fix(heal): coalesce duplicate MRF intents

2026-08-23 04:39:04 +00:00 · 2026-08-23 09:05:45 +08:00
50 changed files with 1208 additions and 3106 deletions
@@ -39,10 +39,11 @@ jobs:
    env:
      FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: "true"
    steps:
-      - name: Checkout repository
+      - name: Checkout main branch
        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
        with:
          persist-credentials: false
+          ref: main

      - name: Setup Rust environment
        uses: ./.github/actions/setup
@@ -88,10 +89,11 @@ jobs:
      # either casing.
      NO_PROXY: 127.0.0.1,localhost
    steps:
-      - name: Checkout repository
+      - name: Checkout main branch
        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
        with:
          persist-credentials: false
+          ref: main

      - name: Setup Rust environment
        uses: ./.github/actions/setup
@@ -176,10 +178,11 @@ jobs:
      FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: "true"
      NO_PROXY: 127.0.0.1,localhost
    steps:
-      - name: Checkout repository
+      - name: Checkout main branch
        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
        with:
          persist-credentials: false
+          ref: main

      - name: Setup Rust environment
        uses: ./.github/actions/setup
@@ -30,8 +30,7 @@ make build-docker BUILD_OS=ubuntu22.04
 - Crate membership: `Cargo.toml` `[workspace].members`
 - Architecture, layering, crate map: [ARCHITECTURE.md](ARCHITECTURE.md)
 - Migration guardrails & readiness contracts: [docs/architecture/](docs/architecture/README.md)
- CI workflow steps: `.github/workflows/`; event, timeout, and required-status
-  matrix: [docs/testing/ci-gates.md](docs/testing/ci-gates.md)
+- CI gates: `.github/workflows/ci.yml` (source of truth; never copy its steps into docs)
 - Test-layer taxonomy, per-layer entry commands, serial/nextest rules, flake
  policy: [docs/testing/README.md](docs/testing/README.md)
 - Tier/ILM transition debugging (xl.meta inspection, versionId tracing):
@@ -70,8 +70,6 @@ make pre-pr

 > For the full test-layer taxonomy (unit / ecstore black-box / e2e / s3s-e2e / S3 compatibility / chaos / fuzz / bench), each layer's entry command, the naming conventions the migration gate depends on, and the serial/nextest rules, see [docs/testing/README.md](docs/testing/README.md).

-> For the event, timeout, required-status, and local reproduction matrix, see [docs/testing/ci-gates.md](docs/testing/ci-gates.md).
-
 ### 🔒 Automated Pre-commit Hooks
 #### What `make pre-commit` and `make pre-pr` actually run

@@ -1858,9 +1858,9 @@ dependencies = [

 [[package]]
 name = "cc"
-version = "1.4.4"
+version = "1.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ad534f4357a5264cce5019c989cf66a4f0dc4e0d1b1d15f8aacec0ff7360273"
+checksum = "509591b7bcd67f4ef775afad7662703b4935daaa6ec0e5605cfb1090b32a2b6d"
 dependencies = [
 "find-msvc-tools",
 "jobserver",
@@ -2522,6 +2522,12 @@ dependencies = [
 "subtle",
 ]

+[[package]]
+name = "cty"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b365fabc795046672053e29c954733ec3b05e4be654ab130fe8f1f94d7051f35"
+
 [[package]]
 name = "curve25519-dalek"
 version = "4.1.3"
@@ -5982,6 +5988,15 @@ version = "0.2.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6d2cec3eae94f9f509c767b45932f1ada8350c4bdb85af2fcab4a3c14807981"

+[[package]]
+name = "libmimalloc-sys"
+version = "0.1.49"
+source = "git+https://github.com/xonatius/mimalloc_rust.git?rev=6d4c41bb10c6d9da1d1b6f07b38c4cc051667f11#6d4c41bb10c6d9da1d1b6f07b38c4cc051667f11"
+dependencies = [
+ "cc",
+ "cty",
+]
+
 [[package]]
 name = "libredox"
 version = "0.1.20"
@@ -6382,6 +6397,14 @@ dependencies = [
 "synstructure 0.13.2",
 ]

+[[package]]
+name = "mimalloc"
+version = "0.1.52"
+source = "git+https://github.com/xonatius/mimalloc_rust.git?rev=6d4c41bb10c6d9da1d1b6f07b38c4cc051667f11#6d4c41bb10c6d9da1d1b6f07b38c4cc051667f11"
+dependencies = [
+ "libmimalloc-sys",
+]
+
 [[package]]
 name = "mime"
 version = "0.3.17"
@@ -9139,11 +9162,13 @@ dependencies = [
 "insta",
 "jiff",
 "libc",
+ "libmimalloc-sys",
 "libsystemd",
 "matchit 0.9.2",
 "md-5 0.11.0",
 "metrics",
 "metrics-util",
+ "mimalloc",
 "mime_guess",
 "opentelemetry",
 "opentelemetry_sdk",
@@ -9179,8 +9204,6 @@ dependencies = [
 "rustfs-lock",
 "rustfs-log-analyzer",
 "rustfs-madmin",
- "rustfs-mimalloc",
- "rustfs-mimalloc-sys",
 "rustfs-notify",
 "rustfs-object-capacity",
 "rustfs-object-data-cache",
@@ -9852,24 +9875,6 @@ dependencies = [
 "tokio",
 ]

-[[package]]
-name = "rustfs-mimalloc"
-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a406f4aa07084301d485beec873af6dccc8e3f8762da244743df92038b1db1a6"
-dependencies = [
- "rustfs-mimalloc-sys",
-]
-
-[[package]]
-name = "rustfs-mimalloc-sys"
-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3051b819175f58445d4c369a72f0ab88149f3885ba8bea2aff3be01f53fe7cd"
-dependencies = [
- "cc",
-]
-
 [[package]]
 name = "rustfs-notify"
 version = "1.0.0-rc.3"
@@ -350,8 +350,8 @@ russh-sftp = "2.4.0"
 dav-server = "0.11.0"

 # Performance Analysis and Memory Profiling
-rustfs-mimalloc = { version = "0.5.0" }
-rustfs-mimalloc-sys = { version = "0.5.0" }
+mimalloc = { version = "0.1.52", git = "https://github.com/xonatius/mimalloc_rust.git", rev = "6d4c41bb10c6d9da1d1b6f07b38c4cc051667f11" }
+libmimalloc-sys = { version = "0.1.49", git = "https://github.com/xonatius/mimalloc_rust.git", rev = "6d4c41bb10c6d9da1d1b6f07b38c4cc051667f11", features = ["extended"] }
 hotpath = { version = "0.23.3", default-features = false }
 # Snapshot testing for output format regression detection
 insta = { version = "1.48" }
@@ -23,21 +23,32 @@
 //! unconsumed intents is the consumer's job (see `rustfs-heal`
 //! `heal::mrf_queue`), mirroring MinIO's `.heal/mrf/list.bin`.

