guard_for_incarnation(
+        sys.clone(),
+        bucket,
+        Some(expected_incarnation_id),
+    ))
+    .await?;
+    if !crate::services::notification_sys::cross_pool_fence_fleet_proof_matches(proof) {
+        return Err(Error::NamespaceLockQuorumUnavailable {
+            mode: "quota_capability",
+            bucket: bucket.to_string(),
+            object: rustfs_config::QUOTA_CONFIG_FILE.to_string(),
+            required: 1,
+            achieved: 0,
+        });
+    }
+    update_under_config_write_guard(sys, &guard, rustfs_config::QUOTA_CONFIG_FILE, data).await
+}
+
 pub async fn update_bucket_targets_under_transaction_lock(
    guard: &BucketMetadataMutationGuard,
    bucket: &str,
@@ -704,6 +808,14 @@ pub async fn acquire_bucket_metadata_transaction_lock(bucket: &str) -> Result<Bu
    acquire_config_write_guard(get_bucket_metadata_sys()?, bucket).await
 }

+/// Acquire the bucket transaction lock only if its incarnation still matches.
+pub async fn acquire_bucket_metadata_transaction_lock_for_incarnation(
+    bucket: &str,
+    expected_incarnation_id: Uuid,
+) -> Result<BucketMetadataMutationGuard> {
+    acquire_config_write_guard_for_incarnation(get_bucket_metadata_sys()?, bucket, Some(expected_incarnation_id)).await
+}
+
 pub(crate) async fn acquire_bucket_metadata_transaction_lock_in(
    ctx: &crate::runtime::instance::InstanceContext,
    bucket: &str,
@@ -734,7 +846,26 @@ async fn acquire_transaction_lock_with_sys(
    let lock = api
        .new_ns_lock(RUSTFS_META_BUCKET, &bucket_metadata_transaction_lock_key(bucket))
        .await?;
-    Ok(lock.get_write_lock(crate::set_disk::get_lock_acquire_timeout()).await?)
+    let acquire = lock.get_write_lock(crate::set_disk::get_lock_acquire_timeout());
+    #[cfg(any(test, feature = "test-util"))]
+    {
+        tokio::pin!(acquire);
+        let mut notified = false;
+        let guard = futures::future::poll_fn(|cx| match std::future::Future::poll(acquire.as_mut(), cx) {
+            std::task::Poll::Pending => {
+                if !notified {
+                    notify_config_write_lock_attempt(bucket);
+                    notified = true;
+                }
+                std::task::Poll::Pending
+            }
+            std::task::Poll::Ready(result) => std::task::Poll::Ready(result),
+        })
+        .await?;
+        Ok(guard)
+    }
+    #[cfg(not(any(test, feature = "test-util")))]
+    Ok(acquire.await?)
 }

 /// The lock resource name is deliberately still the `bucket-targets` one it
@@ -762,6 +893,10 @@ pub async fn get_bucket_policy_raw(bucket: &str) -> Result<(String, OffsetDateTi
    bucket_meta_sys.get_bucket_policy_raw(bucket).await
 }

+#[allow(
+    dead_code,
+    reason = "free-function facade over the live BucketMetadataSys::get_bucket_acl_config; no caller in this port (backlog#1823)"
+)]
 pub async fn get_bucket_acl_config(bucket: &str) -> Result<(String, OffsetDateTime)> {
    let bucket_meta_sys_lock = get_bucket_metadata_sys()?;
    let bucket_meta_sys = bucket_meta_sys_lock.read().await;
@@ -889,6 +1024,37 @@ pub(crate) async fn get_object_lock_config_and_incarnation_from_disk_in(
    }
 }

+/// Re-read the quota configuration and bucket incarnation from the same
+/// authoritative metadata blob while the caller holds the bucket metadata
+/// transaction read lock.
+pub(crate) async fn get_quota_config_and_incarnation_from_disk_in(
+    ctx: &crate::runtime::instance::InstanceContext,
+    bucket: &str,
+) -> Result<(Option<BucketQuota>, Uuid, OffsetDateTime)> {
+    let bucket_meta_sys_lock = bucket_metadata_sys_of(ctx)?;
+    let bucket_meta_sys = bucket_meta_sys_lock.read().await.clone();
+
+    match bucket_meta_sys
+        .read_authoritative_metadata_from_disk_under_transaction_lock(bucket)
+        .await?
+    {
+        BucketMetadataAuthority::Authoritative(metadata)
+            if metadata.bucket_incarnation_sidecar && !metadata.bucket_incarnation_id.is_nil() =>
+        {
+            Ok((
+                metadata.quota_config.clone(),
+                metadata.bucket_incarnation_id,
+                metadata.quota_config_updated_at,
+            ))
+        }
+        BucketMetadataAuthority::Authoritative(_) => {
+            Err(Error::other(format!("bucket incarnation metadata is not authoritative: {bucket}")))
+        }
+        BucketMetadataAuthority::MissingBucket => Err(Error::BucketNotFound(bucket.to_string())),
+        BucketMetadataAuthority::Fabricated => Err(Error::other(format!("bucket quota metadata is not authoritative: {bucket}"))),
+    }
+}
+
 pub async fn get_replication_config(bucket: &str) -> Result<(ReplicationConfiguration, OffsetDateTime)> {
    let bucket_meta_sys_lock = get_bucket_metadata_sys()?;
    let bucket_meta_sys = bucket_meta_sys_lock.read().await;
@@ -945,6 +1111,10 @@ pub async fn get_config_from_disk(bucket: &str) -> Result<BucketMetadata> {
    bucket_meta_sys.get_config_from_disk(bucket).await
 }

+#[allow(
+    dead_code,
+    reason = "ambient-facade variant of the live created_at_in; no caller in this port (backlog#1823)"
+)]
 pub async fn created_at(bucket: &str) -> Result<OffsetDateTime> {
    let bucket_meta_sys_lock = get_bucket_metadata_sys()?;
    let bucket_meta_sys = bucket_meta_sys_lock.read().await;
@@ -1458,6 +1628,7 @@ impl BucketMetadataSys {
    /// [`Self::update`], with the payload computed from the loaded metadata
    /// instead of supplied up front. Loads through this system's own store so
    /// the read and the persisted write target the same instance.
+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    async fn update_config_with<F>(&self, bucket: &str, config_file: &str, mutate: F) -> Result<OffsetDateTime>
    where
        F: FnOnce(&BucketMetadata) -> Result<Vec<u8>> + Send,
@@ -1562,6 +1733,7 @@ impl BucketMetadataSys {
    /// A miss is never published as an authoritative default, and a snapshot
    /// read before delete plus same-name recreation cannot replace the new
    /// generation.
+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    pub(crate) async fn reload_from_store(&self, bucket: &str) -> Result<()> {
        if is_meta_bucketname(bucket) {
            return Err(Error::other("errInvalidArgument"));
@@ -13,7 +13,6 @@
 // limitations under the License.

 // #730: bucket subsystems still contain staged ECStore migration code.
-#![allow(dead_code)]

 pub mod bandwidth;
 pub mod bucket_target_sys;
@@ -136,6 +136,7 @@ pub fn add_years(dt: OffsetDateTime, years: i32) -> OffsetDateTime {

 /// Check if an object has legal hold enabled.
 /// Returns true if legal hold is ON.
+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 fn has_legal_hold(user_defined: &std::collections::HashMap<String, String>) -> bool {
    let lhold = objectlock::get_object_legalhold_meta(user_defined);
    matches!(lhold.status, Some(ref st) if st.as_str() == ObjectLockLegalHoldStatus::ON)
@@ -151,6 +152,7 @@ fn has_legal_hold(user_defined: &std::collections::HashMap<String, String>) -> b
 /// # Returns
 /// * `true` if the object is locked (cannot be deleted/modified)
 /// * `false` if the object is not locked
+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 pub fn is_object_locked_by_metadata(user_defined: &std::collections::HashMap<String, String>, is_delete_marker: bool) -> bool {
    // Delete markers are never locked
    if is_delete_marker {
@@ -52,6 +52,7 @@ impl QuotaChecker {
    ) -> Result<QuotaCheckResult, QuotaError> {
        let start_time = Instant::now();
        let quota_config = self.get_quota_config(bucket).await?;
+        let uses_durable_reservations = quota_config.uses_durable_reservations();

        // If no quota limit is set, allow operation
        let quota_limit = match quota_config.quota {
@@ -67,6 +68,7 @@ impl QuotaChecker {
                    quota_limit: None,
                    operation_size,
                    remaining: None,
+                    uses_durable_reservations,
                });
            }
            Some(q) => q,
@@ -74,14 +76,17 @@ impl QuotaChecker {

        let current_usage = self.get_real_time_usage(bucket).await?;

+        let admission_size = if uses_durable_reservations { 0 } else { operation_size };
        let expected_usage = match operation {
-            QuotaOperation::PutObject | QuotaOperation::PostObject | QuotaOperation::CopyObject => current_usage + operation_size,
+            QuotaOperation::PutObject | QuotaOperation::PostObject | QuotaOperation::CopyObject => {
+                current_usage.saturating_add(admission_size)
+            }
            QuotaOperation::DeleteObject => current_usage.saturating_sub(operation_size),
        };

        let allowed = match operation {
            QuotaOperation::PutObject | QuotaOperation::PostObject | QuotaOperation::CopyObject => {
-                quota_config.check_operation_allowed(current_usage, operation_size)
+                quota_config.check_operation_allowed(current_usage, admission_size)
            }
            QuotaOperation::DeleteObject => true,
        };
@@ -105,6 +110,7 @@ impl QuotaChecker {
            quota_limit: Some(quota_limit),
            operation_size,
            remaining,
+            uses_durable_reservations,
        };

        let duration = start_time.elapsed();
@@ -158,6 +164,26 @@ impl QuotaChecker {
            .await
    }

+    pub async fn set_durable_quota_config_if_incarnation(
+        &mut self,
+        bucket: &str,
+        quota: BucketQuota,
+        expected_incarnation_id: uuid::Uuid,
+        proof: &crate::services::notification_sys::CrossPoolFenceFleetProofToken,
+    ) -> Result<OffsetDateTime, QuotaError> {
+        let json_data = serde_json::to_vec(&quota).map_err(|e| QuotaError::InvalidConfig {
+            reason: format!("Failed to serialize quota config: {}", e),
+        })?;
+        let start_time = Instant::now();
+        let updated_at =
+            crate::bucket::metadata_sys::update_quota_if_incarnation(bucket, json_data, expected_incarnation_id, proof)
+                .await
+                .map_err(QuotaError::StorageError)?;
+
+        rustfs_common::metrics::Metrics::inc_time(Metric::QuotaSync, start_time.elapsed());
+        Ok(updated_at)
+    }
+
    async fn set_quota_config_for_incarnation(
        &mut self,
        bucket: &str,
@@ -355,6 +381,7 @@ mod tests {
            quota_limit: None,
            operation_size: 1024,
            remaining: None,
+            uses_durable_reservations: false,
        };

        assert!(result.allowed);
@@ -378,4 +405,13 @@ mod tests {
        let allowed = quota.check_operation_allowed(512, 1024);
        assert!(!allowed);
    }
+
+    #[test]
+    fn legacy_quota_rejects_full_operation_while_v1_defers_net_growth() {
+        let legacy: BucketQuota = serde_json::from_str(r#"{"quota":5}"#).expect("legacy quota should parse");
+        let durable = BucketQuota::new(Some(5));
+
+        assert!(!legacy.check_operation_allowed(4, 2));
+        assert!(durable.uses_durable_reservations());
+    }
 }
@@ -13,40 +13,100 @@
 // limitations under the License.

 pub mod checker;
+pub(crate) mod reservation;

 use crate::error::Result;
 use rustfs_config::{
    QUOTA_API_PATH, QUOTA_EXCEEDED_ERROR_CODE, QUOTA_INTERNAL_ERROR_CODE, QUOTA_INVALID_CONFIG_ERROR_CODE,
    QUOTA_NOT_FOUND_ERROR_CODE,
 };
-use serde::{Deserialize, Serialize};
+use serde::{Deserialize, Deserializer, Serialize, Serializer, de::Error as _};
 use thiserror::Error;
 use time::OffsetDateTime;

 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, Default)]
 pub enum QuotaType {
-    /// Hard quota: reject immediately when exceeded
+    /// Hard quota accounting.
    #[default]
    #[serde(alias = "HARD", alias = "hard")]
    Hard,
 }

+pub(crate) const QUOTA_RESERVATION_PROTOCOL_V1: u32 = 1;
+
 /// Bucket quota configuration. quota_type defaults to Hard when omitted.
-#[derive(Debug, Deserialize, Serialize, Default, Clone, PartialEq)]
+#[derive(Debug, Default, Clone, PartialEq)]
 pub struct BucketQuota {
-    #[serde(default)]
    pub quota: Option<u64>,
    /// Defaults to Hard when missing.
-    #[serde(default)]
    pub quota_type: QuotaType,
+    /// Optional durable reservation protocol. The wire format gives older
+    /// nodes a zero hard quota so a mixed-version fleet fails closed.
+    pub reservation_protocol: Option<u32>,
    /// Timestamp when this quota configuration was set (for audit purposes)
-    #[serde(default, with = "time::serde::rfc3339::option")]
    pub created_at: Option<OffsetDateTime>,
    /// Accept updated_at for compatibility; not used.
-    #[serde(default, with = "time::serde::rfc3339::option", skip_serializing_if = "Option::is_none")]
    pub updated_at: Option<OffsetDateTime>,
 }

+#[derive(Deserialize, Serialize)]
+struct BucketQuotaWire {
+    #[serde(default)]
+    quota: Option<u64>,
+    #[serde(default)]
+    quota_type: QuotaType,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    reservation_protocol: Option<u32>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    reservation_quota: Option<u64>,
+    #[serde(default, with = "time::serde::rfc3339::option")]
+    created_at: Option<OffsetDateTime>,
+    #[serde(default, with = "time::serde::rfc3339::option", skip_serializing_if = "Option::is_none")]
+    updated_at: Option<OffsetDateTime>,
+}
+
+impl Serialize for BucketQuota {
+    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let durable = self.uses_durable_reservations();
+        BucketQuotaWire {
+            quota: if durable { Some(0) } else { self.quota },
+            quota_type: self.quota_type.clone(),
+            reservation_protocol: self.reservation_protocol,
+            reservation_quota: if durable { self.quota } else { None },
+            created_at: self.created_at,
+            updated_at: self.updated_at,
+        }
+        .serialize(serializer)
+    }
+}
+
+impl<'de> Deserialize<'de> for BucketQuota {
+    fn deserialize<D>(deserializer: D) -> std::result::Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let wire = BucketQuotaWire::deserialize(deserializer)?;
+        let quota = if wire.reservation_protocol == Some(QUOTA_RESERVATION_PROTOCOL_V1) {
+            Some(
+                wire.reservation_quota
+                    .ok_or_else(|| D::Error::custom("reservation_quota is required for reservation protocol v1"))?,
+            )
+        } else {
+            wire.quota
+        };
+        Ok(Self {
+            quota,
+            quota_type: wire.quota_type,
+            reservation_protocol: wire.reservation_protocol,
+            created_at: wire.created_at,
+            updated_at: wire.updated_at,
+        })
+    }
+}
+
 impl BucketQuota {
    /// Serialize to JSON bytes. Same format as parse_all_configs.
    pub fn marshal_msg(&self) -> Result<Vec<u8>> {
@@ -63,6 +123,7 @@ impl BucketQuota {
        Self {
            quota,
            quota_type: QuotaType::Hard,
+            reservation_protocol: quota.map(|_| QUOTA_RESERVATION_PROTOCOL_V1),
            created_at: Some(now),
            updated_at: None,
        }
@@ -72,7 +133,19 @@ impl BucketQuota {
        self.quota
    }

+    pub fn uses_durable_reservations(&self) -> bool {
+        self.reservation_protocol == Some(QUOTA_RESERVATION_PROTOCOL_V1)
+    }
+
+    pub fn has_unsupported_reservation_protocol(&self) -> bool {
+        self.reservation_protocol
+            .is_some_and(|version| version != QUOTA_RESERVATION_PROTOCOL_V1)
+    }
+
    pub fn check_operation_allowed(&self, current_usage: u64, operation_size: u64) -> bool {
+        if operation_size == 0 {
+            return true;
+        }
        if let Some(quota_limit) = self.quota {
            current_usage.saturating_add(operation_size) <= quota_limit
        } else {
@@ -94,6 +167,7 @@ pub struct QuotaCheckResult {
    pub quota_limit: Option<u64>,
    pub operation_size: u64,
    pub remaining: Option<u64>,
+    pub uses_durable_reservations: bool,
 }

 #[derive(Debug)]
@@ -119,6 +193,7 @@ pub enum QuotaError {
 }

 #[derive(Debug, Serialize)]
+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 pub struct QuotaErrorResponse {
    #[serde(rename = "Code")]
    pub code: String,
@@ -134,6 +209,7 @@ pub struct QuotaErrorResponse {
 }

 impl QuotaErrorResponse {
+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    pub fn new(quota_error: &QuotaError, request_id: &str, host_id: &str) -> Self {
        match quota_error {
            QuotaError::QuotaExceeded { .. } => Self {
@@ -210,7 +286,59 @@ mod tests {
        let buf = q.marshal_msg().expect("marshal");
        let restored = BucketQuota::unmarshal(&buf).expect("unmarshal");
        assert_eq!(q.quota, restored.quota);
-        assert_eq!(q.quota_type, restored.quota_type);
+        assert_eq!(restored.quota_type, QuotaType::Hard);
+        assert_eq!(restored.reservation_protocol, Some(QUOTA_RESERVATION_PROTOCOL_V1));
+    }
+
+    #[test]
+    fn clearing_quota_keeps_the_legacy_compatible_type() {
+        let quota = BucketQuota::new(None);
+
+        assert_eq!(quota.quota_type, QuotaType::Hard);
+        assert_eq!(quota.reservation_protocol, None);
+        assert!(!quota.uses_durable_reservations());
+    }
+
+    #[test]
+    fn durable_quota_makes_legacy_nodes_fail_closed() {
+        let json = serde_json::to_vec(&BucketQuota::new(Some(2048))).expect("durable quota should serialize");
+        let quota: BucketQuota = serde_json::from_slice(&json).expect("current quota version should parse");
+        assert!(quota.uses_durable_reservations());
+        assert_eq!(quota.quota, Some(2048));
+
+        #[derive(Deserialize)]
+        enum LegacyQuotaType {
+            Hard,
+        }
+        #[derive(Deserialize)]
+        struct LegacyBucketQuota {
+            #[allow(dead_code)]
+            quota: Option<u64>,
+            #[allow(dead_code)]
+            quota_type: LegacyQuotaType,
+        }
+        let legacy = serde_json::from_slice::<LegacyBucketQuota>(&json)
+            .expect("legacy readers should ignore the reservation protocol field");
+        assert_eq!(legacy.quota, Some(0));
+        assert!(matches!(legacy.quota_type, LegacyQuotaType::Hard));
+    }
+
+    #[test]
+    fn unknown_reservation_protocol_does_not_activate_v1() {
+        let quota: BucketQuota =
+            serde_json::from_str(r#"{"quota":0,"quota_type":"Hard","reservation_protocol":2,"reservation_quota":2048}"#)
+                .expect("future protocol should remain parseable");
+
+        assert!(!quota.uses_durable_reservations());
+        assert!(quota.has_unsupported_reservation_protocol());
+    }
+
+    #[test]
+    fn reservation_protocol_v1_requires_reservation_quota() {
+        let err = serde_json::from_str::<BucketQuota>(r#"{"quota":0,"quota_type":"Hard","reservation_protocol":1}"#)
+            .expect_err("v1 without its authoritative quota must fail closed");
+
+        assert!(err.to_string().contains("reservation_quota is required"));
    }

    /// unmarshal accepts format without quota_type
@@ -60,7 +60,7 @@ pub use replication_filemeta_boundary::{
 pub(crate) use replication_filemeta_boundary::{
    replication_state_from_filemeta, replication_status_from_filemeta, version_purge_status_from_filemeta,
 };
-pub(crate) use replication_lifecycle_bridge::{ReplicationLifecycleBridge, ReplicationLifecycleConfig};
+pub(crate) use replication_lifecycle_bridge::ReplicationLifecycleBridge;
 pub(crate) use replication_migration_bridge::ReplicationMigrationBridge;
 pub use replication_object_bridge::ReplicationObjectBridge;
 pub use replication_object_config::{DeleteReplicationConfigSnapshot, ReplicationConfig};
@@ -81,6 +81,6 @@ pub use replication_queue_boundary::{
 pub use replication_resync_boundary::{BucketReplicationResyncStatus, ResyncOpts, TargetReplicationResyncStatus};
 pub use replication_scanner_bridge::ReplicationScannerBridge;
 pub use replication_state::{ReplicationStats, RuntimeReplicationTargetBacklog};
-pub use replication_stats_boundary::{BucketReplicationStats, BucketStats};
+pub use replication_stats_boundary::{BucketReplicationStat, BucketReplicationStats, BucketStats, InQueueMetric, XferStats};
 pub use replication_storage_boundary::{ReplicationObjectIO, ReplicationStorage};
 pub(crate) use replication_target_config_bridge::ReplicationTargetConfigBridge;
@@ -37,6 +37,10 @@ impl ReplicationConfigStore {
        com::read_config_limited(api, file, max_bytes).await
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    pub(crate) async fn read_no_lock<S>(api: Arc<S>, file: &str) -> Result<Vec<u8>>
    where
        S: ReplicationObjectIO,
@@ -24,15 +24,27 @@ use super::replication_storage_boundary::{
    DeletedObject, ObjectInfo, ObjectOptions, ObjectToDelete, deleted_object_for_replication,
 };

+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) type ReplicationLifecycleConfig = ReplicationConfig;

 pub(crate) struct ReplicationLifecycleBridge;

 impl ReplicationLifecycleBridge {
+    #[allow(
+        dead_code,
+        reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+    )]
    pub(crate) fn new_config(config: ReplicationConfiguration) -> ReplicationLifecycleConfig {
        ReplicationConfig::new(Some(config), None)
    }

+    #[allow(
+        dead_code,
+        reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+    )]
    pub(crate) fn has_pending_version_purge(
        config: &ReplicationLifecycleConfig,
        object_name: &str,
@@ -45,6 +57,10 @@ impl ReplicationLifecycleBridge {
                .is_some_and(|config| config.has_active_rules(object_name, true))
    }

+    #[allow(
+        dead_code,
+        reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+    )]
    pub(crate) async fn check_delete_replication(
        bucket: &str,
        object: &ObjectToDelete,
@@ -54,6 +70,10 @@ impl ReplicationLifecycleBridge {
        check_replicate_delete(bucket, object, source, opts, None).await
    }

+    #[allow(
+        dead_code,
+        reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+    )]
    pub(crate) fn version_delete_replication_state(decision: &ReplicateDecision) -> ReplicationState {
        let pending_status = decision.pending_status();
        ReplicationState {
@@ -19,17 +19,33 @@ use time::OffsetDateTime;
 use super::replication_error_boundary::Result;
 use crate::bucket::msgp_decode;

+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) struct ReplicationMsgpCodec;

 impl ReplicationMsgpCodec {
+    #[allow(
+        dead_code,
+        reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+    )]
    pub(crate) fn read_ext8_time<R: Read>(rd: &mut R) -> Result<OffsetDateTime> {
        msgp_decode::read_msgp_ext8_time(rd)
    }

+    #[allow(
+        dead_code,
+        reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+    )]
    pub(crate) fn skip_value<R: Read>(rd: &mut R) -> Result<()> {
        msgp_decode::skip_msgp_value(rd)
    }

+    #[allow(
+        dead_code,
+        reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+    )]
    pub(crate) fn write_time<W: Write>(wr: &mut W, time: OffsetDateTime) -> Result<()> {
        msgp_decode::write_msgp_time(wr, time)
    }
@@ -77,6 +77,10 @@ impl ReplicationObjectBridge {
        load_delete_request_config_in(ctx, bucket).await
    }

+    #[allow(
+        dead_code,
+        reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+    )]
    pub(crate) async fn delete_config_snapshot_in(
        ctx: &ReplicationInstanceContext,
        bucket: &str,
@@ -231,6 +231,10 @@ pub(crate) async fn load_delete_replication_config(
    delete_snapshot_from_metadata(ReplicationMetadataStore::delete_metadata(bucket).await?)
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+)]
 pub(crate) async fn load_delete_replication_config_in(
    ctx: &ReplicationInstanceContext,
    bucket: &str,
@@ -217,6 +217,10 @@ impl DurableMrfBacklogTracker {
    }
 }

+#[allow(
+    dead_code,
+    reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+)]
 fn durable_mrf_backlog_tracker_from_entries(entries: &[MrfReplicateEntry]) -> DurableMrfBacklogTracker {
    let mut tracker = DurableMrfBacklogTracker {
        available: true,
@@ -712,6 +716,10 @@ pub struct ReplicationPool<S: ReplicationStorage> {

    // MRF worker lifecycle
    mrf_worker_cancellations: Mutex<Vec<CancellationToken>>,
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    mrf_stop_tx: Sender<()>,

    // Worker size tracking
@@ -940,6 +948,10 @@ impl<S: ReplicationStorage> ReplicationPool<S> {
    }

    /// Resizes worker priority and counts
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    pub async fn resize_worker_priority(
        &self,
        pri: ReplicationPriority,
@@ -1180,6 +1192,10 @@ impl<S: ReplicationStorage> ReplicationPool<S> {
    }

    /// Queues an MRF save operation
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    async fn queue_mrf_save(&self, entry: MrfReplicateEntry) {
        let _ = self.queue_mrf_save_admission(entry, "mrf_worker").await;
    }
@@ -1651,6 +1667,10 @@ impl<S: ReplicationStorage> ReplicationPool<S> {
    }

    /// Worker function for handling regular replication operations
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    async fn add_worker(
        &self,
        mut rx: Receiver<ReplicationOperation>,
@@ -1664,6 +1684,10 @@ impl<S: ReplicationStorage> ReplicationPool<S> {
    }

    /// Worker function for handling large object replication operations
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    async fn add_large_worker(
        &self,
        mut rx: Receiver<ReplicationOperation>,
@@ -1678,6 +1702,10 @@ impl<S: ReplicationStorage> ReplicationPool<S> {
    }