+use std::collections::HashMap;
+use std::collections::hash_map::RandomState;
+use std::hash::{BuildHasher, Hash};
+use std::sync::atomic::AtomicU64;
+use std::sync::atomic::AtomicUsize;
 use std::sync::{
-    Arc, OnceLock,
+    Arc, Mutex, OnceLock,
    atomic::{AtomicBool, Ordering},
 };
+use std::time::{Duration, Instant};
 use tokio::sync::mpsc;
 use uuid::Uuid;

 /// Bounded capacity of the global MRF channel. Backpressure is resolved by
 /// dropping (and counting) intents, never by blocking the producer.
 const MRF_CHANNEL_CAPACITY: usize = 8192;
+const MRF_COALESCER_SHARDS: usize = 16;
+const MRF_COALESCER_MAX_KEYS: usize = 8192;
+const MRF_COALESCER_MAX_BYTES: usize = 16 * 1024 * 1024;
+const MRF_COALESCER_TTL: Duration = Duration::from_secs(60);
+const MRF_MAX_IDENTITY_COMPONENT: usize = 1024;

 /// Why an intent was produced. Drives the heal priority mapping on the
 /// consumer side (DecodeFailure -> Urgent, MetadataCorruption -> High,
 /// PartialWrite -> Normal).
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum MrfKind {
    /// Erasure decode failed while serving a read (read path).
    DecodeFailure,
@@ -67,12 +78,52 @@ pub struct MrfIntent {
    /// Version the intent targets, as raw UUID bytes.
    pub version_id: Option<[u8; 16]>,
    pub kind: MrfKind,
+    /// Stable erasure-set scope when the producer has it. Kept optional so
+    /// metadata corruption and legacy producers do not invent a scope.
+    pub scope: Option<MrfScope>,
+    /// Generation of the node-local ingress lease. It is not persisted in
+    /// the journal; replayed records acquire a fresh lease when re-enqueued.
+    pub lease: Option<MrfIngressLease>,
    pub enqueued_at_ms: u64,
    /// Times this intent has already been offered to the heal manager.
    /// Dropped by the consumer once it reaches `MRF_MAX_ATTEMPTS`.
    pub attempts: u8,
 }

+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct MrfScope {
+    pub pool_index: u32,
+    pub set_index: u32,
+}
+
+/// Opaque generation used to release exactly the admission that created an
+/// ingress entry. A generation prevents a late terminal callback from
+/// deleting a newer retry for the same identity (ABA).
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct MrfIngressLease(u64);
+
+impl MrfIngressLease {
+    const fn new(value: u64) -> Self {
+        Self(value)
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum MrfDropReason {
+    Disabled,
+    Uninitialized,
+    Full,
+    OversizedIdentity,
+    CoalescerFull,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum MrfIngressResult {
+    Enqueued,
+    Coalesced,
+    Dropped(MrfDropReason),
+}
+
 /// Consumer-side retry ceiling before an intent is given up on.
 pub const MRF_MAX_ATTEMPTS: u8 = 3;

@@ -87,6 +138,159 @@ impl MrfIntent {

 static GLOBAL_MRF_SENDER: OnceLock<mpsc::Sender<MrfIntent>> = OnceLock::new();

+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+struct MrfIdentityKey {
+    kind: MrfKind,
+    bucket: Arc<str>,
+    object: Arc<str>,
+    version_id: Option<[u8; 16]>,
+    scope: Option<MrfScope>,
+}
+
+#[derive(Debug)]
+struct IngressEntry {
+    lease: MrfIngressLease,
+    expires_at: Instant,
+    bytes: usize,
+}
+
+type MrfCoalescerShard = Mutex<HashMap<MrfIdentityKey, IngressEntry>>;
+type MrfCoalescer = Box<[MrfCoalescerShard]>;
+
+static MRF_COALESCER: OnceLock<MrfCoalescer> = OnceLock::new();
+static NEXT_MRF_LEASE: AtomicU64 = AtomicU64::new(1);
+static MRF_COALESCER_COUNT: AtomicUsize = AtomicUsize::new(0);
+static MRF_COALESCER_BYTES: AtomicUsize = AtomicUsize::new(0);
+static MRF_HASH_STATE: OnceLock<RandomState> = OnceLock::new();
+
+fn coalescer() -> &'static [MrfCoalescerShard] {
+    MRF_COALESCER.get_or_init(|| {
+        (0..MRF_COALESCER_SHARDS)
+            .map(|_| Mutex::new(HashMap::new()))
+            .collect::<Vec<_>>()
+            .into_boxed_slice()
+    })
+}
+
+fn key_shard(key: &MrfIdentityKey) -> usize {
+    let hash = MRF_HASH_STATE.get_or_init(RandomState::new).hash_one(key);
+    usize::try_from(hash).unwrap_or(0) % MRF_COALESCER_SHARDS
+}
+
+fn canonical_version(version_id: Option<Uuid>) -> Option<[u8; 16]> {
+    version_id
+        .filter(|version| !version.is_nil())
+        .map(|version| *version.as_bytes())
+}
+
+fn canonical_identity(
+    kind: MrfKind,
+    version_id: Option<[u8; 16]>,
+    scope: Option<MrfScope>,
+) -> (Option<[u8; 16]>, Option<MrfScope>) {
+    let version_id = version_id.filter(|bytes| *bytes != [0; 16]);
+    match kind {
+        MrfKind::MetadataCorruption => (None, None),
+        MrfKind::DecodeFailure | MrfKind::PartialWrite => (version_id, scope),
+    }
+}
+
+fn identity_estimated_bytes(key: &MrfIdentityKey) -> usize {
+    64usize
+        .saturating_add(key.bucket.len())
+        .saturating_add(key.object.len())
+        .saturating_add(key.version_id.map_or(0, |_| 16))
+        .saturating_add(key.scope.map_or(0, |_| 8))
+}
+
+fn reserve(counter: &AtomicUsize, limit: usize, amount: usize) -> bool {
+    let mut current = counter.load(Ordering::Relaxed);
+    loop {
+        let Some(next) = current.checked_add(amount) else {
+            return false;
+        };
+        if next > limit {
+            return false;
+        }
+        match counter.compare_exchange_weak(current, next, Ordering::Relaxed, Ordering::Relaxed) {
+            Ok(_) => return true,
+            Err(observed) => current = observed,
+        }
+    }
+}
+
+fn coalescer_admit(key: MrfIdentityKey) -> Result<MrfIngressLease, MrfIngressResult> {
+    let shard = key_shard(&key);
+    let mut entries = coalescer()[shard]
+        .lock()
+        .map_err(|_| MrfIngressResult::Dropped(MrfDropReason::CoalescerFull))?;
+    let now = Instant::now();
+    let before = entries.len();
+    let mut expired_bytes = 0usize;
+    entries.retain(|_, entry| {
+        if entry.expires_at > now {
+            true
+        } else {
+            expired_bytes = expired_bytes.saturating_add(entry.bytes);
+            false
+        }
+    });
+    let evicted = before.saturating_sub(entries.len());
+    if evicted > 0 {
+        MRF_COALESCER_COUNT.fetch_sub(evicted, Ordering::Relaxed);
+        MRF_COALESCER_BYTES.fetch_sub(expired_bytes, Ordering::Relaxed);
+        let evicted = u64::try_from(evicted).unwrap_or(u64::MAX);
+        metrics::counter!("rustfs_heal_mrf_coalescer_expired_total").increment(evicted);
+        metrics::counter!("rustfs_heal_mrf_coalescer_evictions_total").increment(evicted);
+    }
+    if entries.contains_key(&key) {
+        metrics::counter!("rustfs_heal_mrf_coalesced_total").increment(1);
+        return Err(MrfIngressResult::Coalesced);
+    }
+    let bytes = identity_estimated_bytes(&key);
+    let count_reserved = reserve(&MRF_COALESCER_COUNT, MRF_COALESCER_MAX_KEYS, 1);
+    let bytes_reserved = count_reserved && reserve(&MRF_COALESCER_BYTES, MRF_COALESCER_MAX_BYTES, bytes);
+    if !count_reserved || !bytes_reserved {
+        if count_reserved {
+            MRF_COALESCER_COUNT.fetch_sub(1, Ordering::Relaxed);
+        }
+        metrics::counter!("rustfs_heal_mrf_dropped_total", "reason" => "coalescer_full").increment(1);
+        return Err(MrfIngressResult::Dropped(MrfDropReason::CoalescerFull));
+    }
+    let lease = MrfIngressLease::new(NEXT_MRF_LEASE.fetch_add(1, Ordering::Relaxed));
+    if entries
+        .insert(
+            key,
+            IngressEntry {
+                lease,
+                expires_at: now + MRF_COALESCER_TTL,
+                bytes,
+            },
+        )
+        .is_some()
+    {
+        MRF_COALESCER_COUNT.fetch_sub(1, Ordering::Relaxed);
+        MRF_COALESCER_BYTES.fetch_sub(bytes, Ordering::Relaxed);
+        metrics::counter!("rustfs_heal_mrf_coalesced_total").increment(1);
+        return Err(MrfIngressResult::Coalesced);
+    }
+    Ok(lease)
+}
+
+fn coalescer_release(key: &MrfIdentityKey, lease: Option<MrfIngressLease>) {
+    let Some(lease) = lease else {
+        return;
+    };
+    if let Ok(mut entries) = coalescer()[key_shard(key)].lock() {
+        let should_remove = entries.get(key).is_some_and(|entry| entry.lease == lease);
+        if should_remove {
+            let bytes = entries.remove(key).map(|entry| entry.bytes).unwrap_or(0);
+            MRF_COALESCER_COUNT.fetch_sub(1, Ordering::Relaxed);
+            MRF_COALESCER_BYTES.fetch_sub(bytes, Ordering::Relaxed);
+        }
+    }
+}
+
 /// Delivery kill-switch, set from `RUSTFS_HEAL_MRF_ENABLE`. Producers check
 /// this before touching the channel so the disabled path stays allocation- and
 /// sync-free.
@@ -122,21 +326,90 @@ pub fn init_mrf_channel() -> Result<mpsc::Receiver<MrfIntent>, &'static str> {
 /// This runs on IO error paths, so it stays synchronous and cheap: one
 /// bounded allocation for the two `Arc<str>` handles plus the channel slot.
 pub fn try_send_mrf_intent(kind: MrfKind, bucket: &str, object: &str, version_id: Option<Uuid>) -> bool {
+    matches!(
+        try_send_mrf_intent_typed(kind, bucket, object, version_id, None),
+        MrfIngressResult::Enqueued
+    )
+}
+
+/// Typed ingress result. `Coalesced` means an equivalent in-flight channel
+/// intent already exists; it is not a second executable or durable admission.
+pub fn try_send_mrf_intent_typed(
+    kind: MrfKind,
+    bucket: &str,
+    object: &str,
+    version_id: Option<Uuid>,
+    scope: Option<MrfScope>,
+) -> MrfIngressResult {
    if !mrf_delivery_enabled() {
-        return false;
+        return MrfIngressResult::Dropped(MrfDropReason::Disabled);
    }
    let Some(sender) = GLOBAL_MRF_SENDER.get() else {
-        return false;
+        return MrfIngressResult::Dropped(MrfDropReason::Uninitialized);
    };
-    let intent = MrfIntent {
+    if bucket.len() > MRF_MAX_IDENTITY_COMPONENT || object.len() > MRF_MAX_IDENTITY_COMPONENT {
+        return MrfIngressResult::Dropped(MrfDropReason::OversizedIdentity);
+    }
+    let (version_id, scope) = canonical_identity(kind, canonical_version(version_id), scope);
+    let key = MrfIdentityKey {
+        kind,
        bucket: Arc::from(bucket),
        object: Arc::from(object),
-        version_id: version_id.map(|vid| *vid.as_bytes()),
+        version_id,
+        scope,
+    };
+    let lease = match coalescer_admit(key.clone()) {
+        Ok(lease) => lease,
+        Err(result) => return result,
+    };
+    let intent = MrfIntent {
+        bucket: key.bucket.clone(),
+        object: key.object.clone(),
+        version_id: key.version_id,
        kind,
+        scope,
+        lease: Some(lease),
        enqueued_at_ms: unix_now_ms(),
        attempts: 0,
    };
-    sender.try_send(intent).is_ok()
+    match sender.try_send(intent) {
+        Ok(()) => MrfIngressResult::Enqueued,
+        Err(mpsc::error::TrySendError::Full(_)) => {
+            coalescer_release(&key, Some(lease));
+            metrics::counter!("rustfs_heal_mrf_dropped_total", "reason" => "channel_full").increment(1);
+            MrfIngressResult::Dropped(MrfDropReason::Full)
+        }
+        Err(mpsc::error::TrySendError::Closed(_)) => {
+            coalescer_release(&key, Some(lease));
+            MrfIngressResult::Dropped(MrfDropReason::Uninitialized)
+        }
+    }
+}
+
+/// Release the ingress key once the consumer owns the intent.
+pub fn release_mrf_intent(intent: &MrfIntent) {
+    release_mrf_identity(intent.kind, &intent.bucket, &intent.object, intent.version_id, intent.scope, intent.lease);
+}
+
+pub fn release_mrf_identity(
+    kind: MrfKind,
+    bucket: &str,
+    object: &str,
+    version_id: Option<[u8; 16]>,
+    scope: Option<MrfScope>,
+    lease: Option<MrfIngressLease>,
+) {
+    let (version_id, scope) = canonical_identity(kind, version_id, scope);
+    coalescer_release(
+        &MrfIdentityKey {
+            kind,
+            bucket: Arc::from(bucket),
+            object: Arc::from(object),
+            version_id,
+            scope,
+        },
+        lease,
+    );
 }