    /// Worker function for handling MRF (Most Recent Failures) operations
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    async fn add_mrf_worker(
        &self,
        mut rx: Receiver<ReplicationOperation>,
@@ -1691,6 +1719,10 @@ impl<S: ReplicationStorage> ReplicationPool<S> {
    }

    /// Delete resync metadata from replication resync state in memory
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    pub async fn delete_resync_metadata(&self, bucket: &str) {
        let mut status_map = self.resyncer.status_map.write().await;
        status_map.remove(bucket);
@@ -21,11 +21,31 @@ pub(crate) use rustfs_replication::{
    should_count_head_proxy_failure,
 };

+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) const RESYNC_META_FORMAT: u16 = rustfs_replication::resync::RESYNC_META_FORMAT;
+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) const RESYNC_META_VERSION: u16 = rustfs_replication::resync::RESYNC_META_VERSION;
 pub(crate) const RESYNC_FILE_MAX_BYTES: usize = rustfs_replication::RESYNC_FILE_MAX_BYTES;
+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) const WIRE_ZERO_TIME_UNIX: i64 = rustfs_replication::resync::WIRE_ZERO_TIME_UNIX;
+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) const MRF_META_FORMAT: u16 = rustfs_replication::mrf::MRF_META_FORMAT;
+#[allow(
+    dead_code,
+    reason = "declared boundary surface for the ECStore replication split plan; no caller in this port (backlog#1823)"
+)]
 pub(crate) const MRF_META_VERSION: u16 = rustfs_replication::mrf::MRF_META_VERSION;

 fn map_replication_error(err: rustfs_replication::Error) -> Error {
@@ -122,6 +122,10 @@ const REPLICATION_TARGET_OFFLINE_ERROR_MARKERS: &[&str] = &[
    "tcp connect error",
 ];

+#[allow(
+    dead_code,
+    reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+)]
 const RESYNC_TIME_INTERVAL: TokioDuration = TokioDuration::from_secs(60);

 static WARNED_MONITOR_UNINIT: std::sync::Once = std::sync::Once::new();
@@ -328,6 +332,10 @@ fn bounded_resync_max_jobs(value: usize) -> usize {
 #[derive(Debug)]
 pub struct ReplicationResyncer {
    pub status_map: Arc<RwLock<HashMap<String, BucketReplicationResyncStatus>>>,
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    pub worker_size: usize,
    pub(crate) cancel_tokens: Arc<RwLock<HashMap<ResyncCancelKey, CancellationToken>>>,
    resync_admission: Arc<Semaphore>,
@@ -544,6 +552,10 @@ impl ReplicationResyncer {
            .is_some_and(|status| status.failed_count > 0)
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    pub async fn persist_to_disk<S>(&self, cancel_token: CancellationToken, api: Arc<S>)
    where
        S: ReplicationObjectIO,
@@ -340,6 +340,10 @@ impl ReplicationStats {
    }

    /// Site replication update replica statistics
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity replication surface with no caller in this port (backlog#1823)"
+    )]
    fn sr_update_replica_stat(&self, size: i64) {
        self.sr_stats.replica_size.fetch_add(size, Ordering::Relaxed);
        self.sr_stats.replica_count.fetch_add(1, Ordering::Relaxed);
@@ -704,6 +708,12 @@ impl ReplicationStats {
        } else {
            BucketReplicationStats::new()
        };
+        // Stamp the serializable failure windows from the live samples: the
+        // samples themselves do not cross the peer-RPC wire, so this snapshot
+        // is what cluster aggregation and the metrics endpoints see.
+        for stat in replication_stats.stats.values_mut() {
+            stat.fail_stats.refresh_windows();
+        }
        let uptime = if cache.contains_key(bucket) {
            SystemTime::now()
                .duration_since(SystemTime::UNIX_EPOCH)
@@ -15,7 +15,9 @@
 #[cfg(test)]
 pub(crate) use rustfs_replication::FailStats;
 pub(crate) use rustfs_replication::{
-    ActiveWorkerStat, BucketReplicationStat, InQueueMetric, ProxyMetric, ProxyStatsCache, QueueCache, ReplicationMetricScope,
-    SRMetricsSummary, XferStats,
+    ActiveWorkerStat, ProxyMetric, ProxyStatsCache, QueueCache, ReplicationMetricScope, SRMetricsSummary,
 };
-pub use rustfs_replication::{BucketReplicationStats, BucketStats};
+// Public so the admin wire DTOs (rustfs/src/admin/replication_metrics_wire.rs)
+// can project the internal stats onto the minio-go response shapes through
+// the storage_api facade chain.
+pub use rustfs_replication::{BucketReplicationStat, BucketReplicationStats, BucketStats, InQueueMetric, XferStats};
@@ -27,8 +27,10 @@ use rustfs_utils::http::{
    AMZ_OBJECT_TAGGING, AMZ_SERVER_SIDE_ENCRYPTION, AMZ_SERVER_SIDE_ENCRYPTION_KMS_CONTEXT, AMZ_SERVER_SIDE_ENCRYPTION_KMS_ID,
    AMZ_STORAGE_CLASS, AMZ_TAG_COUNT, CACHE_CONTROL, CONTENT_DISPOSITION, CONTENT_ENCODING, CONTENT_LANGUAGE, CONTENT_TYPE,
    HeaderExt as _, SUFFIX_OBJECTLOCK_LEGALHOLD_TIMESTAMP, SUFFIX_OBJECTLOCK_RETENTION_TIMESTAMP,
-    SUFFIX_REPLICATION_ACTUAL_OBJECT_SIZE, SUFFIX_REPLICATION_SSEC_CRC, SUFFIX_TAGGING_TIMESTAMP, get_str, insert_header_map,
-    is_internal_key, is_object_encryption_marker, is_replication_stripped_encryption_key, ssec_replication_transport_header,
+    SUFFIX_REPLICATION_ACTUAL_OBJECT_SIZE, SUFFIX_REPLICATION_SSEC_CRC, SUFFIX_SOURCE_REPLICATION_LEGALHOLD_TIMESTAMP,
+    SUFFIX_SOURCE_REPLICATION_RETENTION_TIMESTAMP, SUFFIX_SOURCE_REPLICATION_TAGGING_TIMESTAMP, SUFFIX_TAGGING_TIMESTAMP,
+    get_str, insert_header_map, is_internal_key, is_object_encryption_marker, is_replication_stripped_encryption_key,
+    ssec_replication_transport_header,
 };
 use time::OffsetDateTime;
 use time::format_description::well_known::Rfc3339;
@@ -119,6 +121,27 @@ fn classify_replication_source_encryption(metadata: &HashMap<String, String>) ->
    }
 }

+fn is_legacy_source_replication_timestamp_key(key: &str) -> bool {
+    fn has_prefix_and_suffix(key: &str, prefix: &str, suffix: &str) -> bool {
+        let key = key.as_bytes();
+        key.len() == prefix.len() + suffix.len()
+            && key[..prefix.len()].eq_ignore_ascii_case(prefix.as_bytes())
+            && key[prefix.len()..].eq_ignore_ascii_case(suffix.as_bytes())
+    }
+
+    [
+        SUFFIX_SOURCE_REPLICATION_TAGGING_TIMESTAMP,
+        SUFFIX_SOURCE_REPLICATION_RETENTION_TIMESTAMP,
+        SUFFIX_SOURCE_REPLICATION_LEGALHOLD_TIMESTAMP,
+    ]
+    .iter()
+    .any(|suffix| {
+        ["x-rustfs-", "x-minio-"]
+            .iter()
+            .any(|prefix| has_prefix_and_suffix(key, prefix, suffix))
+    })
+}
+
 pub(crate) fn replication_object_is_ssec_encrypted(user_defined: &HashMap<String, String>) -> bool {
    rustfs_replication::is_ssec_encrypted(user_defined)
 }
@@ -176,6 +199,11 @@ pub(crate) fn replication_put_object_options(sc: &str, object_info: &ObjectInfo)
            continue;
        }

+        if is_legacy_source_replication_timestamp_key(key) {
+            meta.insert(format!("x-amz-meta-{key}"), value.to_string());
+            continue;
+        }
+
        if is_internal_key(key) || is_standard_header(key) {
            continue;
        }
@@ -259,15 +287,23 @@ pub(crate) fn replication_put_object_options(sc: &str, object_info: &ObjectInfo)

        if !tags.is_empty() {
            put_options.user_tags = tags;
-            put_options.internal.tagging_timestamp =
-                if let Some(timestamp) = get_str(&object_info.user_defined, SUFFIX_TAGGING_TIMESTAMP) {
-                    OffsetDateTime::parse(&timestamp, &Rfc3339)
-                        .map_err(|err| Error::other(format!("Failed to parse tagging timestamp: {err}")))?
-                } else {
-                    object_info.mod_time.unwrap_or(OffsetDateTime::UNIX_EPOCH)
-                };
        }
    }
+    // Load the stored tagging timestamp independently of whether any tags
+    // remain: DeleteObjectTagging leaves the object tagless but stamps this
+    // key, and the deletion's LWW timestamp must still reach the replica.
+    // With no stored key, fall back to mod_time only while tags exist
+    // (MinIO parity); a tagless object without the key was never tagged and
+    // keeps the epoch default (no header).
+    put_options.internal.tagging_timestamp = if let Some(timestamp) = get_str(&object_info.user_defined, SUFFIX_TAGGING_TIMESTAMP)
+    {
+        OffsetDateTime::parse(&timestamp, &Rfc3339)
+            .map_err(|err| Error::other(format!("Failed to parse tagging timestamp: {err}")))?
+    } else if !put_options.user_tags.is_empty() {
+        object_info.mod_time.unwrap_or(OffsetDateTime::UNIX_EPOCH)
+    } else {
+        OffsetDateTime::UNIX_EPOCH
+    };

    let metadata = &*object_info.user_defined;

@@ -283,13 +319,15 @@ pub(crate) fn replication_put_object_options(sc: &str, object_info: &ObjectInfo)
        put_options.cache_control = cache_control.to_string();
    }

-    if let Some(mode) = metadata.lookup(AMZ_OBJECT_LOCK_MODE) {
+    if let Some(mode) = metadata.lookup(AMZ_OBJECT_LOCK_MODE).filter(|mode| !mode.is_empty()) {
        put_options.mode = Some(ObjectLockRetentionMode::from(mode.to_uppercase().as_str()));
    }

    if let Some(retain_until_date) = metadata.lookup(AMZ_OBJECT_LOCK_RETAIN_UNTIL_DATE) {
-        put_options.retain_until_date = OffsetDateTime::parse(retain_until_date, &Rfc3339)
-            .map_err(|err| Error::other(format!("Failed to parse retain until date: {err}")))?;
+        if !retain_until_date.is_empty() {
+            put_options.retain_until_date = OffsetDateTime::parse(retain_until_date, &Rfc3339)
+                .map_err(|err| Error::other(format!("Failed to parse retain until date: {err}")))?;
+        }
        put_options.internal.retention_timestamp =
            if let Some(timestamp) = get_str(&object_info.user_defined, SUFFIX_OBJECTLOCK_RETENTION_TIMESTAMP) {
                OffsetDateTime::parse(&timestamp, &Rfc3339).unwrap_or(OffsetDateTime::UNIX_EPOCH)
@@ -694,6 +732,110 @@ mod tests {
        assert!(options.internal.replication_request);
    }

+    /// DeleteObjectTagging leaves the object tagless but stamps the
+    /// tagging-timestamp internal key; the deletion's LWW timestamp must
+    /// still be loaded (and therefore sent) so the replica can order the
+    /// deletion against concurrent tag edits.
+    #[test]
+    fn replication_put_options_carry_tagging_timestamp_after_tag_deletion() {
+        let mut metadata = std::collections::HashMap::new();
+        rustfs_utils::http::insert_str(&mut metadata, SUFFIX_TAGGING_TIMESTAMP, "2026-01-02T03:04:05Z".to_string());
+
+        let object_info = ObjectInfo {
+            user_defined: Arc::new(metadata),
+            user_tags: Arc::new(String::new()),
+            mod_time: Some(OffsetDateTime::UNIX_EPOCH),
+            version_id: Some(Uuid::nil()),
+            ..Default::default()
+        };
+
+        let (options, _) = replication_put_object_options("", &object_info).expect("build put options");
+
+        assert!(options.user_tags.is_empty());
+        assert_eq!(
+            options.internal.tagging_timestamp,
+            OffsetDateTime::parse("2026-01-02T03:04:05Z", &Rfc3339).expect("valid timestamp"),
+            "the stored tagging timestamp must load independently of remaining tags"
+        );
+
+        // A tagless object without the stored key was never tagged: the epoch
+        // default keeps the header unsent.
+        let untagged = ObjectInfo {
+            user_tags: Arc::new(String::new()),
+            mod_time: Some(OffsetDateTime::from_unix_timestamp(1_700_000_000).expect("timestamp")),
+            version_id: Some(Uuid::nil()),
+            ..Default::default()
+        };
+        let (options, _) = replication_put_object_options("", &untagged).expect("build put options");
+        assert_eq!(options.internal.tagging_timestamp, OffsetDateTime::UNIX_EPOCH);
+    }
+
+    #[test]
+    fn replication_put_options_do_not_promote_legacy_user_timestamp_metadata() {
+        let legacy_keys = [
+            "x-rustfs-source-replication-tagging-timestamp",
+            "x-rustfs-source-replication-retention-timestamp",
+            "x-rustfs-source-replication-legalhold-timestamp",
+            "x-minio-source-replication-tagging-timestamp",
+            "x-minio-source-replication-retention-timestamp",
+            "x-minio-source-replication-legalhold-timestamp",
+        ];
+        let object_info = ObjectInfo {
+            user_defined: Arc::new(
+                legacy_keys
+                    .iter()
+                    .map(|key| (key.to_string(), "2099-01-02T03:04:05Z".to_string()))
+                    .collect(),
+            ),
+            ..Default::default()
+        };
+
+        let (options, _) = replication_put_object_options("", &object_info).expect("build put options");
+
+        for legacy_key in legacy_keys {
+            assert!(!options.user_metadata.contains_key(legacy_key));
+            assert_eq!(
+                options
+                    .user_metadata
+                    .get(&format!("x-amz-meta-{legacy_key}"))
+                    .map(String::as_str),
+                Some("2099-01-02T03:04:05Z")
+            );
+        }
+        assert_eq!(options.internal.tagging_timestamp, OffsetDateTime::UNIX_EPOCH);
+        assert_eq!(options.internal.retention_timestamp, OffsetDateTime::UNIX_EPOCH);
+        assert_eq!(options.internal.legalhold_timestamp, OffsetDateTime::UNIX_EPOCH);
+    }
+
+    #[test]
+    fn replication_put_options_carry_retention_timestamp_after_clear() {
+        let mut metadata = HashMap::from([
+            (AMZ_OBJECT_LOCK_MODE.to_string(), String::new()),
+            (AMZ_OBJECT_LOCK_RETAIN_UNTIL_DATE.to_string(), String::new()),
+        ]);
+        rustfs_utils::http::insert_str(&mut metadata, SUFFIX_OBJECTLOCK_RETENTION_TIMESTAMP, "2026-01-02T03:04:05Z".to_string());
+        let object_info = ObjectInfo {
+            user_defined: Arc::new(metadata),
+            ..Default::default()
+        };
+
+        let (options, _) = replication_put_object_options("", &object_info).expect("retention clear must replicate");
+
+        assert!(options.mode.is_none());
+        assert_eq!(options.retain_until_date, OffsetDateTime::UNIX_EPOCH);
+        assert_eq!(
+            options.internal.retention_timestamp,
+            OffsetDateTime::parse("2026-01-02T03:04:05Z", &Rfc3339).expect("valid timestamp")
+        );
+        let headers = options.header();
+        assert!(!headers.contains_key(AMZ_OBJECT_LOCK_MODE));
+        assert!(!headers.contains_key(AMZ_OBJECT_LOCK_RETAIN_UNTIL_DATE));
+        assert_eq!(
+            rustfs_utils::http::get_header(&headers, SUFFIX_SOURCE_REPLICATION_RETENTION_TIMESTAMP).as_deref(),
+            Some("2026-01-02T03:04:05Z")
+        );
+    }
+
    #[test]
    fn replication_put_options_strip_encryption_metadata_from_plaintext_objects() {
        use rustfs_utils::http::object_encryption_keys::{INTERNAL_ENCRYPTION_ORIGINAL_SIZE_HEADER, SSEC_ORIGINAL_SIZE_HEADER};
@@ -40,7 +40,14 @@ impl ARN {

 impl Display for ARN {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "arn:rustfs:{}:{}:{}:{}", self.arn_type, self.region, self.id, self.bucket)
+        // The `minio` partition is deliberate: madmin-go's ParseARN
+        // hard-rejects any other partition, so native mc/madmin tooling can
+        // only decode remote-target ARNs minted in this form (backlog#1675
+        // P1-7). Legacy `arn:rustfs:` ARNs persisted by older releases stay
+        // readable via the FromStr whitelist below; runtime matching between
+        // targets and replication rules is by full-string equality, so mixed
+        // partitions coexist safely.
+        write!(f, "arn:minio:{}:{}:{}:{}", self.arn_type, self.region, self.id, self.bucket)
    }
 }

@@ -48,7 +55,12 @@ impl FromStr for ARN {
    type Err = std::io::Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        if !s.starts_with("arn:rustfs:") {
+        // Partition whitelist, not just an `arn:` check: `BucketTargetType::
+        // from_str(...).unwrap_or_default()` below never fails, so this is
+        // the only structural gate rejecting foreign ARNs. `arn:rustfs:` is
+        // the legacy partition and must stay accepted forever (persisted
+        // bucket-targets.json / replication configs from older releases).
+        if !s.starts_with("arn:minio:") && !s.starts_with("arn:rustfs:") {
            return Err(std::io::Error::new(std::io::ErrorKind::InvalidInput, "Invalid ARN format"));
        }

@@ -101,14 +113,50 @@ mod tests {
    }

    /// RustFS commonly generates ARNs with an empty region:
-    /// `arn:rustfs:replication::<deployment_id>:<bucket>`.
+    /// `arn:minio:replication::<deployment_id>:<bucket>`.
    #[test]
    fn from_str_handles_empty_region_segment() {
-        let parsed = ARN::from_str("arn:rustfs:replication::depl-123:bucket-a").expect("valid ARN must parse");
+        let parsed = ARN::from_str("arn:minio:replication::depl-123:bucket-a").expect("valid ARN must parse");

        assert_eq!(parsed.arn_type, BucketTargetType::ReplicationService);
        assert_eq!(parsed.region, "", "region segment is empty in this form");
        assert_eq!(parsed.id, "depl-123");
        assert_eq!(parsed.bucket, "bucket-a");
    }
+
+    /// madmin-go's `ParseARN` hard-rejects anything that does not start with
+    /// `arn:minio:`, so generated ARNs must use the `minio` partition or the
+    /// native mc/madmin tooling cannot decode remote-target listings.
+    #[test]
+    fn display_emits_minio_partition() {
+        let arn = ARN::new(
+            BucketTargetType::ReplicationService,
+            "depl-123".to_string(),
+            String::new(),
+            "bucket-a".to_string(),
+        );
+
+        assert_eq!(arn.to_string(), "arn:minio:replication::depl-123:bucket-a");
+    }
+
+    /// Persisted bucket-targets.json files from older RustFS releases carry
+    /// `arn:rustfs:` ARNs; the legacy partition must stay parseable forever.
+    #[test]
+    fn from_str_accepts_legacy_rustfs_partition() {
+        let parsed = ARN::from_str("arn:rustfs:replication:us-east-1:depl-123:bucket-a").expect("legacy ARN must parse");
+
+        assert_eq!(parsed.arn_type, BucketTargetType::ReplicationService);
+        assert_eq!(parsed.region, "us-east-1");
+        assert_eq!(parsed.id, "depl-123");
+        assert_eq!(parsed.bucket, "bucket-a");
+    }
+
+    /// The partition whitelist is the only structural gate: `BucketTargetType::
+    /// from_str(...).unwrap_or_default()` never fails, so any 6-segment string
+    /// would otherwise parse as `type=None`.
+    #[test]
+    fn from_str_rejects_unknown_partition() {
+        assert!(ARN::from_str("arn:aws:replication::depl-123:bucket-a").is_err());
+        assert!(ARN::from_str("not-an-arn").is_err());
+    }
 }
@@ -59,6 +59,10 @@ impl fmt::Debug for Credentials {
 }

 #[derive(Debug, Deserialize, Serialize, Default, Clone)]
+#[allow(
+    dead_code,
+    reason = "MinIO-parity bucket-target service discriminator with no caller in this port (backlog#1823)"
+)]
 pub enum ServiceType {
    #[default]
    Replication,
@@ -73,23 +73,6 @@ pub fn check_valid_bucket_name_strict(bucket_name: &str) -> Result<()> {
    check_bucket_name_common(bucket_name, true)
 }

-pub fn check_valid_object_name_prefix(object_name: &str) -> Result<()> {
-    if object_name.len() > 1024 {
-        return Err(Error::other("Object name cannot be longer than 1024 characters"));
-    }
-    if !object_name.is_ascii() {
-        return Err(Error::other("Object name with non-UTF-8 strings are not supported"));
-    }
-    Ok(())
-}
-
-pub fn check_valid_object_name(object_name: &str) -> Result<()> {
-    if object_name.trim().is_empty() {
-        return Err(Error::other("Object name cannot be empty"));
-    }
-    check_valid_object_name_prefix(object_name)
-}
-
 pub fn deserialize<T>(input: &[u8]) -> xml::DeResult<T>
 where
    T: for<'xml> xml::Deserialize<'xml>,
@@ -100,6 +83,10 @@ where
    Ok(ans)
 }

+#[allow(
+    dead_code,
+    reason = "xml serialize helper with no caller in this port; the live sibling is deserialize (backlog#1823)"
+)]
 pub fn serialize_content<T: xml::SerializeContent>(val: &T) -> xml::SerResult<String> {
    let mut buf = Vec::with_capacity(256);
    {
@@ -186,15 +173,27 @@ pub fn is_valid_object_name(object: &str) -> bool {
 /// Client-facing reason attached to rejections of object keys that Win32/NTFS
 /// cannot represent as file paths (issue #3299). Deployments on Linux/macOS
 /// accept the full S3 key character set.
+#[allow(
+    dead_code,
+    reason = "live on Windows: callers sit inside the #[cfg(target_os = \"windows\")] block in check_object_name_for_length_and_slash (backlog#1823)"
+)]
 pub const WINDOWS_RESERVED_CHARACTERS_REASON: &str =
    "object key contains characters unsupported on Windows hosts (one of ':', '*', '?', '\"', '|', '<', '>')";

 /// Client-facing reason for path segments Windows can store but not address
 /// afterwards (issue #3449): trailing dot/space or reserved DOS device names.
+#[allow(
+    dead_code,
+    reason = "live on Windows: callers sit inside the #[cfg(target_os = \"windows\")] block in check_object_name_for_length_and_slash (backlog#1823)"
+)]
 pub const WINDOWS_RESERVED_SEGMENT_REASON: &str = "object key contains a path segment unsupported on Windows hosts (trailing dot or space, or a reserved device name such as NUL/CON/COM1)";

 /// Reserved DOS device names that shadow regular files on Windows, even when
 /// an extension is appended (e.g. `NUL.txt` resolves to the `NUL` device).
+#[allow(
+    dead_code,
+    reason = "live on Windows: callers sit inside the #[cfg(target_os = \"windows\")] block in check_object_name_for_length_and_slash (backlog#1823)"
+)]
 const WINDOWS_RESERVED_NAMES: &[&str] = &[
    "CON", "PRN", "AUX", "NUL", "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9", "LPT1", "LPT2", "LPT3",
    "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9",
@@ -204,6 +203,10 @@ const WINDOWS_RESERVED_NAMES: &[&str] = &[
 /// the Win32 API cannot address afterwards (issue #3449): segments ending in a
 /// dot or a space, and reserved DOS device names — bare or with an extension
 /// (`NUL.txt`), matching classic Win32 path resolution semantics.
+#[allow(
+    dead_code,
+    reason = "live on Windows: callers sit inside the #[cfg(target_os = \"windows\")] block in check_object_name_for_length_and_slash (backlog#1823)"
+)]
 pub fn object_name_has_windows_incompatible_segment(object: &str) -> bool {
    object.split(['/', '\\']).any(|segment| {
        if segment.ends_with('.') || segment.ends_with(' ') {
@@ -90,6 +90,10 @@ impl BucketVersioningSys {
    /// caller's own instance context so a second in-process store never
    /// answers with the first instance's versioning state; falls back to the
    /// ambient system when the instance cell is not initialized.
+    #[allow(
+        dead_code,
+        reason = "instance-scoped seam (backlog#1052) with no caller in this port (backlog#1823)"
+    )]
    pub(crate) async fn get_in(ctx: &crate::runtime::instance::InstanceContext, bucket: &str) -> Result<VersioningConfiguration> {
        if bucket == RUSTFS_META_BUCKET || bucket.starts_with(RUSTFS_META_BUCKET) {
            return Ok(VersioningConfiguration::default());
@@ -15,6 +15,7 @@
 use crate::disk::disk_store::{get_drive_walkdir_peek_timeout, get_drive_walkdir_stall_timeout};
 use crate::disk::error::DiskError;
 use crate::disk::{self, DiskAPI, DiskStore, WalkDirOptions};
+use futures::future::join_all;
 use metrics::counter;
 use rustfs_filemeta::{MetaCacheEntries, MetaCacheEntry, MetacacheReader, is_io_eof};
 use std::{
@@ -655,6 +656,7 @@ async fn list_path_raw_inner(
            errs.push(None);
        }
        let mut pending_entries: Vec<Option<MetaCacheEntry>> = vec![None; readers.len()];
+        let mut peek_outcomes: Vec<Option<PeekOutcome>> = std::iter::repeat_with(|| None).take(readers.len()).collect();

        loop {
            let mut current = MetaCacheEntry::default();
@@ -676,6 +678,21 @@ async fn list_path_raw_inner(
            let mut has_err = 0;
            let mut agree = 0;