 fn unix_now_ms() -> u64 {
@@ -144,7 +417,8 @@ fn unix_now_ms() -> u64 {
    // failure would be a bug rather than something to handle here.
    std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
-        .map(|d| d.as_millis() as u64)
+        .ok()
+        .and_then(|d| u64::try_from(d.as_millis()).ok())
        .unwrap_or(0)
 }

@@ -215,12 +489,60 @@ mod tests {
            object: Arc::from("object"),
            version_id: Some([0u8; 16]),
            kind: MrfKind::DecodeFailure,
+            scope: None,
+            lease: None,
            enqueued_at_ms: 0,
            attempts: 0,
        };
        assert!(intent.estimated_bytes() >= intent.bucket.len() + intent.object.len());
    }

+    #[test]
+    fn ingress_duplicate_identity_coalesces_and_releases_for_retry() {
+        let key = MrfIdentityKey {
+            kind: MrfKind::DecodeFailure,
+            bucket: Arc::from("ingress-test-bucket"),
+            object: Arc::from("ingress-test-object"),
+            version_id: Some([9; 16]),
+            scope: Some(MrfScope {
+                pool_index: 3,
+                set_index: 4,
+            }),
+        };
+        let lease = coalescer_admit(key.clone()).expect("first identity should be admitted");
+        for _ in 0..999 {
+            assert_eq!(coalescer_admit(key.clone()), Err(MrfIngressResult::Coalesced));
+        }
+        coalescer_release(&key, Some(lease));
+        let retry_lease = coalescer_admit(key.clone()).expect("released identity must admit a retry");
+        coalescer_release(&key, Some(retry_lease));
+    }
+
+    #[test]
+    fn ingress_identity_preserves_kind_scope_and_version_boundaries() {
+        let (nil_version, nil_scope) = canonical_identity(
+            MrfKind::DecodeFailure,
+            Some([0; 16]),
+            Some(MrfScope {
+                pool_index: 1,
+                set_index: 2,
+            }),
+        );
+        assert_eq!(nil_version, None, "nil UUID is the unversioned identity");
+        assert!(nil_scope.is_some());
+
+        let (metadata_version, metadata_scope) = canonical_identity(
+            MrfKind::MetadataCorruption,
+            Some([7; 16]),
+            Some(MrfScope {
+                pool_index: 1,
+                set_index: 2,
+            }),
+        );
+        assert_eq!(metadata_version, None);
+        assert_eq!(metadata_scope, None);
+    }
+
    #[tokio::test]
    async fn try_send_delivers_and_respects_capacity() {
        let mut receiver = init_mrf_channel().expect("first initialization should succeed");
@@ -230,6 +552,7 @@ mod tests {
        let intent = receiver.recv().await.expect("intent should arrive");
        assert_eq!(intent.kind, MrfKind::DecodeFailure);
        assert_eq!(intent.bucket.as_ref(), "b");
+        release_mrf_intent(&intent);

        // Disable delivery: producers become no-ops.
        set_mrf_delivery_enabled(false);
@@ -239,8 +562,8 @@ mod tests {
        // Fill the bounded channel past capacity: excess intents are dropped,
        // never blocking.
        let mut accepted = 0;
-        for _ in 0..(MRF_CHANNEL_CAPACITY + 64) {
-            if try_send_mrf_intent(MrfKind::PartialWrite, "b", "o", None) {
+        for index in 0..(MRF_CHANNEL_CAPACITY + 64) {
+            if try_send_mrf_intent(MrfKind::PartialWrite, "b", &format!("o-{index}"), None) {
                accepted += 1;
            }
        }
@@ -12,13 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