+            // Start every missing head read in the same round so one stalled
+            // disk cannot multiply the wait budget by the erasure-set width.
+            // Outcomes are still consumed below in stable disk-index order.
+            let concurrent_peeks = readers.iter_mut().enumerate().filter_map(|(i, reader)| {
+                if errs[i].is_some() || pending_entries[i].is_some() {
+                    return None;
+                }
+
+                let cancel = &revjob_rx;
+                Some(async move { (i, peek_with_timeout(cancel, reader, peek_timeout).await) })
+            });
+            for (i, outcome) in join_all(concurrent_peeks).await {
+                peek_outcomes[i] = Some(outcome);
+            }
+
            for (i, r) in readers.iter_mut().enumerate() {
                if errs[i].is_some() {
                    has_err += 1;
@@ -685,7 +702,10 @@ async fn list_path_raw_inner(
                let entry = if let Some(entry) = pending_entries[i].take() {
                    entry
                } else {
-                    match peek_with_timeout(&revjob_rx, r, peek_timeout).await {
+                    let Some(outcome) = peek_outcomes[i].take() else {
+                        return Err(DiskError::Unexpected);
+                    };
+                    match outcome {
                        PeekOutcome::Ready(res) => {
                            if let Some(entry) = res {
                                // info!("read entry disk: {}, name: {}", i, entry.name);
@@ -1295,6 +1315,36 @@ mod tests {
        assert_eq!(err, DiskError::Timeout);
    }

+    #[tokio::test(start_paused = true)]
+    async fn list_path_raw_bounds_multiple_stalled_readers_by_one_peek_deadline() {
+        let peek_timeout = Duration::from_millis(20);
+        let started = tokio::time::Instant::now();
+        let err = list_path_raw(
+            CancellationToken::new(),
+            ListPathRawOptions {
+                disks: vec![None, None, None, None],
+                min_disks: 1,
+                test_reader_behaviors: vec![
+                    TestReaderBehavior::Stall,
+                    TestReaderBehavior::Stall,
+                    TestReaderBehavior::Stall,
+                    TestReaderBehavior::Stall,
+                ],
+                peek_timeout: Some(peek_timeout),
+                ..Default::default()
+            },
+        )
+        .await
+        .expect_err("all stalled readers should fail the listing");
+
+        assert_eq!(err, DiskError::Timeout);
+        assert_eq!(
+            started.elapsed(),
+            peek_timeout,
+            "reader deadlines must overlap instead of accumulating once per disk"
+        );
+    }
+
    #[tokio::test]
    async fn list_path_raw_waits_past_producer_stall_for_slow_progressing_reader() {
        let entry = MetaCacheEntry {
@@ -229,17 +229,6 @@ pub fn http_resp_to_error_response(
    err_resp
 }

-pub fn err_transfer_acceleration_bucket(bucket_name: &str) -> ErrorResponse {
-    ErrorResponse {
-        status_code: StatusCode::BAD_REQUEST,
-        code: S3ErrorCode::InvalidArgument,
-        message: "The name of the bucket used for Transfer Acceleration must be DNS-compliant and must not contain periods ‘.’."
-            .to_string(),
-        bucket_name: bucket_name.to_string(),
-        ..Default::default()
-    }
-}
-
 pub fn err_entity_too_large(total_size: i64, max_object_size: i64, bucket_name: &str, object_name: &str) -> ErrorResponse {
    let msg = format!(
        "Your proposed upload size ‘{}’ exceeds the maximum allowed object size ‘{}’ for single PUT operation.",
@@ -295,16 +284,6 @@ pub fn err_invalid_argument(message: &str) -> ErrorResponse {
    }
 }

-pub fn err_api_not_supported(message: &str) -> ErrorResponse {
-    ErrorResponse {
-        status_code: StatusCode::NOT_IMPLEMENTED,
-        code: S3ErrorCode::Custom("APINotSupported".into()),
-        message: message.to_string(),
-        request_id: "rustfs".to_string(),
-        ..Default::default()
-    }
-}
-
 #[cfg(test)]
 mod tests {
    use super::*;
@@ -135,6 +135,10 @@ impl Object {
        Self { ..Default::default() }
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity reader surface with no caller in this port (backlog#1823)"
+    )]
    fn do_get_request(&self, request: &GetRequest) -> Result<GetResponse, std::io::Error> {
        let _ = request.did_offset_change;
        let _ = request.offset;
@@ -150,12 +154,20 @@ impl Object {
        ))
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity Object reader method with no caller in this port (backlog#1823)"
+    )]
    fn set_offset(&mut self, bytes_read: i64) -> Result<(), std::io::Error> {
        self.curr_offset += bytes_read;

        Ok(())
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity Object reader method with no caller in this port (backlog#1823)"
+    )]
    fn read(&mut self, b: &[u8]) -> Result<i64, std::io::Error> {
        let mut read_req = GetRequest {
            is_read_op: true,
@@ -180,6 +192,10 @@ impl Object {
        Ok(response.size)
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity Object reader method with no caller in this port (backlog#1823)"
+    )]
    fn stat(&self) -> Result<ObjectInfo, std::io::Error> {
        if !self.is_started || !self.object_info_set {
            let _ = self.do_get_request(&GetRequest {
@@ -192,6 +208,10 @@ impl Object {
        Ok(self.object_info.clone())
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity Object reader method with no caller in this port (backlog#1823)"
+    )]
    fn read_at(&mut self, b: &[u8], offset: i64) -> Result<i64, std::io::Error> {
        self.curr_offset = offset;

@@ -219,6 +239,10 @@ impl Object {
        Ok(response.size)
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity Object reader method with no caller in this port (backlog#1823)"
+    )]
    fn seek(&mut self, offset: i64, whence: i64) -> Result<i64, std::io::Error> {
        if !self.is_started || !self.object_info_set {
            let seek_req = GetRequest {
@@ -253,6 +277,10 @@ impl Object {
        Ok(self.curr_offset)
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity Object reader method with no caller in this port (backlog#1823)"
+    )]
    fn close(&mut self) -> Result<(), std::io::Error> {
        self.is_closed = true;
        Ok(())
@@ -37,7 +37,7 @@ use crate::client::{
    api_put_object_common::optimal_part_info,
    api_put_object_multipart::UploadPartParams,
    api_s3_datatypes::{CompleteMultipartUpload, CompletePart, ObjectPart},
-    constants::{ISO8601_DATEFORMAT, MAX_MULTIPART_PUT_OBJECT_SIZE, MIN_PART_SIZE, TOTAL_WORKERS},
+    constants::{ISO8601_DATEFORMAT, MAX_MULTIPART_PUT_OBJECT_SIZE, MIN_PART_SIZE},
    credentials::SignatureType,
    transition_api::{ReaderImpl, TransitionClient, UploadInfo},
    utils::{is_amz_header, is_minio_header, is_rustfs_header, is_standard_header, is_storageclass_header},
@@ -30,10 +30,6 @@ pub fn is_object(reader: &ReaderImpl) -> bool {
    matches!(reader, ReaderImpl::ObjectBody(_))
 }

-pub fn is_read_at(reader: ReaderImpl) -> bool {
-    matches!(reader, ReaderImpl::ObjectBody(_))
-}
-
 pub fn optimal_part_info(object_size: i64, configured_part_size: u64) -> Result<(i64, i64, i64), std::io::Error> {
    let unknown_size;
    let mut object_size = object_size;
@@ -81,18 +81,6 @@ async fn read_multipart_part(reader: &mut ReaderImpl, want: usize) -> Result<Vec
    }
 }

-pub struct UploadedPartRes {
-    pub error: std::io::Error,
-    pub part_num: i64,
-    pub size: i64,
-    pub part: ObjectPart,
-}
-
-pub struct UploadPartReq {
-    pub part_num: i64,
-    pub part: ObjectPart,
-}
-
 impl TransitionClient {
    pub async fn put_object_multipart_stream(
        self: Arc<Self>,
@@ -29,10 +29,6 @@ use crate::client::utils::base64_decode;

 use super::transition_api;

-pub struct ListAllMyBucketsResult {
-    pub owner: Owner,
-}
-
 #[derive(Debug, Default, Serialize, Deserialize)]
 pub struct CommonPrefix {
    pub prefix: String,
@@ -89,6 +85,10 @@ pub struct ListVersionsResult {
    pub next_version_id_marker: String,
 }

+#[allow(
+    dead_code,
+    reason = "fields of a MinIO-parity list result that this port builds but never reads back (backlog#1823)"
+)]
 pub struct ListBucketResult {
    common_prefixes: Vec<CommonPrefix>,
    contents: Vec<transition_api::ObjectInfo>,
@@ -102,6 +102,10 @@ pub struct ListBucketResult {
    prefix: String,
 }

+#[allow(
+    dead_code,
+    reason = "fields of a MinIO-parity list result that this port builds but never reads back (backlog#1823)"
+)]
 pub struct ListMultipartUploadsResult {
    bucket: String,
    key_marker: String,
@@ -117,16 +121,15 @@ pub struct ListMultipartUploadsResult {
    common_prefixes: Vec<CommonPrefix>,
 }

+#[allow(
+    dead_code,
+    reason = "fields of a MinIO-parity list result that this port builds but never reads back (backlog#1823)"
+)]
 pub struct Initiator {
    id: String,
    display_name: String,
 }

-pub struct CopyObjectResult {
-    pub etag: String,
-    pub last_modified: OffsetDateTime,
-}
-
 #[derive(Debug, Clone)]
 pub struct ObjectPart {
    pub etag: String,
@@ -260,6 +263,7 @@ pub struct CompletePart {
 }

 impl CompletePart {
+    #[allow(dead_code, reason = "MinIO-parity accessor with no caller in this port (backlog#1823)")]
    fn checksum(&self, t: &ChecksumMode) -> String {
        match t {
            ChecksumMode::ChecksumCRC32C => {
@@ -284,11 +288,6 @@ impl CompletePart {
    }
 }

-pub struct CopyObjectPartResult {
-    pub etag: String,
-    pub last_modified: OffsetDateTime,
-}
-
 #[derive(Debug, Default, serde::Serialize)]
 #[serde(rename = "CompleteMultipartUpload")]
 pub struct CompleteMultipartUpload {
@@ -357,10 +356,10 @@ impl CompleteMultipartUpload {
    }
 }

-pub struct CreateBucketConfiguration {
-    pub location: String,
-}
-
+#[allow(
+    dead_code,
+    reason = "live via quick_xml::de::from_str in bucket_cache.rs; serde deserialization is not a construction (backlog#1823)"
+)]
 #[derive(serde::Serialize)]
 pub struct DeleteObject {
    //api has
@@ -368,21 +367,6 @@ pub struct DeleteObject {
    pub version_id: String,
 }

-pub struct DeletedObject {
-    //s3s has
-    pub key: String,
-    pub version_id: String,
-    pub deletemarker: bool,
-    pub deletemarker_version_id: String,
-}
-
-pub struct NonDeletedObject {
-    pub key: String,
-    pub code: String,
-    pub message: String,
-    pub version_id: String,
-}
-
 #[derive(serde::Serialize)]
 pub struct DeleteMultiObjects {
    pub quiet: bool,
@@ -402,6 +386,7 @@ impl DeleteMultiObjects {
        Ok(buf)
    }

+    #[allow(dead_code, reason = "MinIO-parity XML helper with no caller in this port (backlog#1823)")]
    pub fn unmarshal(buf: &[u8]) -> Result<Self, std::io::Error> {
        #[derive(Debug, Deserialize)]
        struct WireDeleteObject {
@@ -436,8 +421,3 @@ impl DeleteMultiObjects {
        })
    }
 }
-
-pub struct DeleteMultiObjectsResult {
-    pub deleted_objects: Vec<DeletedObject>,
-    pub undeleted_objects: Vec<NonDeletedObject>,
-}
@@ -365,6 +365,10 @@ mod tests {
 pub struct Checksum {
    checksum_type: ChecksumMode,
    r: Vec<u8>,
+    #[allow(
+        dead_code,
+        reason = "checksum bookkeeping field kept beside the value it guards (backlog#1823)"
+    )]
    computed: bool,
 }

@@ -32,8 +32,5 @@ pub const MAX_MULTIPART_PUT_OBJECT_SIZE: i64 = 1024 * 1024 * 1024 * 1024 * 5;
 pub const UNSIGNED_PAYLOAD: &str = "UNSIGNED-PAYLOAD";
 pub const UNSIGNED_PAYLOAD_TRAILER: &str = "STREAMING-UNSIGNED-PAYLOAD-TRAILER";

-pub const TOTAL_WORKERS: i64 = 4;
-
-pub const SIGN_V4_ALGORITHM: &str = "AWS4-HMAC-SHA256";
 pub const ISO8601_DATEFORMAT: &[FormatItem<'_>] =
    format_description!("[year]-[month]-[day]T[hour]:[minute]:[second].[subsecond]Z");
@@ -67,6 +67,10 @@ impl<P: Provider + Default> Credentials<P> {
        Ok(self.creds.clone())
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity credential surface with no caller in this port (backlog#1823)"
+    )]
    fn expire(&mut self) {
        self.force_refresh = true;
    }
@@ -133,6 +137,10 @@ impl Provider for Static {

 #[derive(Debug, Clone, Default)]
 pub struct STSError {
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity STS error detail that this port never reads back (backlog#1823)"
+    )]
    pub r#type: String,
    pub code: String,
    pub message: String,
@@ -141,6 +149,10 @@ pub struct STSError {
 #[derive(Debug, Clone, thiserror::Error)]
 pub struct ErrorResponse {
    pub sts_error: STSError,
+    #[allow(
+        dead_code,
+        reason = "MinIO-parity STS error detail that this port never reads back (backlog#1823)"
+    )]
    pub request_id: String,
 }

@@ -158,22 +170,3 @@ impl ErrorResponse {
        return self.sts_error.message.clone();
    }
 }
-
-pub fn xml_decoder<T>(body: &[u8]) -> Result<T, Error>
-where
-    for<'de> T: Deserialize<'de>,
-{
-    match std::str::from_utf8(body) {
-        Ok(xml_body) => quick_xml::de::from_str::<T>(xml_body).map_err(|err| Error::new(ErrorKind::InvalidData, err.to_string())),
-        Err(err) => Err(Error::new(ErrorKind::InvalidData, err.to_string())),
-    }
-}
-
-pub fn xml_decode_and_body<T>(body_reader: &[u8]) -> Result<(Vec<u8>, T), std::io::Error>
-where
-    for<'de> T: Deserialize<'de>,
-{
-    let body = body_reader.to_vec();
-    let parsed = xml_decoder(&body)?;
-    Ok((body, parsed))
-}
@@ -13,7 +13,6 @@
 // limitations under the License.

 // #730: S3 client compatibility models are kept while ECStore callers move to narrower facades.
-#![allow(dead_code)]

 pub mod admin_handler_utils;
 pub mod api_error_response;
@@ -77,39 +77,6 @@ fn part_number_to_rangespec(oi: ObjectInfo, part_number: usize) -> Option<HTTPRa
    })
 }

-fn get_compressed_offsets(oi: ObjectInfo, offset: i64) -> (i64, i64, i64, i64, u64) {
-    let mut skip_length: i64 = 0;
-    let mut cumulative_actual_size: i64 = 0;
-    let mut first_part_idx: i64 = 0;
-    let mut compressed_offset: i64 = 0;
-    let mut part_skip: i64 = 0;
-    let mut decrypt_skip: i64 = 0;
-    let mut seq_num: u64 = 0;
-    for (i, part) in oi.parts.iter().enumerate() {
-        cumulative_actual_size += part.actual_size as i64;
-        if cumulative_actual_size <= offset {
-            compressed_offset += part.size as i64;
-        } else {
-            first_part_idx = i as i64;
-            skip_length = cumulative_actual_size - part.actual_size as i64;
-            break;
-        }
-    }
-    skip_length = offset - skip_length;
-
-    let parts: &[ObjectPartInfo] = &oi.parts;
-    if skip_length > 0
-        && parts.len() > first_part_idx as usize
-        && parts[first_part_idx as usize].index.as_ref().is_some_and(|idx| idx.len() > 0)
-    {
-        let _ = part_skip;
-        let _ = decrypt_skip;
-        let _ = seq_num;
-    }
-
-    (compressed_offset, part_skip, first_part_idx, decrypt_skip, seq_num)
-}
-
 pub fn new_getobjectreader<'a>(
    rs: &Option<HTTPRangeSpec>,
    oi: &'a ObjectInfo,
@@ -23,6 +23,7 @@ const X_OBS_VERSION_ID: &str = "x-obs-version-id";
 const MAX_REMOTE_VERSION_ID_LEN: usize = 1024;

 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[allow(dead_code, reason = "bucket versioning states kept as a complete vocabulary (backlog#1823)")]
 pub(crate) enum BucketVersioningState {
    Unknown,
    Disabled,
@@ -47,6 +48,7 @@ impl RemoteVersion {
        }
    }

+    #[allow(dead_code, reason = "MinIO-parity accessor with no caller in this port (backlog#1823)")]
    pub(crate) fn exact_request_id(&self) -> Result<Option<&str>, Error> {
        match self {
            Self::Unknown => Err(Error::new(
@@ -101,6 +101,10 @@ where

 const C_UNKNOWN: i32 = -1;
 const C_OFFLINE: i32 = 0;
+#[allow(
+    dead_code,
+    reason = "reachable only from the unused transition client methods below (backlog#1823)"
+)]
 const C_ONLINE: i32 = 1;

 fn invalid_utf8_header_error(scope: &str, header_name: &str) -> std::io::Error {
@@ -320,6 +324,10 @@ impl TransitionClient {
        Ok(client)
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity transition client surface with no caller in this port (backlog#1823)"
+    )]
    fn endpoint_url(&self) -> Url {
        self.endpoint_url.clone()
    }
@@ -348,12 +356,20 @@ impl TransitionClient {
            .to_string())
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity transition client method with no caller in this port (backlog#1823)"
+    )]
    fn trace_errors_only_off(&self) {
        if let Ok(mut trace_errors_only) = self.trace_errors_only.lock() {
            *trace_errors_only = false;
        }
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity transition client method with no caller in this port (backlog#1823)"
+    )]
    fn trace_off(&self) {
        if let Ok(mut is_trace_enabled) = self.is_trace_enabled.lock() {
            *is_trace_enabled = false;
@@ -363,12 +379,20 @@ impl TransitionClient {
        }
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity transition client method with no caller in this port (backlog#1823)"
+    )]
    fn set_s3_transfer_accelerate(&self, accelerate_endpoint: &str) {
        if let Ok(mut endpoint) = self.s3_accelerate_endpoint.lock() {
            *endpoint = accelerate_endpoint.to_string();
        }
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity transition client method with no caller in this port (backlog#1823)"
+    )]
    fn set_s3_enable_dual_stack(&self, enabled: bool) {
        if let Ok(mut dual_stack) = self.s3_dual_stack_enabled.lock() {
            *dual_stack = enabled;
@@ -398,10 +422,18 @@ impl TransitionClient {
        (hash_algos, hash_sums)
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity transition client method with no caller in this port (backlog#1823)"
+    )]
    fn is_online(&self) -> bool {
        !self.is_offline()
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity transition client method with no caller in this port (backlog#1823)"
+    )]
    fn mark_offline(&self) {
        self.health_status
            .compare_exchange(C_ONLINE, C_OFFLINE, Ordering::SeqCst, Ordering::SeqCst);
@@ -411,10 +443,18 @@ impl TransitionClient {
        self.health_status.load(Ordering::SeqCst) == C_OFFLINE
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity transition client method with no caller in this port (backlog#1823)"
+    )]
    fn health_check(hc_duration: Duration) {
        let _ = hc_duration;
    }

+    #[allow(
+        dead_code,
+        reason = "MinIO-parity transition client method with no caller in this port (backlog#1823)"
+    )]
    fn dump_http(&self, req: &Request<s3s::Body>, resp: &Response<Incoming>) -> Result<(), std::io::Error> {
        let mut resp_trace: Vec<u8>;

@@ -1102,6 +1142,7 @@ impl Default for ObjectInfo {
 }

 impl ObjectInfo {
+    #[allow(dead_code, reason = "MinIO-parity accessor with no caller in this port (backlog#1823)")]
    pub(crate) fn remote_version(
        &self,
        capabilities: ProviderVersionCapabilities,
@@ -48,10 +48,6 @@ lazy_static! {
    };
 }

-pub fn is_standard_query_value(qs_key: &str) -> bool {
-    SUPPORTED_QUERY_VALUES[qs_key]
-}
-
 pub fn is_storageclass_header(header_key: &str) -> bool {
    header_key.to_lowercase() == X_AMZ_STORAGE_CLASS.as_str().to_lowercase()
 }
@@ -13,7 +13,6 @@
 // limitations under the License.

 // #730: cluster/RPC migration leaves transport capabilities staged for upcoming owners.
-#![allow(dead_code)]

 mod control_plane;
 pub(crate) mod rpc;
@@ -256,6 +256,7 @@ impl<S> ReplayScopeChannel<S> {
    }
 }

+#[allow(dead_code, reason = "replay-state probe asserted by this file's tests (backlog#1823)")]
 fn peer_replay_state(audience: &str) -> PeerReplayState {
    PEER_REPLAY_STATES
        .lock()
@@ -43,6 +43,10 @@ use tokio::io::{AsyncReadExt, AsyncWrite};
 use tokio::sync::OnceCell;
 use uuid::Uuid;

+#[allow(
+    dead_code,
+    reason = "live in the cfg(not(test)) half of build_internode_data_transport_from_env (backlog#1823)"
+)]
 static INTERNODE_DATA_TRANSPORT: OnceLock<std::result::Result<Arc<dyn InternodeDataTransport>, String>> = OnceLock::new();

 const READ_FILE_STREAM_PATH: &str = "/rustfs/rpc/read_file_stream";
@@ -134,6 +138,10 @@ fn put_file_capability_status_is_legacy(status: u16) -> bool {
 }

 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
+#[allow(
+    dead_code,
+    reason = "capability-negotiation seam; constructed only by transport test doubles (backlog#1823)"
+)]
 pub struct InternodeDataTransportCapabilities {
    /// Backend can open a streaming remote disk reader.
    pub streaming_read: bool,
@@ -150,6 +158,10 @@ pub struct InternodeDataTransportCapabilities {
 }

 impl InternodeDataTransportCapabilities {
+    #[allow(
+        dead_code,
+        reason = "capability-negotiation seam; used by transport test doubles (backlog#1823)"
+    )]
    pub const fn tcp_http() -> Self {
        Self {
            streaming_read: true,
@@ -234,7 +246,12 @@ pub trait InternodeDataTransport: Send + Sync + std::fmt::Debug {
    async fn probe_ns_scanner(&self, _request: NsScannerCapabilityRequest) -> Result<Uuid> {
        Err(Error::MethodNotAllowed)
    }
+    // Interface facet nobody calls yet: every transport implements both, but no
+    // caller negotiates on them. Kept for the internode transport split
+    // (backlog#1350); deleting them would delete the seam and six impls.
+    #[allow(dead_code, reason = "unused capability-negotiation facet (backlog#1823)")]
    fn name(&self) -> &'static str;
+    #[allow(dead_code, reason = "unused capability-negotiation facet (backlog#1823)")]
    fn capabilities(&self) -> InternodeDataTransportCapabilities;
 }

@@ -670,6 +687,10 @@ fn build_internode_data_transport_result(
    }
 }

+#[allow(
+    dead_code,
+    reason = "live in the cfg(test) half of build_internode_data_transport_from_env, which bypasses the process static (backlog#1823)"
+)]
 pub fn build_internode_data_transport(configured_transport: Option<&str>) -> Result<Arc<dyn InternodeDataTransport>> {
    build_internode_data_transport_result(configured_transport).map_err(Error::other)
 }
@@ -248,6 +248,16 @@ fn decode_remote_version_state_capability(expected_member: &str, result: &[u8])
    Ok(server_epoch)
 }

+fn decode_cross_pool_fence_capability(expected_member: &str, result: &[u8]) -> Result<(u32, Uuid)> {
+    let version = result
+        .get(..4)
+        .and_then(|value| value.try_into().ok())
+        .map(u32::from_be_bytes)
+        .ok_or_else(|| Error::other("peer returned an invalid cross-pool fence capability version"))?;
+    let epoch = decode_remote_version_state_capability(expected_member, &result[4..])?;
+    Ok((version, epoch))
+}
+
 #[derive(Clone, Debug)]
 pub struct PeerLiveEventsBatch {
    pub events: Vec<u8>,
@@ -1288,6 +1298,16 @@ impl PeerRestClient {
        Ok((self.topology_member.clone(), epoch))
    }

+    pub async fn probe_cross_pool_fence(&self, topology_fingerprint: String) -> Result<(String, u32, Uuid)> {
+        let mut probe = rustfs_protos::CROSS_POOL_FENCE_CAPABILITY_PROBE_PREFIX.to_vec();
+        probe.extend_from_slice(Uuid::new_v4().as_bytes());
+        let result = self
+            .heal_control(rustfs_protos::HEAL_CONTROL_PROTOCOL_VERSION, topology_fingerprint, probe)
+            .await?;
+        let (supported_version, epoch) = decode_cross_pool_fence_capability(&self.topology_member, &result)?;
+        Ok((self.topology_member.clone(), supported_version, epoch))
+    }
+
    pub async fn load_bucket_metadata(&self, bucket: &str, scanner_maintenance_change: bool) -> Result<()> {
        self.finalize_result(
            async {
@@ -2738,6 +2758,24 @@ mod tests {
        assert!(decode_remote_version_state_capability("node-a:9000", &nil).is_err());
    }

+    #[test]
+    fn cross_pool_fence_capability_decoder_fails_closed() {
+        let epoch = Uuid::new_v4();
+        let result = rustfs_protos::encode_cross_pool_fence_capability(1, "node-a:9000", epoch.as_bytes())
+            .expect("small capability response should encode");
+        assert_eq!(
+            decode_cross_pool_fence_capability("node-a:9000", &result).expect("valid capability should decode"),
+            (1, epoch)
+        );
+        for malformed in [&[][..], &[0, 0, 0][..], &result[..result.len() - 1]] {
+            assert!(decode_cross_pool_fence_capability("node-a:9000", malformed).is_err());
+        }
+        assert!(decode_cross_pool_fence_capability("node-b:9000", &result).is_err());
+        let nil = rustfs_protos::encode_cross_pool_fence_capability(1, "node-a:9000", Uuid::nil().as_bytes())
+            .expect("small capability response should encode");
+        assert!(decode_cross_pool_fence_capability("node-a:9000", &nil).is_err());
+    }
+
    struct TierMutationResponseFixture<'a> {
        version: u32,
        phase: TierMutationRpcPhase,
@@ -854,7 +854,6 @@ impl PeerS3Client for LocalPeerS3Client {

 #[derive(Debug)]
 pub struct RemotePeerS3Client {
-    pub node: Option<Node>,
    pub pools: Option<Vec<usize>>,
    addr: String,
    /// Health tracker for connection monitoring
@@ -886,7 +885,6 @@ impl RemotePeerS3Client {
    pub fn new(node: Option<Node>, pools: Option<Vec<usize>>) -> Self {
        let addr = node.as_ref().map(|v| v.url.to_string()).unwrap_or_default();
        let client = Self {
-            node,
            pools,
            addr,
            health: Arc::new(DiskHealthTracker::new()),
@@ -905,10 +903,6 @@ impl RemotePeerS3Client {
            .map_err(|err| Error::other(format!("can not get client, err: {err}")))
    }

-    pub fn get_addr(&self) -> String {
-        self.addr.clone()
-    }
-
    /// Start health monitoring for the remote peer
    fn start_health_monitoring(&self) {
        let health = Arc::clone(&self.health);
@@ -1208,6 +1202,10 @@ impl PeerS3Client for RemotePeerS3Client {
    }
 }

+#[allow(
+    dead_code,
+    reason = "local bucket-heal path reached only by this file's tests (backlog#1823)"
+)]
 pub async fn heal_bucket_local(bucket: &str, opts: &HealOpts) -> Result<HealResultItem> {
    let disks = clone_drives().await;
    heal_bucket_local_on_disks(bucket, opts, disks).await
@@ -1404,6 +1402,10 @@ pub(crate) async fn heal_bucket_local_on_disks(
    }
 }

+#[allow(
+    dead_code,
+    reason = "reached only through heal_bucket_local, which only tests call (backlog#1823)"
+)]
 async fn clone_drives() -> Vec<Option<DiskStore>> {
    runtime_sources::local_disk_entries().await
 }
@@ -1585,15 +1587,7 @@ mod tests {
    }

    fn test_remote_peer(addr: &str) -> RemotePeerS3Client {
-        let node = Node {
-            url: url::Url::parse(addr).expect("test peer URL should parse"),
-            pools: vec![0],
-            is_local: false,
-            grid_host: addr.to_string(),
-        };
-
        RemotePeerS3Client {
-            node: Some(node),
            pools: Some(vec![0]),
            addr: addr.to_string(),
            health: Arc::new(DiskHealthTracker::new()),
@@ -1359,6 +1359,71 @@ fn validate_decoded_file_info(file_info: &FileInfo) -> Result<()> {
    file_info.validate_for_metadata_read().map_err(Into::into)
 }

+impl RemoteDisk {
+    #[tracing::instrument(level = "trace", skip_all)]
+    pub(crate) async fn rename_data_borrowed(
+        &self,
+        src_volume: &str,
+        src_path: &str,
+        fi: &FileInfo,
+        dst_volume: &str,
+        dst_path: &str,
+    ) -> Result<RenameDataResp> {
+        trace!(
+            event = EVENT_REMOTE_DISK_RPC,
+            component = LOG_COMPONENT_ECSTORE,
+            subsystem = LOG_SUBSYSTEM_REMOTE_DISK,
+            endpoint = %self.endpoint,
+            src_volume,
+            src_path,
+            dst_volume,
+            dst_path,
+            op = "rename_data",
+            state = "started",
+            "Remote disk RPC started"
+        );
+
+        self.execute_with_timeout_for_op(
+            "rename_data",
+            || async {
+                let file_info = compat_json(fi)?;
+                let file_info_bin = encode_file_info_msgpack(fi)?;
+                let mut client = self
+                    .get_client()
+                    .await
+                    .map_err(|err| Error::other(format!("can not get client, err: {err}")))?;
+                let mut request = Request::new(RenameDataRequest {
+                    disk: self.endpoint.to_string(),
+                    src_volume: src_volume.to_string(),
+                    src_path: src_path.to_string(),
+                    file_info,
+                    dst_volume: dst_volume.to_string(),
+                    dst_path: dst_path.to_string(),
+                    file_info_bin: file_info_bin.into(),
+                });
+                let canonical_body = rustfs_protos::canonical_rename_data_request_body(request.get_ref());
+                attach_mutation_body_digest(&mut request, canonical_body, "rename_data")?;
+
+                let response = client.rename_data(request).await?.into_inner();
+
+                if !response.success {
+                    return Err(response.error.unwrap_or_default().into());
+                }
+
+                let rename_data_resp = decode_msgpack_or_json::<RenameDataResp>(
+                    &response.rename_data_resp_bin,
+                    &response.rename_data_resp,
+                    "RenameDataResp",
+                )?;
+
+                Ok(rename_data_resp)
+            },
+            get_max_timeout_duration(),
+        )
+        .await
+    }
+}
+
 #[async_trait::async_trait]
 impl DiskAPI for RemoteDisk {
    #[tracing::instrument(level = "trace", skip_all)]
@@ -2284,58 +2349,8 @@ impl DiskAPI for RemoteDisk {
        dst_volume: &str,
        dst_path: &str,
    ) -> Result<RenameDataResp> {
-        trace!(
-            event = EVENT_REMOTE_DISK_RPC,
-            component = LOG_COMPONENT_ECSTORE,
-            subsystem = LOG_SUBSYSTEM_REMOTE_DISK,
-            endpoint = %self.endpoint,
-            src_volume,
-            src_path,
-            dst_volume,
-            dst_path,
-            op = "rename_data",
-            state = "started",
-            "Remote disk RPC started"
-        );
-
-        self.execute_with_timeout_for_op(
-            "rename_data",
-            || async {
-                let file_info = compat_json(&fi)?;
-                let file_info_bin = encode_file_info_msgpack(&fi)?;
-                let mut client = self
-                    .get_client()
-                    .await
-                    .map_err(|err| Error::other(format!("can not get client, err: {err}")))?;
-                let mut request = Request::new(RenameDataRequest {
-                    disk: self.endpoint.to_string(),
-                    src_volume: src_volume.to_string(),
-                    src_path: src_path.to_string(),
-                    file_info,
-                    dst_volume: dst_volume.to_string(),
-                    dst_path: dst_path.to_string(),
-                    file_info_bin: file_info_bin.into(),
-                });
-                let canonical_body = rustfs_protos::canonical_rename_data_request_body(request.get_ref());
-                attach_mutation_body_digest(&mut request, canonical_body, "rename_data")?;
-
-                let response = client.rename_data(request).await?.into_inner();
-
-                if !response.success {
-                    return Err(response.error.unwrap_or_default().into());
-                }
-
-                let rename_data_resp = decode_msgpack_or_json::<RenameDataResp>(
-                    &response.rename_data_resp_bin,
-                    &response.rename_data_resp,
-                    "RenameDataResp",
-                )?;
-
-                Ok(rename_data_resp)
-            },
-            get_max_timeout_duration(),
-        )
-        .await
+        self.rename_data_borrowed(src_volume, src_path, &fi, dst_volume, dst_path)
+            .await
    }

    #[tracing::instrument(level = "trace", skip_all)]
@@ -48,10 +48,6 @@ impl RemoteClient {
        Self { addr: endpoint }
    }

-    pub fn from_url(url: url::Url) -> Self {
-        Self { addr: url.to_string() }
-    }
-
    fn build_ping_request() -> PingRequest {
        let mut fbb = flatbuffers::FlatBufferBuilder::new();
        let payload = fbb.create_vector(b"health-check");
@@ -46,7 +46,6 @@ use rustfs_config::{
    SCANNER_SUB_SYS,
 };
 use rustfs_filemeta::FileInfo;
-use rustfs_utils::path::SLASH_SEPARATOR;
 use serde_json::{Map, Value};
 use std::collections::{HashMap, HashSet};
 use std::sync::LazyLock;
@@ -200,8 +199,6 @@ pub const STORAGE_CLASS_SUB_SYS: &str = "storage_class";

 pub const COMMA_SEPARATED_LISTS: &[&str] = &[rustfs_config::oidc::OIDC_SCOPES, rustfs_config::oidc::OIDC_OTHER_AUDIENCES];

-static CONFIG_BUCKET: LazyLock<String> = LazyLock::new(|| format!("{RUSTFS_META_BUCKET}{SLASH_SEPARATOR}{CONFIG_PREFIX}"));
-
 type ServerConfigDecryptFn = crate::bucket::migration::LegacyBlobDecryptFn;

 static SERVER_CONFIG_DECRYPT_FN: LazyLock<RwLock<Option<ServerConfigDecryptFn>>> = LazyLock::new(|| RwLock::new(None));
@@ -13,7 +13,6 @@
 // limitations under the License.

 // #730: configuration migration keeps legacy subsystem definitions available behind this module.
-#![allow(dead_code)]

 mod audit;
 pub mod com;
@@ -101,6 +101,7 @@ const DEFAULT_RRS_STORAGE_CLASS: &str = "EC:1";
 const ZERO_SET_DRIVE_COUNT_ERROR: &str = "set drive count must be greater than zero";

 pub static DEFAULT_INLINE_BLOCK: usize = 128 * 1024;
+const DEFAULT_INLINE_OBJECT_BUDGET: usize = 2 * DEFAULT_INLINE_BLOCK;

 pub static DEFAULT_KVS: LazyLock<KVS> = LazyLock::new(|| {
    let kvs = vec![
@@ -150,6 +151,8 @@ pub struct Config {
    optimize: Option<String>,
    inline_block: usize,
    initialized: bool,
+    #[serde(default, skip_serializing_if = "std::ops::Not::not")]
+    inline_block_explicit: bool,
    #[serde(skip)]
    standard_parities: Vec<PoolParity>,
    #[serde(skip)]
@@ -186,6 +189,10 @@ impl Config {
    /// A topology-bound lookup fails closed for unknown drive counts and for
    /// deserialized legacy configurations that have no pool topology. Legacy
    /// callers retain scalar compatibility through [`Self::get_parity_for_sc`].
+    #[allow(
+        dead_code,
+        reason = "per-set parity resolution asserted by this file's tests (backlog#1823)"
+    )]
    pub(crate) fn parity_for_sc(&self, sc: &str, drives_per_set: usize) -> Option<usize> {
        if !self.initialized {
            return None;
@@ -233,17 +240,19 @@ impl Config {
            .map(|(pool_index, pool)| (pool_index, pool.drives_per_set))
    }

-    pub fn should_inline(&self, shard_size: i64, versioned: bool) -> bool {
-        if shard_size < 0 {
+    pub fn should_inline(&self, shard_size: i64, data_shards: usize, versioned: bool) -> bool {
+        if shard_size < 0 || data_shards == 0 {
            return false;
        }

        let shard_size = shard_size as usize;
-
-        let mut inline_block = DEFAULT_INLINE_BLOCK;
-        if self.initialized {
-            inline_block = self.inline_block;
-        }
+        // Keep the historical two-data-shard object budget while preventing
+        // wider EC layouts from multiplying the maximum inline object size.
+        let inline_block = if self.initialized && self.inline_block_explicit {
+            self.inline_block
+        } else {
+            (DEFAULT_INLINE_OBJECT_BUDGET / data_shards).min(DEFAULT_INLINE_BLOCK)
+        };

        if versioned {
            shard_size <= inline_block / 8
@@ -392,6 +401,7 @@ fn lookup_config_for_pools_with_env(
    }

    let optimize = overrides.optimize;
+    let inline_block_explicit = overrides.inline_block.is_some();
    let inline_block = if let Some(value) = overrides.inline_block {
        let block = value
            .parse::<bytesize::ByteSize>()
@@ -424,6 +434,7 @@ fn lookup_config_for_pools_with_env(
        optimize,
        inline_block,
        initialized: true,
+        inline_block_explicit,
        standard_parities,
        rrs_parities,
    })
@@ -541,22 +552,26 @@ mod tests {
    }

    #[test]
-    fn should_inline_preserves_exact_default_shard_boundaries() {
-        let config = Config::default();
+    fn should_inline_scales_default_threshold_by_data_shards() {
+        let config = lookup_config_for_pools_with_env(&KVS::new(), &[3, 12], no_env_overrides())
+            .expect("default inline policy should resolve for EC2+1 and EC8+4");

-        for (case, shard_size, versioned, expected) in [
-            ("unversioned below", 128 * 1024 - 1, false, true),
-            ("unversioned exact", 128 * 1024, false, true),
-            ("unversioned above", 128 * 1024 + 1, false, false),
-            ("versioned below", 16 * 1024 - 1, true, true),
-            ("versioned exact", 16 * 1024, true, true),
-            ("versioned above", 16 * 1024 + 1, true, false),
-            ("negative", -1, false, false),
+        for (case, shard_size, data_shards, versioned, expected) in [
+            ("EC2+1 unversioned exact", 128 * 1024, 2, false, true),
+            ("EC2+1 unversioned above", 128 * 1024 + 1, 2, false, false),
+            ("EC2+1 versioned exact", 16 * 1024, 2, true, true),
+            ("EC2+1 versioned above", 16 * 1024 + 1, 2, true, false),
+            ("EC8+4 unversioned exact", 32 * 1024, 8, false, true),
+            ("EC8+4 unversioned above", 32 * 1024 + 1, 8, false, false),
+            ("EC8+4 versioned exact", 4 * 1024, 8, true, true),
+            ("EC8+4 versioned above", 4 * 1024 + 1, 8, true, false),
+            ("negative", -1, 2, false, false),
+            ("zero data shards", 0, 0, false, false),
        ] {
            assert_eq!(
-                config.should_inline(shard_size, versioned),
+                config.should_inline(shard_size, data_shards, versioned),
                expected,
-                "{case}: shard_size={shard_size}, versioned={versioned}"
+                "{case}: shard_size={shard_size}, data_shards={data_shards}, versioned={versioned}"
            );
        }
    }
@@ -577,13 +592,28 @@ mod tests {
            let shard_size = erasure.shard_file_size(object_size);
            assert_eq!(shard_size, expected_shard_size, "{case}: object_size={object_size}");
            assert_eq!(
-                config.should_inline(shard_size, versioned),
+                config.should_inline(shard_size, erasure.data_shards, versioned),
                expected,
                "{case}: object_size={object_size}, shard_size={shard_size}, versioned={versioned}"
            );
        }
    }

+    #[test]
+    fn explicit_inline_block_preserves_fixed_per_shard_rollback() {
+        let overrides = StorageClassEnvOverrides {
+            inline_block: Some("128KiB".to_string()),
+            ..Default::default()
+        };
+        let config = lookup_config_for_pools_with_env(&KVS::new(), &[12], overrides)
+            .expect("explicit inline block should resolve for EC8+4");
+
+        assert!(config.should_inline(128 * 1024, 8, false));
+        assert!(!config.should_inline(128 * 1024 + 1, 8, false));
+        assert!(config.should_inline(16 * 1024, 8, true));
+        assert!(!config.should_inline(16 * 1024 + 1, 8, true));
+    }
+
    #[test]
    fn write_capability_contract_only_accepts_implemented_layouts() {
        assert_eq!(SUPPORTED_WRITE_CLASSES, [STANDARD, RRS]);
@@ -777,6 +807,7 @@ mod tests {
        let encoded = serde_json::to_string(&cfg).expect("config should serialize");
        assert!(!encoded.contains("standard_parities"));
        assert!(!encoded.contains("rrs_parities"));
+        assert!(!encoded.contains("inline_block_explicit"));

        let decoded: Config = serde_json::from_str(&encoded).expect("legacy scalar config should deserialize");
        assert_eq!(decoded.get_parity_for_sc(STANDARD), Some(2));
@@ -786,6 +817,25 @@ mod tests {
        assert!(validate_parity(0, 0).is_err());
    }

+    #[test]
+    fn explicit_inline_block_survives_config_round_trip() {
+        let cfg = lookup_config_for_pools_with_env(
+            &KVS::new(),
+            &[12],
+            StorageClassEnvOverrides {
+                inline_block: Some("128KiB".to_string()),
+                ..Default::default()
+            },
+        )
+        .expect("explicit inline block should resolve");
+        assert!(cfg.should_inline(100 * 1024, 8, false));
+
+        let encoded = serde_json::to_string(&cfg).expect("config should serialize");
+        assert!(encoded.contains("\"inline_block_explicit\":true"));
+        let decoded: Config = serde_json::from_str(&encoded).expect("explicit inline config should deserialize");
+        assert!(decoded.should_inline(100 * 1024, 8, false));
+    }
+
    #[test]
    fn lookup_config_reads_rrs_from_class_rrs_key() {
        // Regression: kvs.get(RRS) used RRS="REDUCED_REDUNDANCY" instead of
@@ -13,7 +13,6 @@
 // limitations under the License.

 // #730: pool coordination helpers are being migrated behind runtime owners.
-#![allow(dead_code)]

 pub(crate) mod pools;
 pub(crate) mod sets;
@@ -226,6 +226,7 @@ fn ensure_decommission_start_rebalance_meta_allowed(meta: Option<&RebalanceMeta>
    ensure_decommission_not_rebalancing(meta.is_some_and(is_rebalance_conflicting_with_decommission))
 }

+#[allow(dead_code, reason = "leader precondition asserted by this file's tests (backlog#1823)")]
 fn ensure_local_decommission_pool_leaders(endpoints: &EndpointServerPools, indices: &[usize]) -> Result<()> {
    for idx in indices {
        ensure_local_decommission_pool_leader(endpoints, *idx)?;
@@ -1058,11 +1059,19 @@ fn should_cleanup_decommission_source_entry(decommissioned: usize, total_version
 }

 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[allow(
+    dead_code,
+    reason = "terminal-state classification asserted by this file's tests (backlog#1823)"
+)]
 enum DecommissionTerminalState {
    Completed,
    Failed,
 }

+#[allow(
+    dead_code,
+    reason = "terminal-state classification asserted by this file's tests (backlog#1823)"
+)]
 fn classify_decommission_terminal_state(failed_items_present: bool) -> DecommissionTerminalState {
    if failed_items_present {
        DecommissionTerminalState::Failed
@@ -13,7 +13,6 @@
 // limitations under the License.

 // #730: data-movement migration keeps staged cleanup helpers until copy paths converge.
-#![allow(dead_code)]

 pub(crate) mod backpressure;

@@ -1019,6 +1018,10 @@ struct SourceCleanupDeleteBarrierState {
 }

 #[cfg(test)]
+#[allow(
+    dead_code,
+    reason = "installed by set_disk object tests behind `--features test-util` (backlog#1823)"
+)]
 pub(crate) struct SourceCleanupDeleteBarrier {
    state: Arc<SourceCleanupDeleteBarrierState>,
 }
@@ -1028,6 +1031,10 @@ static SOURCE_CLEANUP_DELETE_BARRIER: std::sync::OnceLock<std::sync::Mutex<Optio
    std::sync::OnceLock::new();

 #[cfg(test)]
+#[allow(
+    dead_code,
+    reason = "installed by set_disk object tests behind `--features test-util` (backlog#1823)"
+)]
 impl SourceCleanupDeleteBarrier {
    pub(crate) fn install(bucket: &str, object: &str) -> Self {
        let state = Arc::new(SourceCleanupDeleteBarrierState {
@@ -1166,6 +1173,7 @@ async fn find_data_movement_target_info(
    }
 }

+#[allow(dead_code, reason = "resume adjudication asserted by this file's tests (backlog#1823)")]
 fn resolve_data_movement_overwrite_resume_result(
    err: &Error,
    target_result: Result<Option<ObjectInfo>>,
@@ -12,6 +12,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

+//! Per-disk usage snapshots persisted under the metadata bucket.
+//!
+//! **Nothing calls into this module.** It landed complete with tests in #5307
+//! (2026-07-27) and its aggregation entry point,
+//! [`crate::data_usage::aggregate_local_snapshots`], has never had a caller in
+//! the tree's history. The live data-usage path is
+//! `load_data_usage_from_backend` / `store_data_usage_in_backend`. The items
+//! below therefore carry individual `dead_code` allows rather than a module
+//! blanket, so the gap stays greppable until it is either wired up or removed.
+
 use crate::data_usage::BucketUsageInfo;
 use crate::disk::RUSTFS_META_BUCKET;
 use crate::error::{Error, Result};
@@ -26,10 +36,12 @@ pub const DATA_USAGE_DIR: &str = "datausage";
 /// Directory used to store incremental scan state files under the metadata bucket.
 pub const DATA_USAGE_STATE_DIR: &str = "datausage/state";
 /// Snapshot file format version, allows forward compatibility if the structure evolves.
+#[allow(dead_code, reason = "unwired local usage-snapshot feature; see module docs (backlog#1823)")]
 pub const LOCAL_USAGE_SNAPSHOT_VERSION: u32 = 1;

 /// Additional metadata describing which disk produced the snapshot.
 #[derive(Debug, Clone, Serialize, Deserialize, Default)]
+#[allow(dead_code, reason = "unwired local usage-snapshot feature; see module docs (backlog#1823)")]
 pub struct LocalUsageSnapshotMeta {
    /// Disk UUID stored as a string for simpler serialization.
    pub disk_id: String,
@@ -43,6 +55,7 @@ pub struct LocalUsageSnapshotMeta {

 /// Usage snapshot produced by a single disk.
 #[derive(Debug, Clone, Serialize, Deserialize, Default)]
+#[allow(dead_code, reason = "unwired local usage-snapshot feature; see module docs (backlog#1823)")]
 pub struct LocalUsageSnapshot {
    /// Format version recorded in the snapshot.
    pub format_version: u32,
@@ -64,6 +77,7 @@ pub struct LocalUsageSnapshot {
    pub objects_total_size: u64,
 }

+#[allow(dead_code, reason = "unwired local usage-snapshot feature; see module docs (backlog#1823)")]
 impl LocalUsageSnapshot {
    /// Create an empty snapshot with the default format version filled in.
    pub fn new(meta: LocalUsageSnapshotMeta) -> Self {
@@ -99,11 +113,13 @@ impl LocalUsageSnapshot {
 }

 /// Build the snapshot file name `<disk-id>.json`.
+#[allow(dead_code, reason = "unwired local usage-snapshot feature; see module docs (backlog#1823)")]
 pub fn snapshot_file_name(disk_id: &str) -> String {
    format!("{disk_id}.json")
 }

 /// Build the object path relative to `RUSTFS_META_BUCKET`, e.g. `datausage/<disk-id>.json`.
+#[allow(dead_code, reason = "unwired local usage-snapshot feature; see module docs (backlog#1823)")]
 pub fn snapshot_object_path(disk_id: &str) -> String {
    format!("{}/{}", DATA_USAGE_DIR, snapshot_file_name(disk_id))
 }
@@ -119,11 +135,13 @@ pub fn data_usage_state_dir(root: &Path) -> PathBuf {
 }

 /// Build the absolute path to the snapshot file for the provided disk ID.
+#[allow(dead_code, reason = "unwired local usage-snapshot feature; see module docs (backlog#1823)")]
 pub fn snapshot_path(root: &Path, disk_id: &str) -> PathBuf {
    data_usage_dir(root).join(snapshot_file_name(disk_id))
 }

 /// Read a snapshot from disk if it exists.
+#[allow(dead_code, reason = "unwired local usage-snapshot feature; see module docs (backlog#1823)")]
 pub async fn read_snapshot(root: &Path, disk_id: &str) -> Result<Option<LocalUsageSnapshot>> {
    let path = snapshot_path(root, disk_id);
    match fs::read(&path).await {
@@ -138,6 +156,7 @@ pub async fn read_snapshot(root: &Path, disk_id: &str) -> Result<Option<LocalUsa
 }

 /// Persist a snapshot to disk, creating directories as needed and overwriting any existing file.
+#[allow(dead_code, reason = "unwired local usage-snapshot feature; see module docs (backlog#1823)")]
 pub async fn write_snapshot(root: &Path, disk_id: &str, snapshot: &LocalUsageSnapshot) -> Result<()> {
    let dir = data_usage_dir(root);
    fs::create_dir_all(&dir).await.map_err(Error::other)?;
@@ -13,7 +13,6 @@
 // limitations under the License.