-use serde::{
-    Deserialize, Serialize,
-    de::{IgnoredAny, SeqAccess, Visitor},
-    ser::SerializeMap as _,
-};
+use serde::{Deserialize, Serialize, ser::SerializeMap as _};
 use std::{
-    borrow::Cow,
    collections::{HashMap, HashSet},
    hash::{DefaultHasher, Hash, Hasher},
    time::{Duration, SystemTime},
@@ -53,11 +48,6 @@ pub const DATA_USAGE_OBSERVED_OBJECT_NAME: &str = ".usage.observed.json";
 // RUSTFS_COMPAT_TODO(scanner-usage-v2): keep .usage.json readable and removable during rolling upgrades from pre-v2 scanners. Remove after supported direct-upgrade sources all write .usage.v2.json.
 pub const LEGACY_DATA_USAGE_OBJECT_NAME: &str = ".usage.json";

-/// Fixed bucket for objects whose storage class is not in the scanner's
-/// cycle-local tier registry.  Keeping this key fixed prevents untrusted or
-/// stale tier names from growing persisted per-tier maps without bound.
-pub const UNKNOWN_TIER: &str = "UNKNOWN_TIER";
-
 /// Returns true when `existing_last_update` is ahead of `now` by more than
 /// [`USAGE_LAST_UPDATE_FUTURE_TOLERANCE`], i.e. the persisted timestamp cannot be
 /// trusted for staleness comparisons and a fresh snapshot save must be allowed.
@@ -88,301 +78,12 @@ impl TierStats {
            && self.num_objects.checked_add(u.num_objects).is_some()
    }

-    /// Add tier counters without allowing a counter to wrap.
-    pub fn checked_add(&self, u: &TierStats) -> Option<TierStats> {
-        Some(TierStats {
-            total_size: self.total_size.checked_add(u.total_size)?,
-            num_versions: self.num_versions.checked_add(u.num_versions)?,
-            num_objects: self.num_objects.checked_add(u.num_objects)?,
-        })
-    }
-
    /// True when this tier contributed nothing, i.e. merging it is a no-op.
    pub fn is_empty(&self) -> bool {
        self.total_size == 0 && self.num_versions == 0 && self.num_objects == 0
    }
 }