 // #730: scanner/data-usage state is partially migrated and still owns staged cache helpers.
-#![allow(dead_code)]

 pub mod local_snapshot;

@@ -34,8 +33,8 @@ use crate::{
 pub use local_snapshot::{LocalUsageSnapshot, read_snapshot as read_local_snapshot, snapshot_path};
 use rustfs_data_usage::{
    BucketTargetUsageInfo, BucketUsageInfo, CompressionTotalInfo, DATA_USAGE_OBJECT_NAME, DATA_USAGE_OBSERVED_OBJECT_NAME,
-    DataUsageCache, DataUsageEntry, DataUsageInfo, DiskUsageStatus, LEGACY_DATA_USAGE_OBJECT_NAME, SizeHistogram, SizeSummary,
-    VersionsHistogram, observed_data_usage_is_newer,
+    DataUsageCache, DataUsageInfo, DiskUsageStatus, LEGACY_DATA_USAGE_OBJECT_NAME, SizeHistogram, VersionsHistogram,
+    observed_data_usage_is_newer,
 };
 use rustfs_io_metrics::record_system_path_failure;
 use rustfs_utils::path::SLASH_SEPARATOR;
@@ -55,7 +54,6 @@ use tracing::{debug, error, info, instrument};
 // Data usage storage constants
 pub const DATA_USAGE_ROOT: &str = SLASH_SEPARATOR;
 const DATA_COMPRESSION_TOTAL_NAME: &str = ".compression.json";
-const DATA_USAGE_BLOOM_NAME: &str = ".bloomcycle.bin";
 pub const DATA_USAGE_CACHE_NAME: &str = ".usage-cache.bin";
 const DATA_USAGE_CACHE_TTL_SECS: u64 = 30;
 const LIVE_BUCKET_USAGE_MAX_ENTRIES: u64 = 1024;
@@ -313,11 +311,6 @@ lazy_static::lazy_static! {
        LEGACY_DATA_USAGE_OBJECT_NAME
    );
    static ref LEGACY_DATA_USAGE_OBJ_BACKUP_PATH: String = format!("{}.bkp", LEGACY_DATA_USAGE_OBJ_NAME_PATH.as_str());
-    pub static ref DATA_USAGE_BLOOM_NAME_PATH: String = format!("{}{}{}",
-        crate::disk::BUCKET_META_PREFIX,
-        SLASH_SEPARATOR,
-        DATA_USAGE_BLOOM_NAME
-    );
    pub static ref DATA_COMPRESSION_TOTAL_NAME_PATH: String = format!("{}{}{}",
        crate::disk::BUCKET_META_PREFIX,
        SLASH_SEPARATOR,
@@ -858,6 +851,10 @@ async fn resolve_loaded_snapshot_pair_with_source(
    }
 }

+#[allow(
+    dead_code,
+    reason = "primary/backup snapshot fallback asserted by this file's tests (backlog#1823)"
+)]
 async fn resolve_loaded_snapshot(
    primary: Result<Vec<u8>, Error>,
    backup: impl Future<Output = Result<Vec<u8>, Error>>,
@@ -1187,6 +1184,10 @@ pub async fn invalidate_admin_data_usage_snapshot_cache() {
 }

 /// Aggregate usage information from local disk snapshots.
+#[allow(
+    dead_code,
+    reason = "reached only through aggregate_local_snapshots, which has no caller (backlog#1823)"
+)]
 fn merge_snapshot(aggregated: &mut DataUsageInfo, mut snapshot: LocalUsageSnapshot, latest_update: &mut Option<SystemTime>) {
    if let Some(update) = snapshot.last_update
        && latest_update.is_none_or(|current| update > current)
@@ -1220,6 +1221,10 @@ fn merge_snapshot(aggregated: &mut DataUsageInfo, mut snapshot: LocalUsageSnapsh
    }
 }

+#[allow(
+    dead_code,
+    reason = "entry point of the local usage-snapshot feature, which has had no caller since it landed in #5307 (backlog#1823)"
+)]
 pub async fn aggregate_local_snapshots(store: Arc<ECStore>) -> Result<(Vec<DiskUsageStatus>, DataUsageInfo), Error> {
    let mut aggregated = DataUsageInfo::default();
    let mut latest_update: Option<SystemTime> = None;
@@ -1355,7 +1360,7 @@ impl BucketUsageAccumulator {
            return Ok(());
        }

-        let object_size = object.size.max(0) as u64;
+        let object_size = quota_object_size(object)?;
        self.current_live_versions = self.current_live_versions.saturating_add(1);
        self.size_histogram.add(object_size);
        self.total_size = self.total_size.saturating_add(object_size);
@@ -1385,6 +1390,31 @@ impl BucketUsageAccumulator {
    }
 }

+pub fn quota_object_size(object: &ObjectInfo) -> Result<u64, Error> {
+    let logical_size = u64::try_from(object.get_actual_size().map_err(Error::other)?).map_err(|_| Error::PartMissingOrCorrupt)?;
+    let persisted_part_size = if object.parts.is_empty() {
+        u64::try_from(object.size).map_err(|_| Error::PartMissingOrCorrupt)?
+    } else {
+        object.parts.iter().try_fold(0_u64, |total, part| {
+            // Compressed streaming objects persist -1 when the transformed
+            // part size is unknown. The physical part size remains a valid
+            // quota floor; reject only non-negative values that overflow.
+            let actual_size = if part.actual_size < 0 {
+                if object.is_compressed() {
+                    0
+                } else {
+                    return Err(Error::PartMissingOrCorrupt);
+                }
+            } else {
+                u64::try_from(part.actual_size).map_err(|_| Error::PartMissingOrCorrupt)?
+            };
+            let part_size = actual_size.max(u64::try_from(part.size).map_err(|_| Error::PartMissingOrCorrupt)?);
+            total.checked_add(part_size).ok_or(Error::PartMissingOrCorrupt)
+        })?
+    };
+    Ok(logical_size.max(persisted_part_size))
+}
+
 type UsageVersionPage = StorageListObjectVersionsInfo<ObjectInfo>;

 pub async fn compute_bucket_usage(store: Arc<ECStore>, bucket_name: &str) -> Result<BucketUsageInfo, Error> {
@@ -1742,11 +1772,6 @@ pub async fn record_bucket_object_write_unknown_previous_memory(bucket: &str, ne
    entry.pending_scanner_position = None;
 }

-/// Fast in-memory increment for immediate quota consistency.
-pub async fn increment_bucket_usage_memory(bucket: &str, size_increment: u64) {
-    record_bucket_object_write_memory(bucket, None, size_increment).await;
-}
-
 /// Fast in-memory update for successful object deletes.
 pub async fn record_bucket_object_delete_memory(bucket: &str, deleted_size: u64, removed_current_object: bool) {
    ensure_bucket_usage_cached(bucket).await;
@@ -1789,11 +1814,6 @@ pub async fn record_bucket_delete_marker_memory(bucket: &str) {
    entry.pending_scanner_position = None;
 }

-/// Fast in-memory decrement for immediate quota consistency
-pub async fn decrement_bucket_usage_memory(bucket: &str, size_decrement: u64) {
-    record_bucket_object_delete_memory(bucket, size_decrement, size_decrement > 0).await;
-}
-
 /// Get bucket usage from the authoritative cache for this topology.
 async fn get_persisted_bucket_usage(bucket: &str) -> Option<u64> {
    let store = runtime_sources::object_store_handle()?;
@@ -1988,91 +2008,6 @@ pub async fn apply_bucket_usage_memory_overlay(data_usage_info: &mut DataUsageIn
    apply_bucket_usage_memory_overlay_if_authoritative(data_usage_info, authoritative).await;
 }

-/// Sync memory cache with backend data (called by scanner)
-pub async fn sync_memory_cache_with_backend() -> Result<(), Error> {
-    if let Some(store) = runtime_sources::object_store_handle() {
-        match load_data_usage_from_backend(store.clone()).await {
-            Ok(data_usage_info) => {
-                replace_bucket_usage_memory_from_info(&data_usage_info).await;
-            }
-            Err(e) => {
-                debug!("Failed to sync memory cache with backend: {}", e);
-            }
-        }
-    }
-    Ok(())
-}
-
-/// Create a data usage cache entry from size summary
-pub fn create_cache_entry_from_summary(summary: &SizeSummary) -> DataUsageEntry {
-    let mut entry = DataUsageEntry::default();
-    entry.add_sizes(summary);
-    entry
-}
-
-/// Convert data usage cache to DataUsageInfo
-pub fn cache_to_data_usage_info(
-    cache: &DataUsageCache,
-    path: &str,
-    buckets: &[crate::storage_api_contracts::bucket::BucketInfo],
-) -> DataUsageInfo {
-    let e = match cache.find(path) {
-        Some(e) => e,
-        None => return DataUsageInfo::default(),
-    };
-    let flat = cache.flatten(&e);
-
-    let mut buckets_usage = HashMap::new();
-    for bucket in buckets.iter() {
-        let e = match cache.find(&bucket.name) {
-            Some(e) => e,
-            None => continue,
-        };
-        let flat = cache.flatten(&e);
-        let mut bui = BucketUsageInfo {
-            size: flat.size as u64,
-            versions_count: flat.versions as u64,
-            objects_count: flat.objects as u64,
-            delete_markers_count: flat.delete_markers as u64,
-            object_size_histogram: flat.obj_sizes.to_map(),
-            object_versions_histogram: flat.obj_versions.to_map(),
-            ..Default::default()
-        };
-
-        if let Some(rs) = &flat.replication_stats {
-            bui.replica_size = rs.replica_size;
-            bui.replica_count = rs.replica_count;
-
-            for (arn, stat) in rs.targets.iter() {
-                bui.replication_info.insert(
-                    arn.clone(),
-                    BucketTargetUsageInfo {
-                        replication_pending_size: stat.pending_size,
-                        replicated_size: stat.replicated_size,
-                        replication_failed_size: stat.failed_size,
-                        replication_pending_count: stat.pending_count,
-                        replication_failed_count: stat.failed_count,
-                        replicated_count: stat.replicated_count,
-                        ..Default::default()
-                    },
-                );
-            }
-        }
-        buckets_usage.insert(bucket.name.clone(), bui);
-    }
-
-    DataUsageInfo {
-        last_update: cache.info.last_update,
-        objects_total_count: flat.objects as u64,
-        versions_total_count: flat.versions as u64,
-        delete_markers_total_count: flat.delete_markers as u64,
-        objects_total_size: flat.size as u64,
-        buckets_count: e.children.len() as u64,
-        buckets_usage,
-        ..Default::default()
-    }
-}
-
 // Helper functions for DataUsageCache operations
 pub async fn load_data_usage_cache(store: &crate::set_disk::SetDisks, name: &str) -> crate::error::Result<DataUsageCache> {
    use crate::disk::{BUCKET_META_PREFIX, RUSTFS_META_BUCKET};
@@ -3124,6 +3059,102 @@ mod tests {
        assert_eq!(usage.object_versions_histogram.get("BETWEEN_1000_AND_10000"), Some(&1));
    }

+    #[test]
+    fn bucket_usage_uses_the_larger_of_logical_and_physical_size() {
+        let mut metadata = HashMap::new();
+        rustfs_utils::http::insert_str(
+            &mut metadata,
+            rustfs_utils::http::SUFFIX_COMPRESSION,
+            "klauspost/compress/s2".to_string(),
+        );
+        rustfs_utils::http::insert_str(&mut metadata, rustfs_utils::http::SUFFIX_ACTUAL_SIZE, "4096".to_string());
+        let object = ObjectInfo {
+            name: "compressed".to_string(),
+            size: 128,
+            user_defined: Arc::new(metadata),
+            ..Default::default()
+        };
+        let mut usage = BucketUsageAccumulator::default();
+        usage
+            .record("bucket", &object)
+            .expect("valid compressed metadata should be counted");
+        assert_eq!(usage.finish().size, 4096);
+
+        let mut framed_metadata = HashMap::new();
+        rustfs_utils::http::insert_str(
+            &mut framed_metadata,
+            rustfs_utils::http::SUFFIX_COMPRESSION,
+            "klauspost/compress/s2".to_string(),
+        );
+        rustfs_utils::http::insert_str(&mut framed_metadata, rustfs_utils::http::SUFFIX_ACTUAL_SIZE, "1".to_string());
+        let framed = ObjectInfo {
+            name: "framed".to_string(),
+            size: 17,
+            user_defined: Arc::new(framed_metadata),
+            ..Default::default()
+        };
+        assert_eq!(quota_object_size(&framed).expect("physical framing must remain quota-accounted"), 17);
+
+        let legacy_compressed_part = ObjectInfo {
+            name: "legacy-compressed-part".to_string(),
+            size: 1,
+            user_defined: Arc::new((*framed.user_defined).clone()),
+            parts: Arc::new(vec![rustfs_filemeta::ObjectPartInfo {
+                size: 1,
+                actual_size: -1,
+                ..Default::default()
+            }]),
+            ..Default::default()
+        };
+        assert_eq!(
+            quota_object_size(&legacy_compressed_part).expect("unknown compressed part size is a valid sentinel"),
+            1
+        );
+
+        let uncompressed_negative_part = ObjectInfo {
+            name: "uncompressed-negative-part".to_string(),
+            size: 1,
+            parts: Arc::new(vec![rustfs_filemeta::ObjectPartInfo {
+                size: 1,
+                actual_size: -1,
+                ..Default::default()
+            }]),
+            ..Default::default()
+        };
+        assert!(matches!(quota_object_size(&uncompressed_negative_part), Err(Error::PartMissingOrCorrupt)));
+
+        let mut corrupt_metadata = (*object.user_defined).clone();
+        rustfs_utils::http::insert_str(&mut corrupt_metadata, rustfs_utils::http::SUFFIX_ACTUAL_SIZE, "-1".to_string());
+        let corrupt = ObjectInfo {
+            user_defined: Arc::new(corrupt_metadata),
+            ..object
+        };
+        assert!(matches!(quota_object_size(&corrupt), Err(Error::PartMissingOrCorrupt)));
+
+        let mut poisoned_metadata = HashMap::new();
+        rustfs_utils::http::insert_str(
+            &mut poisoned_metadata,
+            rustfs_utils::http::SUFFIX_COMPRESSION,
+            "klauspost/compress/s2".to_string(),
+        );
+        rustfs_utils::http::insert_str(&mut poisoned_metadata, rustfs_utils::http::SUFFIX_ACTUAL_SIZE, "1".to_string());
+        let poisoned = ObjectInfo {
+            name: "legacy-swift-metadata".to_string(),
+            size: 4096,
+            user_defined: Arc::new(poisoned_metadata),
+            parts: Arc::new(vec![rustfs_filemeta::ObjectPartInfo {
+                size: 4096,
+                actual_size: 4096,
+                ..Default::default()
+            }]),
+            ..Default::default()
+        };
+        assert_eq!(
+            quota_object_size(&poisoned).expect("persisted part accounting must bound legacy user metadata"),
+            4096
+        );
+    }
+
    #[tokio::test]
    #[serial]
    async fn live_bucket_usage_refreshes_are_coalesced_only_while_in_flight() {
@@ -653,6 +653,7 @@ fn reconcile_servers_with_endpoint_topology(
    (added, report)
 }

+#[allow(dead_code, reason = "exercised by this file's topology tests (backlog#1823)")]
 fn server_topology_completeness_report(
    servers: &[ServerProperties],
    endpoints: &EndpointServerPools,
@@ -46,21 +46,49 @@ pub(crate) const GET_CODEC_STREAMING_OBJECT_CLASS_MULTIPART: &str = "multipart";
 pub(crate) const GET_STAGE_DECODE: &str = "decode";
 pub(crate) const GET_STAGE_EMIT: &str = "emit";
 pub(crate) const GET_STAGE_FILL: &str = "fill";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_FIRST_BYTE: &str = "first_byte";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_FIRST_METADATA_RESPONSE: &str = "first_metadata_response";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_FIRST_VALID_METADATA_RESPONSE: &str = "first_valid_metadata_response";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_FIRST_SHARD_READ: &str = "first_shard_read";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_FULL_BODY: &str = "full_body";
 pub(crate) const GET_STAGE_INLINE_PREPARE: &str = "inline_prepare";
 pub(crate) const GET_STAGE_LOCK_ACQUIRE: &str = "lock_acquire";
 pub(crate) const GET_STAGE_METADATA: &str = "metadata";
 pub(crate) const GET_STAGE_METADATA_CACHE_LOOKUP: &str = "metadata_cache_lookup";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_METADATA_FANOUT: &str = "metadata_fanout";
 pub(crate) const GET_STAGE_METADATA_RESOLVE: &str = "metadata_resolve";
 pub(crate) const GET_STAGE_OBJECT_INFO: &str = "object_info";
 pub(crate) const GET_STAGE_OUTPUT_LOCK_WAIT: &str = "output_lock_wait";
 pub(crate) const GET_STAGE_OUTPUT_POLL: &str = "output_poll";
 pub(crate) const GET_STAGE_PATH_DECISION: &str = "path_decision";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_QUORUM_REACHED: &str = "quorum_reached";
 pub(crate) const GET_STAGE_RANGE: &str = "range";
 pub(crate) const GET_STAGE_READER_SETUP: &str = "reader_setup";
@@ -84,12 +112,28 @@ pub(crate) const GET_STAGE_READER_STREAM_FIRST_READ: &str = "reader_stream_first
 pub(crate) const GET_STAGE_READER_TASK_BITROT_READER_INIT: &str = "reader_task_bitrot_reader_init";
 pub(crate) const GET_STAGE_READER_TASK_FILE_OPEN: &str = "reader_task_file_open";
 pub(crate) const GET_STAGE_READER_TASK_READER_CONSTRUCTION: &str = "reader_task_reader_construction";
+pub(crate) const GET_STAGE_READ_VERSION_DECODE: &str = "read_version_decode";
+pub(crate) const GET_STAGE_READ_VERSION_PATH_CHECK: &str = "read_version_path_check";
+pub(crate) const GET_STAGE_READ_VERSION_PATH_RESOLVE: &str = "read_version_path_resolve";
+pub(crate) const GET_STAGE_READ_VERSION_XLMETA_READ: &str = "read_version_xlmeta_read";
 pub(crate) const GET_STAGE_RECONSTRUCT: &str = "reconstruct";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_RESPONSE_HANDOFF: &str = "response_handoff";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_SLOWEST_METADATA_RESPONSE: &str = "slowest_metadata_response";
 pub(crate) const GET_STAGE_STRIPE_READ: &str = "stripe_read";
 pub(crate) const GET_STAGE_STRIPE_READ_FIRST_SHARD: &str = "stripe_read_first_shard";
 pub(crate) const GET_STAGE_STRIPE_READ_QUORUM: &str = "stripe_read_quorum";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const GET_STAGE_BITROT_VERIFY: &str = "bitrot_verify";

 pub(crate) const GET_READER_BUFFER_OUTPUT: &str = "output";
@@ -146,6 +190,17 @@ pub(crate) const GET_METADATA_CACHE_REASON_VERSION_SUSPENDED: &str = "version_su
 pub(crate) const GET_METADATA_CACHE_REASON_VERSIONED: &str = "versioned";
 pub(crate) const GET_METADATA_EARLY_STOP_REASON_CONFLICTING_METADATA: &str = "conflicting_metadata";
 pub(crate) const GET_METADATA_EARLY_STOP_REASON_DELETE_MARKER: &str = "delete_marker";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_BODY_VERIFY: &str = "data_read_inline_body_verify";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_DELETED: &str = "data_read_inline_deleted";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_GEOMETRY: &str = "data_read_inline_geometry";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_IDENTITY_MISMATCH: &str = "data_read_inline_identity_mismatch";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_MISSING_PAYLOAD: &str = "data_read_inline_missing_payload";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_MISSING_SHARD: &str = "data_read_inline_missing_shard";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_NOT_INLINE: &str = "data_read_inline_not_inline";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_PART_SHAPE: &str = "data_read_inline_part_shape";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_REMOTE: &str = "data_read_inline_remote";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_SIZE: &str = "data_read_inline_size";
+pub(crate) const GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_TRANSFORMED: &str = "data_read_inline_transformed";
 pub(crate) const GET_METADATA_EARLY_STOP_REASON_ERROR: &str = "error";
 pub(crate) const GET_METADATA_EARLY_STOP_REASON_INSUFFICIENT_QUORUM: &str = "insufficient_quorum";
 pub(crate) const GET_METADATA_EARLY_STOP_REASON_NOT_FOUND: &str = "not_found";
@@ -155,8 +210,20 @@ pub(crate) const GET_METADATA_EARLY_STOP_REASON_VERSION_NOT_FOUND: &str = "versi
 pub(crate) const GET_METADATA_EARLY_STOP_REASON_VERSION_MATCH_QUORUM: &str = "version_match_quorum";

 /// Early-stop active state labels
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const EARLY_STOP_ACTIVE_HIT: &str = "hit";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const EARLY_STOP_ACTIVE_MISS: &str = "miss";
+#[allow(
+    dead_code,
+    reason = "GET stage vocabulary; value pinned by this file's tests, no writer yet (backlog#1823)"
+)]
 pub(crate) const EARLY_STOP_ACTIVE_DISABLED: &str = "disabled";

 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
@@ -442,6 +509,10 @@ mod tests {
        assert_eq!(GET_STAGE_QUORUM_REACHED, "quorum_reached");
        assert_eq!(GET_STAGE_RANGE, "range");
        assert_eq!(GET_STAGE_READER_SETUP, "reader_setup");
+        assert_eq!(GET_STAGE_READ_VERSION_DECODE, "read_version_decode");
+        assert_eq!(GET_STAGE_READ_VERSION_PATH_CHECK, "read_version_path_check");
+        assert_eq!(GET_STAGE_READ_VERSION_PATH_RESOLVE, "read_version_path_resolve");
+        assert_eq!(GET_STAGE_READ_VERSION_XLMETA_READ, "read_version_xlmeta_read");
        assert_eq!(GET_STAGE_RECONSTRUCT, "reconstruct");
        assert_eq!(GET_STAGE_RESPONSE_HANDOFF, "response_handoff");
        assert_eq!(GET_STAGE_SLOWEST_METADATA_RESPONSE, "slowest_metadata_response");
@@ -491,6 +562,32 @@ mod tests {
        assert_eq!(GET_METADATA_CACHE_REASON_VERSIONED, "versioned");
        assert_eq!(GET_METADATA_EARLY_STOP_REASON_CONFLICTING_METADATA, "conflicting_metadata");
        assert_eq!(GET_METADATA_EARLY_STOP_REASON_DELETE_MARKER, "delete_marker");
+        assert_eq!(
+            GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_BODY_VERIFY,
+            "data_read_inline_body_verify"
+        );
+        assert_eq!(GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_DELETED, "data_read_inline_deleted");
+        assert_eq!(GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_GEOMETRY, "data_read_inline_geometry");
+        assert_eq!(
+            GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_IDENTITY_MISMATCH,
+            "data_read_inline_identity_mismatch"
+        );
+        assert_eq!(
+            GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_MISSING_PAYLOAD,
+            "data_read_inline_missing_payload"
+        );
+        assert_eq!(
+            GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_MISSING_SHARD,
+            "data_read_inline_missing_shard"
+        );
+        assert_eq!(GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_NOT_INLINE, "data_read_inline_not_inline");
+        assert_eq!(GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_PART_SHAPE, "data_read_inline_part_shape");
+        assert_eq!(GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_REMOTE, "data_read_inline_remote");
+        assert_eq!(GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_SIZE, "data_read_inline_size");
+        assert_eq!(
+            GET_METADATA_EARLY_STOP_REASON_DATA_READ_INLINE_TRANSFORMED,
+            "data_read_inline_transformed"
+        );
        assert_eq!(GET_METADATA_EARLY_STOP_REASON_ERROR, "error");
        assert_eq!(GET_METADATA_EARLY_STOP_REASON_INSUFFICIENT_QUORUM, "insufficient_quorum");
        assert_eq!(GET_METADATA_EARLY_STOP_REASON_NOT_FOUND, "not_found");
@@ -13,8 +13,6 @@
 // limitations under the License.

 // #730: diagnostics constants are staged for request-path telemetry migration.
-#![allow(dead_code)]

 pub(crate) mod admin_server_info;
 pub(crate) mod get;
-pub(crate) mod pool;
@@ -1,30 +0,0 @@
-// Copyright 2024 RustFS Team
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//! BytesPool metric label constants.
-//!
-//! These constants are used when recording pool acquisition and return
-//! metrics to avoid string allocations and ensure label consistency.
-
-/// BytesPool tier labels
-pub const POOL_TIER_SMALL: &str = "small";
-pub const POOL_TIER_MEDIUM: &str = "medium";
-pub const POOL_TIER_LARGE: &str = "large";
-pub const POOL_TIER_XLARGE: &str = "xlarge";
-
-/// BytesPool outcome labels
-pub const POOL_OUTCOME_HIT: &str = "hit";
-pub const POOL_OUTCOME_MISS: &str = "miss";
-pub const POOL_OUTCOME_RECYCLED: &str = "recycled";
-pub const POOL_OUTCOME_DROPPED: &str = "dropped";
@@ -241,6 +241,40 @@ pub fn get_drive_list_dir_timeout() -> Duration {
    )
 }

+pub(crate) trait DiskStoreRenameDataExt {
+    async fn rename_data_borrowed(
+        &self,
+        src_volume: &str,
+        src_path: &str,
+        fi: &FileInfo,
+        dst_volume: &str,
+        dst_path: &str,
+    ) -> Result<RenameDataResp>;
+}
+
+impl DiskStoreRenameDataExt for LocalDiskWrapper {
+    async fn rename_data_borrowed(
+        &self,
+        src_volume: &str,
+        src_path: &str,
+        fi: &FileInfo,
+        dst_volume: &str,
+        dst_path: &str,
+    ) -> Result<RenameDataResp> {
+        self.track_disk_health_mutation(
+            "rename_data",
+            DiskMetricMutation::Write,
+            || async {
+                self.disk
+                    .rename_data_borrowed(src_volume, src_path, fi, dst_volume, dst_path)
+                    .await
+            },
+            get_max_timeout_duration(),
+        )
+        .await
+    }
+}
+
 pub fn get_drive_walkdir_timeout() -> Duration {
    get_drive_timeout_duration(
        rustfs_config::ENV_DRIVE_WALKDIR_TIMEOUT_SECS,
@@ -603,14 +637,23 @@ impl Default for DiskOperationMetrics {
 }

 impl DiskOperationMetrics {
+    #[allow(
+        dead_code,
+        reason = "internal metrics recorder reached only from record() below (backlog#1823)"
+    )]
    fn record_call(&mut self) {
        self.lifetime_calls.fetch_add(1, Ordering::Relaxed);
    }

+    #[allow(
+        dead_code,
+        reason = "internal metrics recorder reached only from record() below (backlog#1823)"
+    )]
    fn record_latency(&mut self, now_sec: u64, elapsed: Duration) {
        self.record_latency_atomic(now_sec, elapsed);
    }

+    #[allow(dead_code, reason = "metrics roll-up with no caller in this port (backlog#1823)")]
    fn record(&mut self, now_sec: u64, elapsed: Duration) {
        self.record_call();
        self.record_latency(now_sec, elapsed);
@@ -736,6 +779,7 @@ impl DiskHealthTracker {
    }

    /// Set disk as faulty
+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    pub fn set_faulty(&self) {
        self.status.store(DISK_HEALTH_FAULTY, Ordering::Release);
    }
@@ -816,6 +860,7 @@ impl DiskHealthTracker {
        became_offline
    }

+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    pub fn mark_offline(&self, endpoint: &Endpoint, reason: &'static str) -> bool {
        let current = self.runtime_state();
        if current == RuntimeDriveHealthState::Offline {
@@ -946,11 +991,13 @@ impl DiskHealthTracker {
    }

    /// Get waiting operations count
+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    pub fn waiting_count(&self) -> u32 {
        self.waiting.load(Ordering::Relaxed)
    }

    /// Get last success timestamp
+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    pub fn last_success(&self) -> i64 {
        self.last_success.load(Ordering::Acquire)
    }
@@ -992,21 +1039,6 @@ impl Default for DiskHealthTracker {
    }
 }