-/// Bounded diagnostics for objects whose tier is absent from the cycle
-/// registry. Counters are authoritative; diagnostics are only a small,
-/// redacted reconciliation aid and may be dropped at the configured caps.
-pub const UNKNOWN_TIER_DIAGNOSTIC_ENTRY_CAP: usize = 64;
-pub const UNKNOWN_TIER_DIAGNOSTIC_BYTE_CAP: usize = 4096;
-pub const UNKNOWN_TIER_DIAGNOSTIC_TTL: Duration = Duration::from_secs(60 * 60);
-const UNKNOWN_TIER_DIAGNOSTIC_KEY_BYTES: usize = 256;
-const UNKNOWN_TIER_DIAGNOSTIC_INPUT_CAP: usize = UNKNOWN_TIER_DIAGNOSTIC_ENTRY_CAP * 4;
-
-#[derive(Clone, Debug, Default, Serialize, PartialEq, Eq)]
-pub struct UnknownTierStats {
-    /// Logical bytes retained in the scanner's normal usage total.
-    pub unknown_bytes: u64,
-    /// Physical bytes recorded in the per-tier accounting dimension.
-    ///
-    /// Older writers only had `unknown_bytes`; decoding those snapshots keeps
-    /// this field at zero and the scanner fills it for new observations.
-    #[serde(default)]
-    pub unknown_physical_bytes: u64,
-    pub unknown_objects: u64,
-    pub unknown_versions: u64,
-    pub diagnostics_dropped: u64,
-    #[serde(default)]
-    pub diagnostics: Vec<String>,
-    #[serde(default)]
-    pub diagnostics_at: Option<SystemTime>,
-    /// A saturating update occurred; this snapshot cannot prove conservation.
-    /// The field is persisted so a restarted scanner cannot mistake a
-    /// saturated legacy aggregate for exact accounting evidence.
-    #[serde(default)]
-    pub counter_overflowed: bool,
-}
-
-#[derive(Default)]
-struct BoundedDiagnostics {
-    entries: Vec<String>,
-    dropped: u64,
-}
-
-impl<'de> Deserialize<'de> for BoundedDiagnostics {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        struct BoundedDiagnosticsVisitor;
-
-        impl<'de> Visitor<'de> for BoundedDiagnosticsVisitor {
-            type Value = BoundedDiagnostics;
-
-            fn expecting(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-                formatter.write_str("a sequence of bounded tier diagnostics")
-            }
-
-            fn visit_seq<A>(self, mut sequence: A) -> Result<Self::Value, A::Error>
-            where
-                A: SeqAccess<'de>,
-            {
-                let mut bounded = BoundedDiagnostics::default();
-                let mut bytes = 0_usize;
-                let mut inspected = 0_usize;
-                loop {
-                    if bounded.entries.len() >= UNKNOWN_TIER_DIAGNOSTIC_ENTRY_CAP
-                        || bytes >= UNKNOWN_TIER_DIAGNOSTIC_BYTE_CAP
-                        || inspected >= UNKNOWN_TIER_DIAGNOSTIC_INPUT_CAP
-                    {
-                        if sequence.next_element::<IgnoredAny>()?.is_none() {
-                            break;
-                        }
-                        bounded.dropped = bounded.dropped.saturating_add(1);
-                        continue;
-                    }
-                    let Some(diagnostic) = sequence.next_element::<Cow<'de, str>>()? else {
-                        break;
-                    };
-                    inspected = inspected.saturating_add(1);
-                    if !is_redacted_tier_diagnostic(&diagnostic)
-                        || bytes.saturating_add(diagnostic.len()) > UNKNOWN_TIER_DIAGNOSTIC_BYTE_CAP
-                        || bounded.entries.iter().any(|entry| entry == &diagnostic)
-                    {
-                        bounded.dropped = bounded.dropped.saturating_add(1);
-                        continue;
-                    }
-                    bytes = bytes.saturating_add(diagnostic.len());
-                    bounded.entries.push(diagnostic.into_owned());
-                }
-                Ok(bounded)
-            }
-        }
-
-        deserializer.deserialize_seq(BoundedDiagnosticsVisitor)
-    }
-}
-
-#[derive(Deserialize)]
-struct UnknownTierStatsWire {
-    #[serde(default)]
-    unknown_bytes: u64,
-    #[serde(default)]
-    unknown_physical_bytes: u64,
-    #[serde(default)]
-    unknown_objects: u64,
-    #[serde(default)]
-    unknown_versions: u64,
-    #[serde(default)]
-    diagnostics_dropped: u64,
-    #[serde(default)]
-    diagnostics: BoundedDiagnostics,
-    #[serde(default)]
-    diagnostics_at: Option<SystemTime>,
-    #[serde(default)]
-    counter_overflowed: bool,
-}
-
-fn is_redacted_tier_diagnostic(diagnostic: &str) -> bool {
-    diagnostic
-        .strip_prefix("tier-hash:")
-        .is_some_and(|digest| digest.len() == 16 && digest.bytes().all(|byte| byte.is_ascii_hexdigit()))
-}
-
-fn diagnostics_expired(at: SystemTime, now: SystemTime) -> bool {
-    now.duration_since(at).map_or(true, |age| age > UNKNOWN_TIER_DIAGNOSTIC_TTL)
-}
-
-fn checked_saturating_add(left: u64, right: u64, overflowed: &mut bool) -> u64 {
-    match left.checked_add(right) {
-        Some(value) => value,
-        None => {
-            *overflowed = true;
-            u64::MAX
-        }
-    }
-}
-
-impl<'de> Deserialize<'de> for UnknownTierStats {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        let wire = UnknownTierStatsWire::deserialize(deserializer)?;
-        let mut stats = Self {
-            unknown_bytes: wire.unknown_bytes,
-            unknown_physical_bytes: wire.unknown_physical_bytes,
-            unknown_objects: wire.unknown_objects,
-            unknown_versions: wire.unknown_versions,
-            counter_overflowed: wire.counter_overflowed,
-            diagnostics_dropped: wire.diagnostics_dropped,
-            diagnostics: wire.diagnostics.entries,
-            diagnostics_at: wire.diagnostics_at,
-        };
-        stats.diagnostics_dropped =
-            checked_saturating_add(stats.diagnostics_dropped, wire.diagnostics.dropped, &mut stats.counter_overflowed);
-        if stats
-            .diagnostics_at
-            .is_some_and(|at| diagnostics_expired(at, SystemTime::now()))
-        {
-            stats.diagnostics.clear();
-            stats.diagnostics_at = None;
-        }
-        Ok(stats)
-    }
-}
-
-impl UnknownTierStats {
-    /// Record one observation where the logical and physical dimensions are
-    /// the same. Kept as a small compatibility helper for callers that only
-    /// have one size value.
-    pub fn record(&mut self, tier: &str, bytes: u64, versions: u64, objects: u64) {
-        self.record_dimensions(tier, bytes, bytes, versions, objects);
-    }
-
-    /// Record one observation without conflating logical usage with physical
-    /// tier bytes. Both counters are saturating so malformed metadata cannot
-    /// wrap an aggregate.
-    pub fn record_dimensions(&mut self, tier: &str, logical_bytes: u64, physical_bytes: u64, versions: u64, objects: u64) {
-        self.unknown_bytes = checked_saturating_add(self.unknown_bytes, logical_bytes, &mut self.counter_overflowed);
-        self.unknown_physical_bytes =
-            checked_saturating_add(self.unknown_physical_bytes, physical_bytes, &mut self.counter_overflowed);
-        self.unknown_objects = checked_saturating_add(self.unknown_objects, objects, &mut self.counter_overflowed);
-        self.unknown_versions = checked_saturating_add(self.unknown_versions, versions, &mut self.counter_overflowed);
-
-        let digest = {
-            let mut hasher = DefaultHasher::new();
-            // Bound hashing work for hostile metadata while retaining enough
-            // length/prefix entropy to reconcile repeated observations.
-            hasher.write_u64(u64::try_from(tier.len()).unwrap_or(u64::MAX));
-            let bounded = &tier.as_bytes()[..tier.len().min(UNKNOWN_TIER_DIAGNOSTIC_KEY_BYTES)];
-            hasher.write(bounded);
-            hasher.write_u8(u8::from(bounded.iter().any(|byte| byte.is_ascii_control())));
-            format!("tier-hash:{:016x}", hasher.finish())
-        };
-        let now = SystemTime::now();
-        if self.diagnostics_at.is_some_and(|at| diagnostics_expired(at, now)) {
-            self.diagnostics.clear();
-        }
-        self.diagnostics_at = Some(now);
-        if self.diagnostics.iter().any(|entry| entry == &digest) {
-            return;
-        }
-        let current_bytes: usize = self.diagnostics.iter().map(String::len).sum();
-        if self.diagnostics.len() >= UNKNOWN_TIER_DIAGNOSTIC_ENTRY_CAP
-            || current_bytes.saturating_add(digest.len()) > UNKNOWN_TIER_DIAGNOSTIC_BYTE_CAP
-        {
-            self.diagnostics_dropped = checked_saturating_add(1, self.diagnostics_dropped, &mut self.counter_overflowed);
-            return;
-        }
-        self.diagnostics.push(digest);
-    }
-
-    pub fn merge(&mut self, other: &Self) {
-        self.unknown_bytes = checked_saturating_add(self.unknown_bytes, other.unknown_bytes, &mut self.counter_overflowed);
-        self.unknown_physical_bytes =
-            checked_saturating_add(self.unknown_physical_bytes, other.unknown_physical_bytes, &mut self.counter_overflowed);
-        self.unknown_objects = checked_saturating_add(self.unknown_objects, other.unknown_objects, &mut self.counter_overflowed);
-        self.unknown_versions =
-            checked_saturating_add(self.unknown_versions, other.unknown_versions, &mut self.counter_overflowed);
-        self.diagnostics_dropped =
-            checked_saturating_add(self.diagnostics_dropped, other.diagnostics_dropped, &mut self.counter_overflowed);
-        self.counter_overflowed |= other.counter_overflowed;
-        let now = SystemTime::now();
-        if self.diagnostics_at.is_some_and(|at| diagnostics_expired(at, now)) {
-            self.diagnostics.clear();
-            self.diagnostics_at = None;
-        }
-        if !other.diagnostics_at.is_some_and(|at| diagnostics_expired(at, now)) {
-            for diagnostic in &other.diagnostics {
-                if !is_redacted_tier_diagnostic(diagnostic) {
-                    self.diagnostics_dropped = checked_saturating_add(1, self.diagnostics_dropped, &mut self.counter_overflowed);
-                    continue;
-                }
-                if self.diagnostics.iter().any(|entry| entry == diagnostic) {
-                    continue;
-                }
-                let current_bytes: usize = self.diagnostics.iter().map(String::len).sum();
-                if self.diagnostics.len() >= UNKNOWN_TIER_DIAGNOSTIC_ENTRY_CAP
-                    || current_bytes.saturating_add(diagnostic.len()) > UNKNOWN_TIER_DIAGNOSTIC_BYTE_CAP
-                {
-                    self.diagnostics_dropped = checked_saturating_add(1, self.diagnostics_dropped, &mut self.counter_overflowed);
-                    continue;
-                }
-                self.diagnostics.push(diagnostic.clone());
-            }
-        }
-        if !self.diagnostics.is_empty() {
-            self.diagnostics_at = Some(now);
-        }
-    }
-
-    pub fn fits_add(&self, other: &Self) -> bool {
-        !self.counter_overflowed
-            && !other.counter_overflowed
-            && self.unknown_bytes.checked_add(other.unknown_bytes).is_some()
-            && self
-                .unknown_physical_bytes
-                .checked_add(other.unknown_physical_bytes)
-                .is_some()
-            && self.unknown_objects.checked_add(other.unknown_objects).is_some()
-            && self.unknown_versions.checked_add(other.unknown_versions).is_some()
-            && self.diagnostics_dropped.checked_add(other.diagnostics_dropped).is_some()
-    }
-
-    pub fn checked_add(&self, other: &Self) -> Option<Self> {
-        if !self.fits_add(other) {
-            return None;
-        }
-        let mut merged = self.clone();
-        merged.merge(other);
-        Some(merged)
-    }
-
-    pub fn is_empty(&self) -> bool {
-        !self.counter_overflowed
-            && self.unknown_bytes == 0
-            && self.unknown_physical_bytes == 0
-            && self.unknown_objects == 0
-            && self.unknown_versions == 0
-            && self.diagnostics_dropped == 0
-            && self.diagnostics.is_empty()
-    }
-}
-
 #[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq)]
 pub struct AllTierStats {
    pub tiers: HashMap<String, TierStats>,
@@ -423,31 +124,6 @@ impl AllTierStats {
            .iter()
            .all(|(tier, right)| self.tiers.get(tier).is_none_or(|left| left.fits_add(right)))
    }
-
-    /// Fold keys from an older cache that are no longer present in the
-    /// current registry into the fixed unknown bucket. Built-in storage
-    /// classes remain known even when no remote tier is configured.
-    pub fn fold_unknown_tiers<'a, I>(&mut self, known_tiers: I)
-    where
-        I: IntoIterator<Item = &'a str>,
-    {
-        let known: HashSet<&str> = known_tiers.into_iter().collect();
-        let mut unknown = self.tiers.remove(UNKNOWN_TIER).unwrap_or_default();
-        let retired_tiers: Vec<String> = self
-            .tiers
-            .keys()
-            .filter(|tier| tier.as_str() != "STANDARD" && tier.as_str() != "REDUCED_REDUNDANCY" && !known.contains(tier.as_str()))
-            .cloned()
-            .collect();
-        for tier in retired_tiers {
-            if let Some(stats) = self.tiers.remove(&tier) {
-                unknown = unknown.add(&stats);
-            }
-        }
-        if !unknown.is_empty() {
-            self.tiers.insert(UNKNOWN_TIER.to_string(), unknown);
-        }
-    }
 }