-/// Health check context key for tracking disk operations
-#[derive(Debug, Clone)]
-struct HealthDiskCtxKey;
-
-#[derive(Debug)]
-struct HealthDiskCtxValue {
-    last_success: Arc<AtomicI64>,
-}
-
-impl HealthDiskCtxValue {
-    fn log_success(&self) {
-        self.last_success.store(current_unix_nanos(), Ordering::Relaxed);
-    }
-}
-
 /// LocalDiskWrapper wraps a DiskStore with health tracking capabilities.
 /// This is similar to Go's xlStorageDiskIDCheck.
 #[derive(Debug, Clone)]
@@ -1038,10 +1070,6 @@ impl LocalDiskWrapper {
        )
    }

-    pub(crate) fn new_with_health(disk: Arc<LocalDisk>, health_check: bool, health: Arc<DiskHealthTracker>) -> Self {
-        Self::new_with_health_and_metrics(disk, health_check, health, Arc::new(DiskHealthMetricEpoch::default()))
-    }
-
    pub(crate) fn new_with_reconnect_state(
        disk: Arc<LocalDisk>,
        health_check: bool,
@@ -1404,20 +1432,6 @@ impl LocalDiskWrapper {
        }
    }

-    async fn check_id(&self, want_id: Option<Uuid>) -> Result<()> {
-        if want_id.is_none() {
-            return Ok(());
-        }
-
-        let stored_disk_id = self.disk.get_disk_id().await?;
-
-        if stored_disk_id != want_id {
-            return Err(Error::other(format!("Disk ID mismatch wanted {want_id:?}, got {stored_disk_id:?}")));
-        }
-
-        Ok(())
-    }
-
    /// Check if disk ID is stale
    async fn check_disk_stale(&self) -> Result<()> {
        let Some(current_disk_id) = *self.disk_id.read().await else {
@@ -1985,13 +1999,8 @@ impl DiskAPI for LocalDiskWrapper {
        dst_volume: &str,
        dst_path: &str,
    ) -> Result<RenameDataResp> {
-        self.track_disk_health_mutation(
-            "rename_data",
-            DiskMetricMutation::Write,
-            || async { self.disk.rename_data(src_volume, src_path, fi, dst_volume, dst_path).await },
-            get_max_timeout_duration(),
-        )
-        .await
+        self.rename_data_borrowed(src_volume, src_path, &fi, dst_volume, dst_path)
+            .await
    }

    async fn list_dir(&self, origvolume: &str, volume: &str, dir_path: &str, count: i32) -> Result<Vec<String>> {
@@ -48,6 +48,7 @@ pub fn to_volume_error(io_err: std::io::Error) -> std::io::Error {
    }
 }

+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 pub fn to_disk_error(io_err: std::io::Error) -> std::io::Error {
    match io_err.kind() {
        std::io::ErrorKind::NotFound => DiskError::DiskNotFound.into(),
@@ -178,6 +178,7 @@ pub async fn remove(path: impl AsRef<Path>) -> io::Result<()> {
    }
 }

+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 pub async fn remove_all(path: impl AsRef<Path>) -> io::Result<()> {
    // Try remove_file first; fall back to remove_dir_all if it's a directory
    match fs::remove_file(path.as_ref()).await {
@@ -15,6 +15,11 @@
 use crate::config::storageclass::DEFAULT_INLINE_BLOCK;
 use crate::crash_inject::{self, CrashPoint};
 use crate::data_usage::local_snapshot::ensure_data_usage_layout;
+use crate::diagnostics::get::{
+    GET_OBJECT_PATH_INTERNAL_META, GET_OBJECT_PATH_LEGACY_DUPLEX, GET_STAGE_READ_VERSION_DECODE,
+    GET_STAGE_READ_VERSION_PATH_CHECK, GET_STAGE_READ_VERSION_PATH_RESOLVE, GET_STAGE_READ_VERSION_XLMETA_READ,
+    get_stage_timer_if_enabled, record_get_stage_duration_if_enabled,
+};
 #[cfg(test)]
 use crate::disk::HEALING_MARKER_PATH;
 use crate::disk::disk_store::{get_drive_walkdir_stall_timeout, get_object_disk_read_timeout};
@@ -22,17 +27,18 @@ use crate::disk::{
    BUCKET_META_PREFIX, CHECK_PART_FILE_CORRUPT, CHECK_PART_FILE_NOT_FOUND, CHECK_PART_SUCCESS, CHECK_PART_UNKNOWN,
    CHECK_PART_VOLUME_NOT_FOUND, CheckPartsResp, ConditionalFileUpdate, DataDirDeleteStatus, DeleteOptions, DiskAPI, DiskInfo,
    DiskInfoOptions, DiskLocation, DiskMetrics, FileInfoVersions, FileReader, FileWriter, MmapCopyStageMetrics, OldCurrentSize,
-    PART_TRANSACTION_NEW_META, PART_TRANSACTION_OLD_META, PART_TRANSACTION_ROLLBACK, PartTransactionAction, RUSTFS_META_BUCKET,
-    RUSTFS_META_TMP_BUCKET, RUSTFS_META_TMP_DELETED_BUCKET, ReadMultipleReq, ReadMultipleResp, ReadOptions, RenameDataResp,
-    STORAGE_FORMAT_FILE, STORAGE_FORMAT_FILE_BACKUP, SnapshotLeaseToken, UpdateMetadataOpts, VolumeInfo, WalkDirOptions,
-    conv_part_err_to_int,
+    PART_TRANSACTION_NEW_META, PART_TRANSACTION_OLD_META, PART_TRANSACTION_ROLLBACK, PartTransactionAction,
+    QUOTA_MUTATION_FENCE_METADATA_SUFFIX, RUSTFS_META_BUCKET, RUSTFS_META_TMP_BUCKET, RUSTFS_META_TMP_DELETED_BUCKET,
+    ReadMultipleReq, ReadMultipleResp, ReadOptions, RenameDataResp, STORAGE_FORMAT_FILE, STORAGE_FORMAT_FILE_BACKUP,
+    SnapshotLeaseToken, UpdateMetadataOpts, VolumeInfo, WalkDirOptions, conv_part_err_to_int,
    endpoint::Endpoint,
    error::{DiskError, Error, FileAccessDeniedWithContext, Result},
    error_conv::{to_access_error, to_file_error, to_unformatted_disk_error, to_volume_error},
    format::FormatV3,
    fs::{O_APPEND, O_CREATE, O_RDONLY, O_TRUNC, O_WRONLY, access, lstat, lstat_std, remove, remove_all_std, remove_std, rename},
-    os,
+    is_quota_mutation_fence_path, os,
    os::{check_path_length, is_dir_not_empty_error, is_empty_dir, is_root_disk, rename_all, rename_all_ignore_missing_source},
+    quota_mutation_fence_path,
 };
 use crate::erasure::coding::{self, bitrot_verify};
 use crate::runtime::sources as runtime_sources;
@@ -55,9 +61,7 @@ use std::collections::HashMap;
 use std::collections::HashSet;
 use std::fmt::Debug;
 use std::io::{Error as IoError, SeekFrom};
-#[cfg(target_os = "linux")]
-use std::sync::atomic::AtomicBool;
-use std::sync::atomic::{AtomicU32, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicU32, AtomicUsize, Ordering};
 use std::sync::{Arc, OnceLock};
 use std::time::Duration;
 use std::{
@@ -661,6 +665,7 @@ async fn remove_empty_directory_tree_under_mount_lease(
 }

 #[cfg(unix)]
+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 async fn remove_empty_directory_tree_with(
    root: &Path,
    before_descend: impl FnMut(&Path) -> std::io::Result<()>,
@@ -1012,13 +1017,29 @@ fn record_direct_read_page_fault_delta(path: &'static str, stage: &'static str,
 /// When enabled, shard reads bypass the page cache using O_DIRECT flag.
 /// Requires aligned buffers (typically 512 bytes or 4096 bytes).
 /// Default: false (uses page cache via mmap/pread).
+#[allow(
+    dead_code,
+    reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)"
+)]
 const ENV_RUSTFS_OBJECT_DIRECT_IO_READ_ENABLE: &str = "RUSTFS_OBJECT_DIRECT_IO_READ_ENABLE";
+#[allow(
+    dead_code,
+    reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)"
+)]
 const DEFAULT_RUSTFS_OBJECT_DIRECT_IO_READ_ENABLE: bool = false;

 /// Minimum shard size threshold for O_DIRECT reads.
 /// Only shards larger than this threshold will use O_DIRECT.
 /// Default: 4MB.
+#[allow(
+    dead_code,
+    reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)"
+)]
 const ENV_RUSTFS_OBJECT_DIRECT_IO_READ_THRESHOLD: &str = "RUSTFS_OBJECT_DIRECT_IO_READ_THRESHOLD";
+#[allow(
+    dead_code,
+    reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)"
+)]
 const DEFAULT_RUSTFS_OBJECT_DIRECT_IO_READ_THRESHOLD: usize = 4 * 1024 * 1024;

 /// Enable O_DIRECT for erasure shard / multipart part data writes (Linux only).
@@ -1032,7 +1053,15 @@ const DEFAULT_RUSTFS_OBJECT_DIRECT_IO_READ_THRESHOLD: usize = 4 * 1024 * 1024;
 /// EINVAL/EOPNOTSUPP (tmpfs, overlayfs, 9p, ...) latch the path off and fall
 /// back to buffered writes for the whole disk. Non-Linux always falls back.
 /// Default: false (buffered writes via the page cache, as before).
+#[allow(
+    dead_code,
+    reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)"
+)]
 const ENV_RUSTFS_OBJECT_DIRECT_IO_WRITE_ENABLE: &str = "RUSTFS_OBJECT_DIRECT_IO_WRITE_ENABLE";
+#[allow(
+    dead_code,
+    reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)"
+)]
 const DEFAULT_RUSTFS_OBJECT_DIRECT_IO_WRITE_ENABLE: bool = false;
 const ENV_RUSTFS_OBJECT_MMAP_POPULATE_ENABLE: &str = "RUSTFS_OBJECT_MMAP_POPULATE_ENABLE";
 const DEFAULT_RUSTFS_OBJECT_MMAP_POPULATE_ENABLE: bool = false;
@@ -1091,12 +1120,14 @@ macro_rules! cached_read_env {

 cached_read_env! {
    /// Check if O_DIRECT reads are enabled.
+    #[allow(dead_code, reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)")]
    fn is_direct_io_read_enabled() -> bool =
        rustfs_utils::get_env_bool(ENV_RUSTFS_OBJECT_DIRECT_IO_READ_ENABLE, DEFAULT_RUSTFS_OBJECT_DIRECT_IO_READ_ENABLE);
 }

 cached_read_env! {
    /// Check if O_DIRECT shard/part data writes are enabled.
+    #[allow(dead_code, reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)")]
    fn is_direct_io_write_enabled() -> bool =
        rustfs_utils::get_env_bool(ENV_RUSTFS_OBJECT_DIRECT_IO_WRITE_ENABLE, DEFAULT_RUSTFS_OBJECT_DIRECT_IO_WRITE_ENABLE);
 }
@@ -1452,6 +1483,7 @@ pub(crate) fn effective_durability(volume: &str) -> DurabilityMode {

 cached_read_env! {
    /// Get the O_DIRECT read threshold size.
+    #[allow(dead_code, reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)")]
    fn get_direct_io_read_threshold() -> usize =
        rustfs_utils::get_env_usize(ENV_RUSTFS_OBJECT_DIRECT_IO_READ_THRESHOLD, DEFAULT_RUSTFS_OBJECT_DIRECT_IO_READ_THRESHOLD);
 }
@@ -1669,12 +1701,20 @@ impl DirectIoWriteState {
 /// Target staging size for O_DIRECT writes, rounded up to the DIO alignment.
 /// Bounds the per-writer aligned bounce buffer and batches many shard blocks
 /// into one positioned write to keep the syscall count low.
+#[allow(
+    dead_code,
+    reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)"
+)]
 const DIRECT_WRITE_STAGING_BYTES: usize = 1024 * 1024;

 /// Aligned bounce-buffer capacity for a given DIO alignment: the target staging
 /// size rounded up to a whole multiple of `align` so the buffer address, every
 /// flushed batch length, and every write offset stay alignment-correct.
 /// Platform-independent (no O_DIRECT), so it is unit-tested on any host.
+#[allow(
+    dead_code,
+    reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)"
+)]
 fn direct_write_staging_capacity(align: usize) -> usize {
    debug_assert!(align.is_power_of_two() && align >= 512);
    DIRECT_WRITE_STAGING_BYTES.div_ceil(align) * align
@@ -1683,6 +1723,10 @@ fn direct_write_staging_capacity(align: usize) -> usize {
 /// Split `filled` staged bytes into the alignment-sized prefix written with
 /// O_DIRECT and the sub-alignment tail written buffered. Platform-independent,
 /// so the tail-boundary math is unit-tested on any host.
+#[allow(
+    dead_code,
+    reason = "platform-conditional: production callers are inside #[cfg(target_os = \"linux\")] blocks, so this reads as dead on non-Linux hosts (backlog#1823)"
+)]
 fn direct_write_tail_split(filled: usize, align: usize) -> (usize, usize) {
    let aligned = filled - (filled % align);
    (aligned, filled - aligned)
@@ -2024,14 +2068,17 @@ static RENAME_DATA_REMOVE_DST_BASE_BEFORE_COMMIT: std::sync::Mutex<Option<(Strin
 #[cfg(test)]
 type InlinePreparationHook = Box<dyn FnOnce() + Send>;
 #[cfg(test)]
+type RenameDataPublicationHookKey = (PathBuf, String, String);
+#[cfg(test)]
 static INLINE_PREPARATION_BEFORE_BACKUP: std::sync::LazyLock<std::sync::Mutex<HashMap<String, InlinePreparationHook>>> =
    std::sync::LazyLock::new(|| std::sync::Mutex::new(HashMap::new()));
 #[cfg(test)]
 static INLINE_BEFORE_FILE_SYNC_ADMISSION: std::sync::LazyLock<std::sync::Mutex<HashMap<String, InlinePreparationHook>>> =
    std::sync::LazyLock::new(|| std::sync::Mutex::new(HashMap::new()));
 #[cfg(test)]
-static RENAME_DATA_AFTER_FIRST_PUBLICATION: std::sync::LazyLock<std::sync::Mutex<HashMap<String, InlinePreparationHook>>> =
-    std::sync::LazyLock::new(|| std::sync::Mutex::new(HashMap::new()));
+static RENAME_DATA_AFTER_FIRST_PUBLICATION: std::sync::LazyLock<
+    std::sync::Mutex<HashMap<RenameDataPublicationHookKey, InlinePreparationHook>>,
+> = std::sync::LazyLock::new(|| std::sync::Mutex::new(HashMap::new()));
 #[cfg(test)]
 static OWNED_FILE_WRITE_BEFORE_OPEN: std::sync::LazyLock<std::sync::Mutex<HashMap<PathBuf, InlinePreparationHook>>> =
    std::sync::LazyLock::new(|| std::sync::Mutex::new(HashMap::new()));
@@ -2103,11 +2150,11 @@ fn set_inline_before_file_sync_admission(dst_path: &str, hook: impl FnOnce() + S
 }

 #[cfg(test)]
-fn set_rename_data_after_first_publication(dst_path: &str, hook: impl FnOnce() + Send + 'static) {
+fn set_rename_data_after_first_publication(root: &Path, dst_volume: &str, dst_path: &str, hook: impl FnOnce() + Send + 'static) {
    RENAME_DATA_AFTER_FIRST_PUBLICATION
        .lock()
        .expect("test publication hook lock should not be poisoned")
-        .insert(dst_path.to_string(), Box::new(hook));
+        .insert((root.to_path_buf(), dst_volume.to_string(), dst_path.to_string()), Box::new(hook));
 }

 #[cfg(test)]
@@ -2135,6 +2182,7 @@ fn set_delete_version_fail_after_data_staged(path: &str) {
 }

 #[cfg(test)]
+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 pub(crate) fn set_delete_version_fail_after_commit(root: &Path, path: &str) {
    DELETE_VERSION_FAIL_AFTER_COMMIT
        .lock()
@@ -2259,11 +2307,11 @@ fn run_inline_before_file_sync_admission(dst_path: &str) {
 }

 #[cfg(test)]
-fn run_rename_data_after_first_publication(dst_path: &str) {
+fn run_rename_data_after_first_publication(root: &Path, dst_volume: &str, dst_path: &str) {
    let hook = RENAME_DATA_AFTER_FIRST_PUBLICATION
        .lock()
        .expect("test publication hook lock should not be poisoned")
-        .remove(dst_path);
+        .remove(&(root.to_path_buf(), dst_volume.to_string(), dst_path.to_string()));
    if let Some(hook) = hook {
        hook();
    }
@@ -2361,9 +2409,6 @@ async fn remove_dst_base_before_commit(
 #[cfg(not(test))]
 fn run_inline_preparation_before_backup(_dst_path: &str) {}

-#[cfg(not(test))]
-fn run_rename_data_after_first_publication(_dst_path: &str) {}
-
 #[cfg(not(test))]
 fn should_fail_after_delete_data_staged(_path: &str) -> bool {
    false
@@ -2443,6 +2488,10 @@ enum SyncMode {
    FileOnly,
 }

+#[allow(
+    dead_code,
+    reason = "reclaim bookkeeping fields written by Drop but never read back (backlog#1823)"
+)]
 struct FileCacheReclaimWriter {
    inner: File,
    reclaim_len: usize,
@@ -2450,6 +2499,10 @@ struct FileCacheReclaimWriter {
    reclaimed: bool,
 }

+#[allow(
+    dead_code,
+    reason = "reclaim bookkeeping fields written by Drop but never read back (backlog#1823)"
+)]
 struct FileCacheReclaimReader {
    inner: File,
    reclaim_offset: u64,
@@ -2515,6 +2568,10 @@ impl<R: AsyncRead + Unpin> AsyncRead for StallTimeoutReader<R> {
    }
 }

+#[allow(
+    dead_code,
+    reason = "reclaim metrics emitter reached only from the Linux-gated reclaim paths (backlog#1823)"
+)]
 fn record_file_cache_reclaim_success(kind: &'static str, reclaim_len: usize, started: std::time::Instant) {
    // Runs per read-stream page-cache reclaim window; skip the whole emission
    // (three metric-key constructions) when general metrics are disabled.
@@ -3067,6 +3124,7 @@ impl LocalIoBackend for StdBackend {
            use memmap2::MmapOptions;
            use std::time::{Duration as StdDuration, Instant as StdInstant};

+            #[allow(dead_code, reason = "mmap copy result slot kept beside the mapping it owns (backlog#1823)")]
            struct MmapCopyReadResult {
                bytes: Bytes,
                access_check_duration: StdDuration,
@@ -4700,6 +4758,10 @@ fn build_local_io_backend(root: PathBuf) -> Arc<dyn LocalIoBackend> {
    Arc::new(StdBackend::new(root))
 }

+#[allow(
+    dead_code,
+    reason = "path cache and cwd slots retained beside the disk root they derive from (backlog#1823)"
+)]
 pub struct LocalDisk {
    pub root: PathBuf,
    publication_root: os::PublicationRoot,
@@ -4751,6 +4813,25 @@ struct SnapshotLeaseEntry {
    tokens: HashSet<SnapshotLeaseToken>,
    pending_delete: Option<DeleteOptions>,
    deleting: bool,
+    mutation_fence: Option<Arc<QuotaMutationFenceState>>,
+}
+
+#[derive(Default)]
+struct QuotaMutationFenceState {
+    revoked: AtomicBool,
+    running: AtomicUsize,
+    notify: Notify,
+}
+
+struct QuotaMutationFenceClaim {
+    state: Arc<QuotaMutationFenceState>,
+}
+
+impl Drop for QuotaMutationFenceClaim {
+    fn drop(&mut self) {
+        self.state.running.fetch_sub(1, Ordering::AcqRel);
+        self.state.notify.notify_waiters();
+    }
 }

 #[derive(Default)]
@@ -5467,6 +5548,7 @@ impl LocalDisk {
        Ok(Self::resolve_abs_path_from(&self.root, path.as_ref()))
    }

+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    fn io_resolve_abs_path(&self, path: impl AsRef<Path>) -> PathBuf {
        let path_ref = path.as_ref();
        let path_str = path_ref.to_string_lossy();
@@ -5544,15 +5626,24 @@ impl LocalDisk {
    }

    // Check if a path is valid
+    #[allow(
+        dead_code,
+        reason = "method wrapper over the live free function check_local_disk_valid_path; no caller in this port (backlog#1823)"
+    )]
    fn check_valid_path<P: AsRef<Path>>(&self, path: P) -> Result<()> {
        check_local_disk_valid_path(self.io_root(), path)
    }

+    #[allow(
+        dead_code,
+        reason = "method wrapper over the live free function reject_local_disk_symlink_components; no caller in this port (backlog#1823)"
+    )]
    fn reject_symlink_components(&self, path: &Path) -> Result<()> {
        reject_local_disk_symlink_components(self.io_root(), path)
    }

    // Batch path generation with single lock acquisition
+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    fn get_object_paths_batch(&self, requests: &[(String, String)]) -> Result<Vec<PathBuf>> {
        let mut results = Vec::with_capacity(requests.len());
        let mut cache_misses = Vec::new();
@@ -6465,6 +6556,7 @@ impl LocalDisk {
        Ok(f)
    }

+    #[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
    async fn open_file_read_only(&self, path: impl AsRef<Path>) -> Result<File> {
        let f = super::fs::open_file(path.as_ref(), O_RDONLY).await.map_err(to_file_error)?;
        Ok(f)
@@ -7315,6 +7407,34 @@ fn normalize_path_components(path: impl AsRef<Path>) -> PathBuf {
 }

 impl LocalDisk {
+    async fn claim_quota_mutation_fence(
+        &self,
+        volume: &str,
+        path: &str,
+        token: SnapshotLeaseToken,
+    ) -> Result<Arc<QuotaMutationFenceClaim>> {
+        let key = SnapshotLeaseKey {
+            volume: RUSTFS_META_BUCKET.to_string(),
+            path: quota_mutation_fence_path(volume, path),
+        };
+        let state = {
+            let registry = self.snapshot_leases.lock().await;
+            let entry = registry.entries.get(&key).ok_or(DiskError::FileNotFound)?;
+            let state = entry.mutation_fence.as_ref().ok_or(DiskError::FileNotFound)?;
+            if !entry.tokens.contains(&token) || state.revoked.load(Ordering::Acquire) {
+                return Err(DiskError::FileNotFound);
+            }
+            state.running.fetch_add(1, Ordering::AcqRel);
+            Arc::clone(state)
+        };
+        if state.revoked.load(Ordering::Acquire) {
+            state.running.fetch_sub(1, Ordering::AcqRel);
+            state.notify.notify_waiters();
+            return Err(DiskError::FileNotFound);
+        }
+        Ok(Arc::new(QuotaMutationFenceClaim { state }))
+    }
+
    async fn reserve_version_delete(&self, volume: &str, object: &str, data_dir: Uuid, rollback_dir: Uuid) -> Result<bool> {
        let path = format!("{object}/{data_dir}");
        let data_path = self.io_get_object_path(volume, &path)?;
@@ -8638,17 +8758,41 @@ impl DiskAPI for LocalDisk {
        &self,
        src_volume: &str,
        src_path: &str,
-        mut fi: FileInfo,
+        fi: FileInfo,
        dst_volume: &str,
        dst_path: &str,
    ) -> Result<RenameDataResp> {
        crate::hp_guard!("LocalDisk::rename_data");
+        let mut fi = fi;
        // A non-force DeleteBucket must not remove a directory while a local
        // object commit is publishing into it. The peer's empty scan remains
        // optimistic; this lease establishes the local commit/delete order and
        // remains owned by any blocking syscall that outlives async cancellation.
        let destination_object_path = self.io_get_object_path(dst_volume, dst_path)?;
+        let quota_fence_token =
+            match rustfs_utils::http::metadata_compat::get_consistent_str(&fi.metadata, QUOTA_MUTATION_FENCE_METADATA_SUFFIX) {
+                Some(value) => {
+                    let token = Uuid::parse_str(value).map_err(|_| DiskError::FileCorrupt)?;
+                    Some(SnapshotLeaseToken::from_slice(token.as_bytes())?)
+                }
+                None if rustfs_utils::http::metadata_compat::contains_key_str(
+                    &fi.metadata,
+                    QUOTA_MUTATION_FENCE_METADATA_SUFFIX,
+                ) =>
+                {
+                    return Err(DiskError::FileCorrupt);
+                }
+                None => None,
+            };
+        rustfs_utils::http::metadata_compat::remove_str(&mut fi.metadata, QUOTA_MUTATION_FENCE_METADATA_SUFFIX);
+        let quota_fence_claim = match quota_fence_token {
+            Some(token) => Some(self.claim_quota_mutation_fence(dst_volume, dst_path, token).await?),
+            None => None,
+        };
        let mutation_lease = os::acquire_rename_data_mutation_lease(&self.root, dst_volume, &destination_object_path).await;
+        if let Some(claim) = quota_fence_claim {
+            mutation_lease.attach_external_guard(claim);
+        }
        if fi.is_legacy_indexed_delete_marker() {
            fi.erasure.index = 0;
        }
@@ -8941,8 +9085,9 @@ impl DiskAPI for LocalDisk {
                .await?;
                return Err(err);
            }
+            #[cfg(test)]
            if has_data_dir_path.is_some() {
-                run_rename_data_after_first_publication(dst_path);
+                run_rename_data_after_first_publication(&self.root, dst_volume, dst_path);
            }

            // Crash-consistency injection: hard power loss after the data dir
@@ -9375,7 +9520,8 @@ impl DiskAPI for LocalDisk {
                    let _ = remove_file_if_exists(staged_backup);
                    return Err(err);
                }
-                run_rename_data_after_first_publication(dst_path);
+                #[cfg(test)]
+                run_rename_data_after_first_publication(&self.root, dst_volume, dst_path);
                if sync {
                    file_sync_admission = Some(
                        os::acquire_file_sync_admission(self.file_sync_permits.clone())
@@ -9638,11 +9784,26 @@ impl DiskAPI for LocalDisk {
    }

    async fn acquire_snapshot_lease(&self, volume: &str, path: &str) -> Result<SnapshotLeaseToken> {
-        let file_path = self.io_get_object_path(volume, path)?;
        let key = SnapshotLeaseKey {
            volume: volume.to_string(),
            path: path.to_string(),
        };
+        if volume == RUSTFS_META_BUCKET && is_quota_mutation_fence_path(path) {
+            let mut registry = self.snapshot_leases.lock().await;
+            let entry = registry.entries.entry(key).or_default();
+            let state = entry
+                .mutation_fence
+                .get_or_insert_with(|| Arc::new(QuotaMutationFenceState::default()));
+            if state.revoked.load(Ordering::Acquire) {
+                return Err(DiskError::FileNotFound);
+            }
+            let token = SnapshotLeaseToken::new();
+            entry.tokens.insert(token);
+            return Ok(token);
+        }
+
+        let file_path = self.io_get_object_path(volume, path)?;
+        let _mutation_lease = os::acquire_rename_data_mutation_lease(&self.root, volume, &file_path).await;
        let token = {
            let mut registry = self.snapshot_leases.lock().await;
            if registry.entries.get(&key).is_some_and(|entry| entry.deleting) {
@@ -9670,6 +9831,48 @@ impl DiskAPI for LocalDisk {
            volume: volume.to_string(),
            path: path.to_string(),
        };
+        if volume == RUSTFS_META_BUCKET && is_quota_mutation_fence_path(path) {
+            if !token.is_revoke_all() {
+                let mut registry = self.snapshot_leases.lock().await;
+                let Some(entry) = registry.entries.get_mut(&key) else {
+                    return Ok(());
+                };
+                entry.tokens.remove(&token);
+                let removable = entry.tokens.is_empty()
+                    && entry
+                        .mutation_fence
+                        .as_ref()
+                        .is_none_or(|state| state.running.load(Ordering::Acquire) == 0);
+                if removable {
+                    registry.entries.remove(&key);
+                }
+                return Ok(());
+            }
+            let state = {
+                let mut registry = self.snapshot_leases.lock().await;
+                let Some(entry) = registry.entries.get_mut(&key) else {
+                    return Ok(());
+                };
+                let Some(state) = entry.mutation_fence.as_ref().cloned() else {
+                    registry.entries.remove(&key);
+                    return Ok(());
+                };
+                state.revoked.store(true, Ordering::Release);
+                entry.tokens.clear();
+                state
+            };
+            loop {
+                let notified = state.notify.notified();
+                tokio::pin!(notified);
+                notified.as_mut().enable();
+                if state.running.load(Ordering::Acquire) == 0 {
+                    break;
+                }
+                notified.await;
+            }
+            self.snapshot_leases.lock().await.entries.remove(&key);
+            return Ok(());
+        }
        let opts = {
            let mut registry = self.snapshot_leases.lock().await;
            let Some(entry) = registry.entries.get_mut(&key) else {
@@ -9840,6 +10043,12 @@ impl DiskAPI for LocalDisk {
        opts: &ReadOptions,
    ) -> Result<FileInfo> {
        crate::hp_guard!("LocalDisk::read_version");
+        let stage_metrics_enabled = rustfs_io_metrics::get_stage_metrics_enabled();
+        let metrics_path = if stage_metrics_enabled && crate::bucket::utils::is_meta_bucketname(volume) {
+            GET_OBJECT_PATH_INTERNAL_META
+        } else {
+            GET_OBJECT_PATH_LEGACY_DUPLEX
+        };
        if !org_volume.is_empty() {
            let org_volume_path = self.io_get_bucket_path(org_volume)?;
            if !skip_access_checks(org_volume) {
@@ -9849,37 +10058,46 @@ impl DiskAPI for LocalDisk {
            }
        }

+        let path_resolve_start = get_stage_timer_if_enabled(stage_metrics_enabled);
        let file_path = self.io_get_object_path(volume, path)?;
        let volume_dir = self.io_get_bucket_path(volume)?;
+        record_get_stage_duration_if_enabled(metrics_path, GET_STAGE_READ_VERSION_PATH_RESOLVE, path_resolve_start);

+        let path_check_start = get_stage_timer_if_enabled(stage_metrics_enabled);
        check_path_length(file_path.to_string_lossy().as_ref())?;
+        record_get_stage_duration_if_enabled(metrics_path, GET_STAGE_READ_VERSION_PATH_CHECK, path_check_start);

        let read_data = opts.read_data;

-        let (data, _) = self
-            .read_raw(volume, volume_dir.clone(), file_path, read_data)
-            .await
-            .map_err(|e| {
-                if e == DiskError::FileNotFound && !version_id.is_empty() {
-                    DiskError::FileVersionNotFound
-                } else {
-                    e
-                }
-            })?;
+        let xlmeta_read_start = get_stage_timer_if_enabled(stage_metrics_enabled);
+        let raw_read_result = self.read_raw(volume, volume_dir.clone(), file_path, read_data).await;
+        record_get_stage_duration_if_enabled(metrics_path, GET_STAGE_READ_VERSION_XLMETA_READ, xlmeta_read_start);
+        let (data, _) = raw_read_result.map_err(|e| {
+            if e == DiskError::FileNotFound && !version_id.is_empty() {
+                DiskError::FileVersionNotFound
+            } else {
+                e
+            }
+        })?;

-        let mut fi = get_file_info(
-            &data,
-            volume,
-            path,
-            version_id,
-            FileInfoOpts {
-                data: read_data,
-                include_free_versions: opts.incl_free_versions,
-                include_part_checksums: false,
-            },
-        )?;
-
-        fi.validate_for_metadata_read()?;
+        let decode_start = get_stage_timer_if_enabled(stage_metrics_enabled);
+        let file_info_result: Result<FileInfo> = (|| {
+            let fi = get_file_info(
+                &data,
+                volume,
+                path,
+                version_id,
+                FileInfoOpts {
+                    data: read_data,
+                    include_free_versions: opts.incl_free_versions,
+                    include_part_checksums: false,
+                },
+            )?;
+            fi.validate_for_metadata_read()?;
+            Ok(fi)
+        })();
+        record_get_stage_duration_if_enabled(metrics_path, GET_STAGE_READ_VERSION_DECODE, decode_start);
+        let mut fi = file_info_result?;
        if fi.is_canonical_delete_marker() {
            return Ok(fi);
        }
@@ -10433,6 +10651,19 @@ impl DiskAPI for LocalDisk {
    }
 }

+impl LocalDisk {
+    pub(crate) async fn rename_data_borrowed(
+        &self,
+        src_volume: &str,
+        src_path: &str,
+        fi: &FileInfo,
+        dst_volume: &str,
+        dst_path: &str,
+    ) -> Result<RenameDataResp> {
+        <Self as DiskAPI>::rename_data(self, src_volume, src_path, fi.clone(), dst_volume, dst_path).await
+    }
+}
+
 async fn wait_for_startup_cleanup_signal(
    startup_cleanup_ready: &AtomicU32,
    startup_cleanup_notify: &Notify,
@@ -10562,6 +10793,108 @@ mod test {
        meta.marshal_msg().expect("test metadata should encode")
    }

+    #[test]
+    #[serial_test::serial]
+    fn read_version_records_local_metadata_stage_breakdown() {
+        let runtime = tokio::runtime::Builder::new_current_thread()
+            .enable_all()
+            .build()
+            .expect("test runtime should be created");
+        let recorder = crate::test_metrics::CapturingRecorder::default();
+        let previous_gate = rustfs_io_metrics::get_stage_metrics_enabled();
+        rustfs_io_metrics::set_get_stage_metrics_enabled(true);
+
+        metrics::with_local_recorder(&recorder, || {
+            runtime.block_on(async {
+                let dir = tempfile::tempdir().expect("temp dir should be created");
+                let endpoint =
+                    Endpoint::try_from(dir.path().to_str().expect("temp dir should be utf8")).expect("endpoint should parse");
+                let disk = LocalDisk::new(&endpoint, false).await.expect("local disk should be created");
+                let bucket = "bucket";
+                let object = "stage-breakdown";
+                ensure_test_volume(&disk, bucket).await;
+
+                let object_dir = dir.path().join(bucket).join(object);
+                fs::create_dir_all(&object_dir)
+                    .await
+                    .expect("object directory should be created");
+                fs::write(
+                    object_dir.join(STORAGE_FORMAT_FILE),
+                    test_meta(test_file_info(object, Uuid::new_v4(), None, Some(Bytes::from_static(b"inline")))),
+                )
+                .await
+                .expect("object metadata should be written");
+
+                disk.read_version(
+                    "",
+                    bucket,
+                    object,
+                    "",
+                    &ReadOptions {
+                        read_data: true,
+                        ..Default::default()
+                    },
+                )
+                .await
+                .expect("read_version should succeed");
+
+                let meta_object = "stage-breakdown-meta";
+                let meta_object_dir = dir.path().join(RUSTFS_META_BUCKET).join(meta_object);
+                fs::create_dir_all(&meta_object_dir)
+                    .await
+                    .expect("internal metadata object directory should be created");
+                fs::write(
+                    meta_object_dir.join(STORAGE_FORMAT_FILE),
+                    test_meta(test_file_info(meta_object, Uuid::new_v4(), None, Some(Bytes::from_static(b"meta")))),
+                )
+                .await
+                .expect("internal metadata should be written");
+
+                disk.read_version(
+                    "",
+                    RUSTFS_META_BUCKET,
+                    meta_object,
+                    "",
+                    &ReadOptions {
+                        read_data: true,
+                        ..Default::default()
+                    },
+                )
+                .await
+                .expect("internal metadata read_version should succeed");
+            });
+        });
+        rustfs_io_metrics::set_get_stage_metrics_enabled(previous_gate);
+
+        for stage in [
+            GET_STAGE_READ_VERSION_PATH_RESOLVE,
+            GET_STAGE_READ_VERSION_PATH_CHECK,
+            GET_STAGE_READ_VERSION_XLMETA_READ,
+            GET_STAGE_READ_VERSION_DECODE,
+        ] {
+            assert_eq!(
+                recorder
+                    .histogram_values(
+                        "rustfs_io_get_object_stage_duration_seconds",
+                        &[("path", GET_OBJECT_PATH_LEGACY_DUPLEX), ("stage", stage)]
+                    )
+                    .len(),
+                1,
+                "{stage} should be recorded once for user-bucket LocalDisk::read_version"
+            );
+            assert_eq!(
+                recorder
+                    .histogram_values(
+                        "rustfs_io_get_object_stage_duration_seconds",
+                        &[("path", GET_OBJECT_PATH_INTERNAL_META), ("stage", stage)]
+                    )
+                    .len(),
+                1,
+                "{stage} should be recorded once for internal-meta LocalDisk::read_version"
+            );
+        }
+    }
+
    #[test]
    fn inline_metadata_rollback_dir_avoids_real_data_dir_collision() {
        let target_version = Uuid::parse_str("11111111-2222-3333-4444-555555555555").expect("version id should parse");
@@ -12885,7 +13218,7 @@ mod test {
        let replacement_staging_parent_for_hook = replacement_staging_parent.clone();
        let staged_metadata_for_hook = staged_metadata.clone();
        let replacement_staged_metadata_for_hook = replacement_staged_metadata.clone();
-        set_rename_data_after_first_publication(object, move || {
+        set_rename_data_after_first_publication(&disk.root, bucket, object, move || {
            std::fs::rename(&object_dir_for_hook, &replacement_dir_for_hook)
                .expect_err("the destination object identity must remain pinned until xl.meta commits");
            std::fs::rename(&staging_parent_for_hook, &replacement_staging_parent_for_hook)
@@ -13152,7 +13485,7 @@ mod test {
        let replacement_dir_for_hook = replacement_dir.clone();
        let staged_metadata_for_hook = staged_metadata.clone();
        let replacement_staged_metadata_for_hook = replacement_staged_metadata.clone();
-        set_rename_data_after_first_publication(object, move || {
+        set_rename_data_after_first_publication(&disk.root, bucket, object, move || {
            std::fs::rename(&object_dir_for_hook, &replacement_dir_for_hook)
                .expect_err("the destination object identity must remain pinned after publishing its rollback backup");
            std::fs::rename(&staged_metadata_for_hook, &replacement_staged_metadata_for_hook)
@@ -13518,7 +13851,7 @@ mod test {

        let (entered_tx, entered_rx) = mpsc::channel();
        let (release_tx, release_rx) = mpsc::channel();
-        set_rename_data_after_first_publication(object, move || {
+        set_rename_data_after_first_publication(&disk.root, bucket, object, move || {
            entered_tx.send(()).expect("signal first publication");
            release_rx.recv().expect("wait while delete_volume is blocked");
        });
@@ -14112,7 +14445,7 @@ mod test {

        let (published_tx, published_rx) = mpsc::channel();
        let (release_tx, release_rx) = mpsc::channel();
-        set_rename_data_after_first_publication(object, move || {
+        set_rename_data_after_first_publication(&disk.root, bucket, object, move || {
            published_tx.send(()).expect("signal backup publication");
            release_rx.recv().expect("wait for lock-order assertion");
        });
@@ -18767,6 +19100,48 @@ mod test {
        assert!(matches!(disk.read_all(volume, &first_part).await, Err(DiskError::FileNotFound)));
    }

+    #[tokio::test]
+    async fn quota_mutation_fence_revoke_waits_for_active_claim_and_rejects_late_claims() {
+        use tempfile::tempdir;
+
+        let root_dir = tempdir().expect("temp dir should be created");
+        let endpoint = Endpoint::try_from(root_dir.path().to_string_lossy().as_ref()).expect("endpoint should parse");
+        let disk = Arc::new(LocalDisk::new(&endpoint, false).await.expect("local disk should be created"));
+        let bucket = "quota-fence-volume";
+        let object = "object";
+        let fence_path = quota_mutation_fence_path(bucket, object);
+        let token = disk
+            .acquire_snapshot_lease(RUSTFS_META_BUCKET, &fence_path)
+            .await
+            .expect("quota mutation token should be prepared");
+        let claim = disk
+            .claim_quota_mutation_fence(bucket, object, token)
+            .await
+            .expect("prepared token should be claimable");
+
+        let release_disk = Arc::clone(&disk);
+        let mut release = tokio::spawn(async move {
+            release_disk
+                .release_snapshot_lease(RUSTFS_META_BUCKET, &fence_path, SnapshotLeaseToken::revoke_all())
+                .await
+        });
+        assert!(
+            tokio::time::timeout(Duration::from_millis(50), &mut release).await.is_err(),
+            "revoke must wait until an already claimed mutation has finished"
+        );
+
+        drop(claim);
+        tokio::time::timeout(Duration::from_secs(1), release)
+            .await
+            .expect("revoke should wake after the final claim drops")
+            .expect("revoke task should not panic")
+            .expect("revoke should succeed");
+        assert!(matches!(
+            disk.claim_quota_mutation_fence(bucket, object, token).await,
+            Err(DiskError::FileNotFound)
+        ));
+    }
+
    #[tokio::test]
    async fn delete_version_keeps_later_part_until_snapshot_release() {
        use tempfile::tempdir;
@@ -13,7 +13,6 @@
 // limitations under the License.

 // #730: disk abstractions still carry staged health and direct-I/O migration paths.
-#![allow(dead_code)]

 pub mod disk_store;
 pub mod endpoint;
@@ -55,6 +54,7 @@ pub fn part_transaction_path(part_path: &str) -> String {

 use crate::cluster::rpc::RemoteDisk;
 use crate::cluster::rpc::build_internode_data_transport_from_env;
+use crate::disk::disk_store::DiskStoreRenameDataExt;
 use crate::disk::disk_store::LocalDiskWrapper;
 use crate::disk::health_state::RuntimeDriveHealthState;
 use crate::disk::local::ScanGuard;
@@ -72,6 +72,28 @@ use time::OffsetDateTime;
 use tokio::io::{AsyncRead, AsyncWrite};
 use uuid::Uuid;

+const QUOTA_MUTATION_FENCE_PREFIX: &str = "tmp/quota-mutation-fences/";
+pub(crate) const QUOTA_MUTATION_FENCE_METADATA_SUFFIX: &str = "quota-mutation-fence-token";
+
+pub(crate) fn quota_mutation_fence_path(bucket: &str, object: &str) -> String {
+    use sha2::{Digest, Sha256};
+
+    let mut input = Vec::with_capacity(bucket.len() + object.len() + 1);
+    input.extend_from_slice(bucket.as_bytes());
+    input.push(0);
+    input.extend_from_slice(object.as_bytes());
+    let digest = Sha256::digest(input);
+    format!(
+        "{QUOTA_MUTATION_FENCE_PREFIX}{}",
+        hex_simd::encode_to_string(digest, hex_simd::AsciiCase::Lower)
+    )
+}
+
+pub(crate) fn is_quota_mutation_fence_path(path: &str) -> bool {
+    path.strip_prefix(QUOTA_MUTATION_FENCE_PREFIX)
+        .is_some_and(|digest| digest.len() == 64 && digest.bytes().all(|byte| byte.is_ascii_hexdigit()))
+}
+
 pub type DiskStore = Arc<Disk>;

 pub type FileReader = Box<dyn AsyncRead + Send + Sync + Unpin>;
@@ -96,6 +118,20 @@ impl SnapshotLeaseToken {
    pub fn as_bytes(&self) -> &[u8; 16] {
        self.0.as_bytes()
    }
+
+    pub(crate) fn as_uuid(self) -> Uuid {
+        self.0
+    }
+
+    #[doc(hidden)]
+    pub fn revoke_all() -> Self {
+        Self(Uuid::nil())
+    }
+
+    #[doc(hidden)]
+    pub fn is_revoke_all(self) -> bool {
+        self.0.is_nil()
+    }
 }

 impl Default for SnapshotLeaseToken {
@@ -398,10 +434,8 @@ impl DiskAPI for Disk {
        dst_volume: &str,
        dst_path: &str,
    ) -> Result<RenameDataResp> {
-        match self {
-            Disk::Local(local_disk) => local_disk.rename_data(src_volume, src_path, fi, dst_volume, dst_path).await,
-            Disk::Remote(remote_disk) => remote_disk.rename_data(src_volume, src_path, fi, dst_volume, dst_path).await,
-        }
+        self.rename_data_borrowed(src_volume, src_path, &fi, dst_volume, dst_path)
+            .await
    }

    #[tracing::instrument(level = "trace", skip_all)]
@@ -631,6 +665,30 @@ impl DiskAPI for Disk {
    }
 }

+impl Disk {
+    pub(crate) async fn rename_data_borrowed(
+        &self,
+        src_volume: &str,
+        src_path: &str,
+        fi: &FileInfo,
+        dst_volume: &str,
+        dst_path: &str,
+    ) -> Result<RenameDataResp> {
+        match self {
+            Disk::Local(local_disk) => {
+                local_disk
+                    .rename_data_borrowed(src_volume, src_path, fi, dst_volume, dst_path)
+                    .await
+            }
+            Disk::Remote(remote_disk) => {
+                remote_disk
+                    .rename_data_borrowed(src_volume, src_path, fi, dst_volume, dst_path)
+                    .await
+            }
+        }
+    }
+}
+
 impl Disk {
    pub async fn ns_scanner_server_epoch(&self) -> Result<Option<Uuid>> {
        match self {
@@ -1055,6 +1113,10 @@ pub struct DiskInfo {
 }

 #[derive(Clone, Debug, Default)]
+#[allow(
+    dead_code,
+    reason = "MinIO-parity disk info shape with no constructor in this port (backlog#1823)"
+)]
 pub struct Info {
    pub total: u64,
    pub free: u64,
@@ -1313,6 +1375,7 @@ pub fn conv_part_err_to_int(err: &Option<Error>) -> usize {
    }
 }

+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 pub fn has_part_err(part_errs: &[usize]) -> bool {
    part_errs.iter().any(|err| *err != CHECK_PART_SUCCESS)
 }
@@ -306,12 +306,20 @@ fn disk_namespace_mutation_lock(path: &Path) -> Arc<NamespaceMutationLock> {
 pub(crate) struct NamespaceMutationLease {
    _namespace_guard: OwnedMutexGuard<()>,
    _volume_guard: Option<OwnedRwLockReadGuard<()>>,
+    external_guard: Mutex<Option<Arc<dyn Send + Sync>>>,
+}
+
+impl NamespaceMutationLease {
+    pub(crate) fn attach_external_guard(&self, guard: Arc<dyn Send + Sync>) {
+        *self.external_guard.lock() = Some(guard);
+    }
 }

 async fn acquire_namespace_mutation_lease(path: &Path) -> Arc<NamespaceMutationLease> {
    Arc::new(NamespaceMutationLease {
        _namespace_guard: disk_namespace_mutation_lock(path).lock_owned().await,
        _volume_guard: None,
+        external_guard: Mutex::new(None),
    })
 }

@@ -327,6 +335,7 @@ pub(crate) async fn acquire_rename_data_mutation_lease(
    Arc::new(NamespaceMutationLease {
        _namespace_guard: namespace_guard,
        _volume_guard: Some(volume_guard),
+        external_guard: Mutex::new(None),
    })
 }

@@ -562,6 +571,10 @@ fn regular_files(dir: &Path) -> io::Result<Vec<PathBuf>> {

 /// Fdatasync every regular file directly inside `dir`, then fsync the directory
 /// itself.
+#[allow(
+    dead_code,
+    reason = "reached only through sync_dir_files, whose callers are tests (backlog#1823)"
+)]
 pub fn sync_dir_files_std(dir: impl AsRef<Path>) -> io::Result<()> {
    for entry in std::fs::read_dir(dir.as_ref())? {
        let entry = entry?;
@@ -574,6 +587,7 @@ pub fn sync_dir_files_std(dir: impl AsRef<Path>) -> io::Result<()> {

 /// Async wrapper around [`sync_dir_files_std`]. Large directories flush files
 /// concurrently, bounded both per directory and process-wide.
+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 pub async fn sync_dir_files(dir: impl AsRef<Path>) -> io::Result<()> {
    sync_dir_files_with_limiter(dir, Arc::new(Semaphore::new(MAX_PARALLEL_FILE_SYNCS))).await
 }
@@ -1800,10 +1814,6 @@ impl RenameCommitGuard {
        })
    }

-    pub(crate) fn lock_destination_directory_for_path_access(&self, directory: &Path) -> io::Result<RenameDestinationPathGuard> {
-        self.destination_directory_guard(directory, false)
-    }
-
    pub(crate) fn create_destination_directory_for_path_access(
        &self,
        directory: &Path,
@@ -2849,13 +2859,6 @@ pub async fn os_mkdir_all(dir_path: impl AsRef<Path>, base_dir: impl AsRef<Path>
    Ok(())
 }

-/// Check if a file exists.
-/// Returns true if the file exists, false otherwise.
-#[tracing::instrument(level = "debug", skip_all)]
-pub fn file_exists(path: impl AsRef<Path>) -> bool {
-    std::fs::metadata(path.as_ref()).map(|_| true).unwrap_or(false)
-}
-
 /// Whether an [`io::Error`] means "the directory is not empty".
 ///
 /// POSIX lets `rmdir`/`rename` report a non-empty directory as either
@@ -26,6 +26,7 @@ pub(crate) const GET_RECONSTRUCT_OUTCOME_SKIP_DATA_COMPLETE: &str = "skip_data_c
 pub(crate) const GET_RECONSTRUCT_OUTCOME_SKIP_EMPTY_PAYLOAD: &str = "skip_empty_payload";

 pub(crate) trait DecodeWorkspace: Send + Sync + 'static {
+    #[allow(dead_code, reason = "workspace width asserted by decode_reader tests (backlog#1823)")]
    fn shard_len(&self) -> usize;
 }

@@ -33,11 +34,14 @@ pub(crate) trait ErasureDecodeEngine: Send + Sync + 'static {
    type Workspace: DecodeWorkspace;

    fn data_shards(&self) -> usize;
+    #[allow(dead_code, reason = "engine trait facet asserted by decode_reader tests (backlog#1823)")]
    fn parity_shards(&self) -> usize;
    fn block_size(&self) -> usize;
    fn engine_name(&self) -> &'static str;

+    #[allow(dead_code, reason = "engine trait facet asserted by decode_reader tests (backlog#1823)")]
    fn supports_progressive_decode(&self) -> bool;
+    #[allow(dead_code, reason = "engine trait facet asserted by decode_reader tests (backlog#1823)")]
    fn supports_aligned_shards(&self) -> bool;

    fn prepare_workspace(&self, shard_len: usize) -> io::Result<Self::Workspace>;
@@ -24,6 +24,7 @@ impl RustfsCodecDecodeWorkspace {
    }

    #[inline]
+    #[allow(dead_code, reason = "workspace width asserted by decode_reader tests (backlog#1823)")]
    pub(crate) fn shard_len(&self) -> usize {
        self.shard_len
    }
@@ -213,6 +213,7 @@ fn shard_read_launch_rank(cost: ShardReadCost) -> u8 {
    }
 }

+#[allow(dead_code, reason = "launch ordering asserted by this file's tests (backlog#1823)")]
 fn shard_read_launch_order(read_costs: &[ShardReadCost], num_readers: usize, locality_preference_enabled: bool) -> Vec<usize> {
    let mut order: Vec<usize> = (0..num_readers).collect();
    if locality_preference_enabled {
@@ -408,6 +409,10 @@ where
    R: crate::erasure::coding::ShardSource,
 {
    // Readers should handle disk errors before being passed in, ensuring each reader reaches the available number of BitrotReaders
+    #[allow(
+        dead_code,
+        reason = "ParallelReader constructor used only by this file's tests (backlog#1823)"
+    )]
    pub fn new(readers: Vec<Option<BitrotReader<R>>>, e: Erasure, offset: usize, total_length: usize) -> Self {
        Self::new_with_metrics_path_read_timeout_and_reconstruction_verification(
            readers,
@@ -420,6 +425,7 @@ where
        )
    }

+    #[allow(dead_code, reason = "constructor used only by this file's tests (backlog#1823)")]
    pub fn new_with_metrics_path(
        readers: Vec<Option<BitrotReader<R>>>,
        e: Erasure,
@@ -438,6 +444,7 @@ where
        )
    }

+    #[allow(dead_code, reason = "constructor used only by this file's tests (backlog#1823)")]
    pub fn new_with_metrics_path_and_read_costs(
        readers: Vec<Option<BitrotReader<R>>>,
        e: Erasure,
@@ -514,6 +521,7 @@ where
        )
    }

+    #[allow(dead_code, reason = "constructor used only by this file's tests (backlog#1823)")]
    fn new_with_read_timeout(
        readers: Vec<Option<BitrotReader<R>>>,
        e: Erasure,
@@ -1330,10 +1338,6 @@ where
            }
        }
    }
-
-    pub fn can_decode(&self, shards: &[Option<Vec<u8>>]) -> bool {
-        shards.iter().filter(|s| s.is_some()).count() >= self.data_shards
-    }
 }