 /// Bucket target usage info provides replication statistics
@@ -535,10 +211,6 @@ pub struct DataUsageInfo {
    /// tier exists, so an absent value means "not accounted", never "zero".
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub tier_stats: Option<AllTierStats>,
-    /// Bounded diagnostics and separate logical/physical counters for objects
-    /// classified into [`UNKNOWN_TIER`].
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub unknown_tier_stats: Option<UnknownTierStats>,

    /// Total number of buckets in this cluster
    pub buckets_count: u64,
@@ -635,48 +307,6 @@ pub struct DiskUsageStatus {
    pub snapshot_exists: bool,
 }

-/// Independent conservation evidence for a scanner summary.
-///
-/// The totals are maintained while objects are accounted and are deliberately
-/// not reconstructed from the tier map at publish time. `*_known` records the
-/// portion represented by the corresponding accounting dimension.
-#[derive(Debug, Default, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
-pub struct TierAccountingProof {
-    pub logical_total: u64,
-    pub logical_known: u64,
-    pub physical_total: u64,
-    pub physical_known: u64,
-    #[serde(default)]
-    pub overflowed: bool,
-}
-
-impl TierAccountingProof {
-    pub fn checked_add(self, other: Self) -> Option<Self> {
-        if self.overflowed || other.overflowed {
-            return None;
-        }
-        Some(Self {
-            logical_total: self.logical_total.checked_add(other.logical_total)?,
-            logical_known: self.logical_known.checked_add(other.logical_known)?,
-            physical_total: self.physical_total.checked_add(other.physical_total)?,
-            physical_known: self.physical_known.checked_add(other.physical_known)?,
-            overflowed: false,
-        })
-    }
-
-    pub fn saturating_add(&mut self, other: Self) {
-        let Some(merged) = (*self).checked_add(other) else {
-            self.logical_total = self.logical_total.saturating_add(other.logical_total);
-            self.logical_known = self.logical_known.saturating_add(other.logical_known);
-            self.physical_total = self.physical_total.saturating_add(other.physical_total);
-            self.physical_known = self.physical_known.saturating_add(other.physical_known);
-            self.overflowed = true;
-            return;
-        };
-        *self = merged;
-    }
-}
-
 /// Size summary for a single object or group of objects
 #[derive(Debug, Default, Clone)]
 pub struct SizeSummary {
@@ -706,10 +336,6 @@ pub struct SizeSummary {
    pub repl_target_stats: HashMap<String, ReplTargetSizeSummary>,
    /// Per-tier accounting, keyed by storage class or remote tier name
    pub tier_stats: HashMap<String, TierStats>,
-    /// Counters and bounded diagnostics for unknown tiers in this summary.
-    pub unknown_tier_stats: UnknownTierStats,
-    /// Independent logical/physical conservation evidence.
-    pub tier_accounting_proof: TierAccountingProof,
 }