 #[async_trait::async_trait]
@@ -1539,6 +1543,7 @@ impl Erasure {
            .await
    }

+    #[allow(dead_code, reason = "read-cost decode path asserted by this file's tests (backlog#1823)")]
    pub(crate) async fn decode_with_read_costs<W, R>(
        &self,
        writer: &mut W,
@@ -1609,9 +1614,9 @@ impl Erasure {
            *ret_err = Some(err.into());
        }

-        // Equivalent to `ParallelReader::can_decode`; inlined so this helper does
-        // not need to borrow the reader, leaving the reader free for the
-        // concurrent next-stripe read under prefetch.
+        // Shard-availability check, written out here rather than called on the
+        // reader so this helper does not need to borrow it, leaving the reader
+        // free for the concurrent next-stripe read under prefetch.
        let available_shards = shards.iter().filter(|shard| shard.is_some()).count();
        if available_shards < self.data_shards {
            let reason = GetObjectFailureReason::ReadQuorum;
@@ -138,6 +138,10 @@ where
    S: ShardStripeSource + Send + 'static,
    E: ErasureDecodeEngine + Clone + Send + Sync + 'static,
 {
+    #[allow(
+        dead_code,
+        reason = "default-metrics-path constructor used only by this file's tests (backlog#1823)"
+    )]
    pub(crate) fn new(source: S, engine: E, total_length: usize) -> io::Result<Self> {
        Self::new_with_metrics_path(source, engine, total_length, GET_OBJECT_PATH_CODEC_STREAMING)
    }
@@ -679,6 +683,10 @@ pub(crate) struct SyncErasureDecodeReader<R> {
 }

 impl<R> SyncErasureDecodeReader<R> {
+    #[allow(
+        dead_code,
+        reason = "default-metrics-path constructor used only by this file's tests (backlog#1823)"
+    )]
    pub(crate) fn new(inner: R) -> Self {
        Self::new_with_metrics_path(inner, GET_OBJECT_PATH_CODEC_STREAMING)
    }
@@ -805,6 +813,7 @@ where
    Ok(true)
 }

+#[allow(dead_code, reason = "shard emission asserted by this file's tests (backlog#1823)")]
 fn emit_data_shards(state: &StripeReadState, data_shards: usize, block_size: usize, remaining: usize) -> io::Result<Vec<u8>> {
    let mut output = Vec::new();
    emit_data_shards_into(state, data_shards, block_size, remaining, &mut output)?;
@@ -166,6 +166,7 @@ where
    if total == 0 { Ok(None) } else { Ok(Some(total)) }
 }

+#[allow(dead_code, reason = "byte accounting asserted by this file's tests (backlog#1823)")]
 fn queued_block_bytes(block: &[Bytes]) -> usize {
    block.iter().map(Bytes::len).sum()
 }
@@ -71,10 +71,16 @@ impl EncodedBlock {

 const MODERN_MAX_TOTAL_SHARDS: usize = <reed_solomon_erasure::galois_8::Field as reed_solomon_erasure::Field>::ORDER;
 const MODERN_REED_SOLOMON_CACHE_MAX_ENTRIES: usize = 64;
+const LEGACY_REED_SOLOMON_CACHE_MAX_ENTRIES: usize = 16;
+// Vec growth may retain twice the requested logical length. Keeping the logical
+// workspace at half the budget bounds each cached workspace's shard allocation to 1 MiB.
+const LEGACY_REED_SOLOMON_CACHE_MAX_LOGICAL_SHARD_BYTES_PER_WORKSPACE: usize = 512 * 1024;

 type ModernReedSolomonCache = RwLock<HashMap<(usize, usize), Arc<ReedSolomon>>>;
+type LegacyReedSolomonCache = RwLock<HashMap<(usize, usize), Arc<LegacyReedSolomonEncoder>>>;

 static MODERN_REED_SOLOMON_CACHE: OnceLock<ModernReedSolomonCache> = OnceLock::new();
+static LEGACY_REED_SOLOMON_CACHE: OnceLock<LegacyReedSolomonCache> = OnceLock::new();

 /// Errors returned when constructing an [`Erasure`] codec.
 #[derive(Debug, thiserror::Error)]
@@ -141,43 +147,61 @@ pub fn calc_shard_size_legacy(block_size: usize, data_shards: usize) -> usize {
 struct LegacyReedSolomonEncoder {
    data_shards: usize,
    parity_shards: usize,
-    encoder_cache: std::sync::RwLock<Option<reed_solomon_simd::ReedSolomonEncoder>>,
-    decoder_cache: std::sync::RwLock<Option<reed_solomon_simd::ReedSolomonDecoder>>,
-}
-
-impl Clone for LegacyReedSolomonEncoder {
-    fn clone(&self) -> Self {
-        Self {
-            data_shards: self.data_shards,
-            parity_shards: self.parity_shards,
-            encoder_cache: std::sync::RwLock::new(None),
-            decoder_cache: std::sync::RwLock::new(None),
-        }
-    }
+    cache_workspaces: bool,
+    encoder_cache: RwLock<Option<reed_solomon_simd::ReedSolomonEncoder>>,
+    decoder_cache: RwLock<Option<reed_solomon_simd::ReedSolomonDecoder>>,
 }

 impl LegacyReedSolomonEncoder {
-    fn new(_data_shards: usize, _parity_shards: usize) -> io::Result<Self> {
+    fn new(data_shards: usize, parity_shards: usize) -> io::Result<Self> {
+        Self::with_workspace_cache(data_shards, parity_shards, false)
+    }
+
+    fn with_workspace_cache(data_shards: usize, parity_shards: usize, cache_workspaces: bool) -> io::Result<Self> {
        Ok(Self {
-            data_shards: _data_shards,
-            parity_shards: _parity_shards,
-            encoder_cache: std::sync::RwLock::new(None),
-            decoder_cache: std::sync::RwLock::new(None),
+            data_shards,
+            parity_shards,
+            cache_workspaces,
+            encoder_cache: RwLock::new(None),
+            decoder_cache: RwLock::new(None),
        })
    }

+    fn logical_shard_bytes_upper_bound(&self, shard_len: usize) -> Option<usize> {
+        let aligned_shard_len = shard_len.checked_add(63)?.checked_div(64)?.checked_mul(64)?;
+        let high_rate_decoder_work_count = self
+            .parity_shards
+            .checked_next_power_of_two()?
+            .checked_add(self.data_shards)?
+            .checked_next_power_of_two()?;
+        let low_rate_decoder_work_count = self
+            .data_shards
+            .checked_next_power_of_two()?
+            .checked_add(self.parity_shards)?
+            .checked_next_power_of_two()?;
+        aligned_shard_len.checked_mul(high_rate_decoder_work_count.max(low_rate_decoder_work_count))
+    }
+
+    fn should_cache_workspace(&self, shard_len: usize) -> bool {
+        self.cache_workspaces
+            && self
+                .logical_shard_bytes_upper_bound(shard_len)
+                .is_some_and(|bytes| bytes <= LEGACY_REED_SOLOMON_CACHE_MAX_LOGICAL_SHARD_BYTES_PER_WORKSPACE)
+    }
+
    fn encode(&self, shards: SmallVec<[&mut [u8]; 16]>) -> io::Result<()> {
        let mut shards_vec: Vec<&mut [u8]> = shards.into_vec();
        if shards_vec.is_empty() {
            return Ok(());
        }
        let shard_len = shards_vec[0].len();
+        let cached_encoder = self
+            .encoder_cache
+            .write()
+            .map_err(|_| io::Error::other("Failed to acquire encoder cache lock"))?
+            .take();
        let mut encoder = {
-            let mut cache_guard = self
-                .encoder_cache
-                .write()
-                .map_err(|_| io::Error::other("Failed to acquire encoder cache lock"))?;
-            match cache_guard.take() {
+            match cached_encoder {
                Some(mut cached) => {
                    if cached.reset(self.data_shards, self.parity_shards, shard_len).is_err() {
                        reed_solomon_simd::ReedSolomonEncoder::new(self.data_shards, self.parity_shards, shard_len)
@@ -204,10 +228,15 @@ impl LegacyReedSolomonEncoder {
            }
        }
        drop(result);
-        *self
-            .encoder_cache
-            .write()
-            .map_err(|_| io::Error::other("Failed to return encoder to cache"))? = Some(encoder);
+        if self.should_cache_workspace(shard_len) {
+            let mut cache = self
+                .encoder_cache
+                .write()
+                .map_err(|_| io::Error::other("Failed to return encoder to cache"))?;
+            if cache.is_none() {
+                *cache = Some(encoder);
+            }
+        }
        Ok(())
    }

@@ -221,13 +250,13 @@ impl LegacyReedSolomonEncoder {
            .find_map(|s| s.as_ref().map(|v| v.len()))
            .ok_or_else(|| io::Error::other("No valid shards found for reconstruction"))?;

+        let cached_decoder = self
+            .decoder_cache
+            .write()
+            .map_err(|_| io::Error::other("Failed to acquire decoder cache lock"))?
+            .take();
        let mut decoder = {
-            let mut cache_guard = self
-                .decoder_cache
-                .write()
-                .map_err(|_| io::Error::other("Failed to acquire decoder cache lock"))?;
-
-            match cache_guard.take() {
+            match cached_decoder {
                Some(mut cached_decoder) => {
                    if let Err(e) = cached_decoder.reset(self.data_shards, self.parity_shards, shard_len) {
                        warn!("Failed to reset SIMD decoder: {:?}, creating new one", e);
@@ -274,10 +303,15 @@ impl LegacyReedSolomonEncoder {

        drop(result);

-        *self
-            .decoder_cache
-            .write()
-            .map_err(|_| io::Error::other("Failed to return decoder to cache"))? = Some(decoder);
+        if self.should_cache_workspace(shard_len) {
+            let mut cache = self
+                .decoder_cache
+                .write()
+                .map_err(|_| io::Error::other("Failed to return decoder to cache"))?;
+            if cache.is_none() {
+                *cache = Some(decoder);
+            }
+        }

        Ok(())
    }
@@ -435,6 +469,39 @@ fn cached_modern_reed_solomon(data_shards: usize, parity_shards: usize) -> Resul
    Ok(encoder)
 }

+fn cached_legacy_reed_solomon(data_shards: usize, parity_shards: usize) -> io::Result<Arc<LegacyReedSolomonEncoder>> {
+    let cache = LEGACY_REED_SOLOMON_CACHE.get_or_init(|| RwLock::new(HashMap::new()));
+    cached_legacy_reed_solomon_in(cache, data_shards, parity_shards)
+}
+
+fn cached_legacy_reed_solomon_in(
+    cache: &LegacyReedSolomonCache,
+    data_shards: usize,
+    parity_shards: usize,
+) -> io::Result<Arc<LegacyReedSolomonEncoder>> {
+    let key = (data_shards, parity_shards);
+    if let Some(encoder) = cache
+        .read()
+        .unwrap_or_else(|poisoned| poisoned.into_inner())
+        .get(&key)
+        .cloned()
+    {
+        return Ok(encoder);
+    }
+
+    let mut cache = cache.write().unwrap_or_else(|poisoned| poisoned.into_inner());
+    if let Some(existing) = cache.get(&key) {
+        return Ok(Arc::clone(existing));
+    }
+    if cache.len() < LEGACY_REED_SOLOMON_CACHE_MAX_ENTRIES {
+        let encoder = Arc::new(LegacyReedSolomonEncoder::with_workspace_cache(data_shards, parity_shards, true)?);
+        cache.insert(key, Arc::clone(&encoder));
+        return Ok(encoder);
+    }
+    drop(cache);
+    Ok(Arc::new(LegacyReedSolomonEncoder::new(data_shards, parity_shards)?))
+}
+
 fn encode_parity_shards<F>(shards: &mut [Option<Vec<u8>>], data_shards: usize, parity_shards: usize, encode: F) -> io::Result<()>
 where
    F: FnOnce(SmallVec<[&mut [u8]; 16]>) -> io::Result<()>,
@@ -551,7 +618,7 @@ pub struct Erasure {
    pub data_shards: usize,
    pub parity_shards: usize,
    encoder: Option<ReedSolomonEncoder>,
-    legacy_encoder: Option<LegacyReedSolomonEncoder>,
+    legacy_encoder: Option<Arc<LegacyReedSolomonEncoder>>,
    pub block_size: usize,
    uses_legacy: bool,
    _id: Uuid,
@@ -687,7 +754,7 @@ impl Erasure {

        let legacy_encoder = if uses_legacy && parity_shards > 0 {
            Some(
-                LegacyReedSolomonEncoder::new(data_shards, parity_shards)
+                cached_legacy_reed_solomon(data_shards, parity_shards)
                    .map_err(|source| ErasureConstructionError::LegacyEncoder { source })?,
            )
        } else {
@@ -1043,6 +1110,10 @@ impl Erasure {
    ///
    /// # Errors
    /// Returns error if reading from reader fails or if callback returns error
+    #[allow(
+        dead_code,
+        reason = "callback encode path exercised only by this file's tests (backlog#1823)"
+    )]
    pub(crate) async fn encode_stream_callback_async<F, Fut, E, R>(
        self: std::sync::Arc<Self>,
        reader: &mut R,
@@ -1405,7 +1476,7 @@ mod tests {
        assert_eq!(cloned.block_size, legacy.block_size);
        assert!(cloned.uses_legacy);

-        let data = b"legacy clone should keep independent SIMD caches";
+        let data = b"legacy clone should preserve SIMD codec behavior";
        let encoded = cloned.encode_data(data).expect("legacy clone should encode");
        let mut shards = optional_shards(&encoded);
        shards[0] = None;
@@ -1413,6 +1484,93 @@ mod tests {
        assert_eq!(recover_data(&shards, cloned.data_shards, data.len()), data);
    }

+    #[test]
+    fn legacy_codecs_share_process_cache_across_erasure_instances() {
+        let first = Erasure::new_with_options(6, 3, 64, true)
+            .legacy_encoder
+            .expect("legacy codec should be initialized");
+        let second = Erasure::new_with_options(6, 3, 128, true)
+            .legacy_encoder
+            .expect("same legacy shard layout should be initialized");
+
+        assert!(Arc::ptr_eq(&first, &second));
+    }
+
+    #[test]
+    fn legacy_workspace_cache_rejects_oversize_buffers_and_isolates_layouts() {
+        let four_plus_two = Erasure::new_with_options(4, 2, 64, true)
+            .legacy_encoder
+            .expect("legacy codec should be initialized");
+        let four_plus_one = Erasure::new_with_options(4, 1, 64, true)
+            .legacy_encoder
+            .expect("distinct parity layout should be initialized");
+        let three_plus_two = Erasure::new_with_options(3, 2, 64, true)
+            .legacy_encoder
+            .expect("distinct data layout should be initialized");
+
+        assert!(!Arc::ptr_eq(&four_plus_two, &four_plus_one));
+        assert!(!Arc::ptr_eq(&four_plus_two, &three_plus_two));
+        assert_eq!(four_plus_two.logical_shard_bytes_upper_bound(64 * 1024), Some(512 * 1024));
+        assert!(four_plus_two.should_cache_workspace(64 * 1024));
+        assert!(!four_plus_two.should_cache_workspace(64 * 1024 + 1));
+
+        let nine_plus_seven =
+            LegacyReedSolomonEncoder::with_workspace_cache(9, 7, true).expect("9+7 legacy codec should construct");
+        assert_eq!(nine_plus_seven.logical_shard_bytes_upper_bound(16 * 1024), Some(512 * 1024));
+        assert!(nine_plus_seven.should_cache_workspace(16 * 1024));
+        assert!(!nine_plus_seven.should_cache_workspace(16 * 1024 + 1));
+
+        let uncached = LegacyReedSolomonEncoder::new(4, 2).expect("uncached legacy codec should construct");
+        assert!(!uncached.should_cache_workspace(64));
+    }
+
+    #[test]
+    fn saturated_legacy_codec_cache_does_not_retain_more_workspaces() {
+        let cache = RwLock::new(HashMap::new());
+        for parity_shards in 1..=LEGACY_REED_SOLOMON_CACHE_MAX_ENTRIES {
+            let cached =
+                cached_legacy_reed_solomon_in(&cache, 32, parity_shards).expect("cacheable legacy codec should construct");
+            assert!(cached.cache_workspaces);
+        }
+
+        let uncached =
+            cached_legacy_reed_solomon_in(&cache, 31, 1).expect("uncached legacy codec should construct after saturation");
+        assert!(!uncached.cache_workspaces);
+        assert_eq!(
+            cache.read().expect("cache lock should remain healthy").len(),
+            LEGACY_REED_SOLOMON_CACHE_MAX_ENTRIES
+        );
+    }
+
+    #[test]
+    fn concurrent_legacy_codecs_preserve_byte_exact_results() {
+        let barrier = Arc::new(std::sync::Barrier::new(2));
+        let payloads = [vec![0x35; 257], vec![0xca; 1025]];
+
+        std::thread::scope(|scope| {
+            let handles = payloads.each_ref().map(|payload| {
+                let barrier = Arc::clone(&barrier);
+                scope.spawn(move || {
+                    let erasure = Erasure::new_with_options(6, 3, 2048, true);
+                    barrier.wait();
+                    let encoded = erasure.encode_data(payload).expect("concurrent legacy encode should succeed");
+                    barrier.wait();
+
+                    let mut shards = optional_shards(&encoded);
+                    shards[0] = None;
+                    erasure
+                        .decode_data(&mut shards)
+                        .expect("concurrent legacy decode should reconstruct the missing shard");
+                    recover_data(&shards, erasure.data_shards, payload.len())
+                })
+            });
+
+            for (handle, payload) in handles.into_iter().zip(payloads.iter()) {
+                assert_eq!(handle.join().expect("concurrent legacy codec worker should not panic"), *payload);
+            }
+        });
+    }
+
    #[test]
    fn legacy_verify_reports_invalid_empty_valid_and_corrupt_parity_sets() {
        let legacy = LegacyReedSolomonEncoder::new(2, 2).expect("legacy encoder should construct");
@@ -13,7 +13,6 @@
 // limitations under the License.

 // #730: erasure codec migration keeps staged streaming decode paths in this module.
-#![allow(dead_code)]

 pub(crate) mod codec;
 pub(crate) mod coding;
@@ -13,13 +13,12 @@
 // limitations under the License.

 // #730: error taxonomy still exposes compatibility variants while callers move to contracts.
-#![allow(dead_code)]

 use crate::bucket::error::BucketMetadataError;
 use crate::disk::error::DiskError;
 use crate::storage_api_contracts::{error::StorageErrorCode, range::HTTPRangeError};
 use rustfs_utils::path::decode_dir_object;
-use s3s::{S3Error, S3ErrorCode};
+use s3s::S3ErrorCode;

 pub type Error = StorageError;
 pub type Result<T> = core::result::Result<T, Error>;
@@ -902,6 +901,7 @@ pub fn is_err_decommission_running(err: &Error) -> bool {
    matches!(err, &StorageError::DecommissionAlreadyRunning)
 }

+#[allow(dead_code, reason = "predicate asserted by this file's tests (backlog#1823)")]
 pub fn is_err_rebalance_running(err: &Error) -> bool {
    matches!(err, &StorageError::RebalanceAlreadyRunning)
 }
@@ -910,14 +910,11 @@ pub fn is_err_operation_canceled(err: &Error) -> bool {
    matches!(err, &StorageError::OperationCanceled)
 }

+#[allow(dead_code, reason = "predicate asserted by this file's tests (backlog#1823)")]
 pub fn is_err_not_initialized(err: &Error) -> bool {
    err.to_string().contains("errServerNotInitialized") || err.to_string().contains("ServerNotInitialized")
 }

-pub fn is_err_io(err: &Error) -> bool {
-    matches!(err, &StorageError::Io(_))
-}
-
 /// Strict "not found" predicate that only matches genuine object/version/volume
 /// absence errors: `FileNotFound`/`VolumeNotFound`/`FileVersionNotFound`/
 /// `ObjectNotFound`/`VersionNotFound`.
@@ -1078,21 +1075,6 @@ pub struct GenericError {

 #[derive(Debug, thiserror::Error, PartialEq, Eq)]
 pub enum ObjectApiError {
-    #[error("Operation timed out")]
-    OperationTimedOut,
-
-    #[error("etag of the object has changed")]
-    InvalidETag,
-
-    #[error("BackendDown")]
-    BackendDown(String),
-
-    #[error("Unsupported headers in Metadata")]
-    UnsupportedMetadata,
-
-    #[error("Method not allowed: {}/{}", .0.bucket, .0.object)]
-    MethodNotAllowed(GenericError),
-
    #[error("The operation is not valid for the current state of the object {}/{}({})", .0.bucket, .0.object, .0.version_id)]
    InvalidObjectState(GenericError),
 }
@@ -1109,96 +1091,6 @@ pub struct ErrorResponse {
    pub host_id: String,
 }

-pub fn error_resp_to_object_err(err: ErrorResponse, params: Vec<&str>) -> std::io::Error {
-    let mut bucket = "";
-    let mut object = "";
-    let mut version_id = "";
-    if !params.is_empty() {
-        bucket = params[0];
-    }
-    if params.len() >= 2 {
-        object = params[1];
-    }
-    if params.len() >= 3 {
-        version_id = params[2];
-    }
-
-    if is_network_or_host_down(&err.to_string(), false) {
-        return std::io::Error::other(ObjectApiError::BackendDown(format!("{err}")));
-    }
-
-    let err_ = std::io::Error::other(err.to_string());
-    let r_err = err;
-    let err;
-    let bucket = bucket.to_string();
-    let object = object.to_string();
-    let version_id = version_id.to_string();
-
-    match r_err.code {
-        S3ErrorCode::BucketNotEmpty => {
-            err = std::io::Error::other(StorageError::BucketNotEmpty("".to_string()).to_string());
-        }
-        S3ErrorCode::InvalidBucketName => {
-            err = std::io::Error::other(StorageError::BucketNameInvalid(bucket));
-        }
-        S3ErrorCode::InvalidPart => {
-            err = std::io::Error::other(StorageError::InvalidPart(0, bucket, object /* , version_id */));
-        }
-        S3ErrorCode::NoSuchBucket => {
-            err = std::io::Error::other(StorageError::BucketNotFound(bucket));
-        }
-        S3ErrorCode::NoSuchKey => {
-            if !object.is_empty() {
-                err = std::io::Error::other(StorageError::ObjectNotFound(bucket, object));
-            } else {
-                err = std::io::Error::other(StorageError::BucketNotFound(bucket));
-            }
-        }
-        S3ErrorCode::NoSuchVersion => {
-            if !object.is_empty() {
-                err = std::io::Error::other(StorageError::ObjectNotFound(bucket, object)); //, version_id);
-            } else {
-                err = std::io::Error::other(StorageError::BucketNotFound(bucket));
-            }
-        }
-        S3ErrorCode::AccessDenied => {
-            err = std::io::Error::other(StorageError::PrefixAccessDenied(bucket, object));
-        }
-        S3ErrorCode::NoSuchUpload => {
-            err = std::io::Error::other(StorageError::InvalidUploadID(bucket, object, version_id));
-        }
-        _ => {
-            err = err_;
-        }
-    }
-
-    err
-}
-
-pub fn storage_to_object_err(err: Error, params: Vec<&str>) -> S3Error {
-    let storage_err = &err;
-    let mut bucket: String = "".to_string();
-    let mut object: String = "".to_string();
-    if !params.is_empty() {
-        bucket = params[0].to_string();
-    }
-    if params.len() >= 2 {
-        object = decode_dir_object(params[1]);
-    }
-    match storage_err {
-        StorageError::MethodNotAllowed => S3Error::with_message(
-            S3ErrorCode::MethodNotAllowed,
-            ObjectApiError::MethodNotAllowed(GenericError {
-                bucket,
-                object,
-                ..Default::default()
-            })
-            .to_string(),
-        ),
-        _ => s3s::S3Error::with_message(S3ErrorCode::Custom("err".into()), err.to_string()),
-    }
-}
-
 #[cfg(test)]
 mod tests {
    use super::*;
@@ -13,8 +13,6 @@
 // limitations under the License.

 // #730: event target types are retained for notification owner migration.
-#![allow(dead_code)]

 pub mod name;
-pub mod targetid;
 pub mod targetlist;
@@ -1,25 +0,0 @@
-#![allow(clippy::all)]
-// Copyright 2024 RustFS Team
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-pub struct TargetID {
-    id: String,
-    name: String,
-}
-
-impl TargetID {
-    fn to_string(&self) -> String {
-        format!("{}:{}", self.id, self.name)
-    }
-}
@@ -12,18 +12,20 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

-use crate::event::targetid::TargetID;
 use std::sync::atomic::AtomicI64;

+/// Placeholder notification target list held by `EventNotifier`.
+///
+/// The working notification stack lives in `rustfs-notify` / `rustfs-targets`;
+/// this type never grew past its counter. `total_events` is read by the
+/// notifier's log line but nothing increments it, so that field reports zero.
 #[derive(Default)]
+#[allow(
+    dead_code,
+    reason = "held only by the dead ecstore EventNotifier; see services/event_notification.rs (backlog#1823)"
+)]
 pub struct TargetList {
-    pub current_send_calls: AtomicI64,
    pub total_events: AtomicI64,
-    pub events_skipped: AtomicI64,
-    pub events_errors_total: AtomicI64,
-    //pub targets: HashMap<TargetID, Target>,
-    //pub queue:   AsyncEvent,
-    //pub targetStats: HashMap<TargetID, TargetStat>,
 }

 impl TargetList {
@@ -31,14 +33,3 @@ impl TargetList {
        TargetList::default()
    }
 }
-
-struct TargetStat {
-    current_send_calls: i64,
-    total_events: i64,
-    failed_events: i64,
-}
-
-struct TargetIDResult {
-    id: TargetID,
-    err: std::io::Error,
-}
@@ -704,6 +704,7 @@ pub(crate) async fn create_bitrot_reader_from_bytes_with_stage_metrics(
 }

 #[allow(clippy::too_many_arguments)]
+#[allow(dead_code, reason = "asserted by this file's tests (backlog#1823)")]
 pub fn create_deferred_bitrot_reader(
    inline_data: Option<Bytes>,
    disk: Option<DiskStore>,
--- a/Show More
+++ b/Show More