 /// Replication target size summary
@@ -801,10 +427,6 @@ impl<'de> Deserialize<'de> for SizeHistogram {
 }

 impl SizeHistogram {
-    pub fn is_empty(&self) -> bool {
-        self.0.iter().all(|value| *value == 0)
-    }
-
    pub fn add(&mut self, size: u64) {
        let intervals = [
            (0, 1024 - 1),                              // LESS_THAN_1024_B
@@ -919,10 +541,6 @@ impl<'de> Deserialize<'de> for VersionsHistogram {
 }

 impl VersionsHistogram {
-    pub fn is_empty(&self) -> bool {
-        self.0.iter().all(|value| *value == 0)
-    }
-
    pub fn add(&mut self, count: u64) {
        let intervals = [
            (0, 0),            // UNVERSIONED
@@ -1063,13 +681,6 @@ pub struct DataUsageEntry {
    /// observed tier-classified objects.
    #[serde(default)]
    pub all_tier_stats: Option<AllTierStats>,
-    /// Bounded unknown-tier reconciliation state for this cache entry.
-    #[serde(default)]
-    pub unknown_tier_stats: Option<UnknownTierStats>,
-    /// Optional conservation proof. Missing values are legacy/unproven, not
-    /// zero-valued evidence.
-    #[serde(default)]
-    pub tier_accounting_proof: Option<TierAccountingProof>,
 }

 impl Serialize for DataUsageEntry {
@@ -1080,9 +691,7 @@ impl Serialize for DataUsageEntry {
        // Keep entries map-encoded so older readers can ignore fields appended
        // by newer scanner versions during rolling upgrades. The derived
        // (array) encoding made any appended field a decode error for them.
-        let mut state = serializer.serialize_map(Some(
-            11 + usize::from(self.unknown_tier_stats.is_some()) + usize::from(self.tier_accounting_proof.is_some()),
-        ))?;
+        let mut state = serializer.serialize_map(Some(11))?;
        state.serialize_entry("children", &self.children)?;
        state.serialize_entry("size", &self.size)?;
        state.serialize_entry("objects", &self.objects)?;
@@ -1094,35 +703,11 @@ impl Serialize for DataUsageEntry {
        state.serialize_entry("compacted", &self.compacted)?;
        state.serialize_entry("failed_objects", &self.failed_objects)?;
        state.serialize_entry("all_tier_stats", &self.all_tier_stats)?;
-        // Keep the legacy no-unknown shape byte-for-byte stable. Once unknown
-        // accounting exists, append its map field before the optional proof.
-        if let Some(unknown_tier_stats) = self.unknown_tier_stats.as_ref() {
-            state.serialize_entry("unknown_tier_stats", unknown_tier_stats)?;
-        }
-        if let Some(proof) = self.tier_accounting_proof.as_ref() {
-            state.serialize_entry("tier_accounting_proof", proof)?;
-        }
        state.end()
    }
 }

 impl DataUsageEntry {
-    fn has_local_usage(&self) -> bool {
-        self.size != 0
-            || self.objects != 0
-            || self.versions != 0
-            || self.delete_markers != 0
-            || self.failed_objects != 0
-            || self.obj_sizes.0.iter().any(|value| *value != 0)
-            || self.obj_versions.0.iter().any(|value| *value != 0)
-            || self.replication_stats.as_ref().is_some_and(|stats| !stats.is_empty())
-            || self
-                .all_tier_stats
-                .as_ref()
-                .is_some_and(|stats| stats.tiers.values().any(|tier| !tier.is_empty()))
-            || self.unknown_tier_stats.as_ref().is_some_and(|stats| !stats.is_empty())
-    }
-
    pub fn add_child(&mut self, hash: &DataUsageHash) {
        if self.children.contains(&hash.key()) {
            return;
@@ -1131,8 +716,6 @@ impl DataUsageEntry {
    }

    pub fn merge(&mut self, other: &DataUsageEntry) {
-        let self_had_local_usage = self.has_local_usage();
-        let other_had_local_usage = other.has_local_usage();
        self.objects += other.objects;
        self.versions += other.versions;
        self.delete_markers += other.delete_markers;
@@ -1161,29 +744,6 @@ impl DataUsageEntry {
        if let Some(o_tiers) = other.all_tier_stats.as_ref().filter(|tiers| !tiers.is_empty()) {
            self.all_tier_stats.get_or_insert_with(AllTierStats::new).merge(o_tiers);
        }
-        if let Some(other_unknown) = other.unknown_tier_stats.as_ref() {
-            self.unknown_tier_stats
-                .get_or_insert_with(UnknownTierStats::default)
-                .merge(other_unknown);
-        }
-
-        self.tier_accounting_proof = match (self.tier_accounting_proof, other.tier_accounting_proof) {
-            (Some(mut left), Some(right)) => {
-                left.saturating_add(right);
-                Some(left)
-            }
-            (None, Some(right)) if !self_had_local_usage => Some(right),
-            (Some(left), None) if !other_had_local_usage => Some(left),
-            (None, None) => None,
-            _ => None,
-        };
-        // A saturated unknown-tier counter invalidates conservation evidence;
-        // never let an otherwise valid proof hide that loss of precision.
-        if self.unknown_tier_stats.as_ref().is_some_and(|stats| stats.counter_overflowed)
-            && let Some(proof) = self.tier_accounting_proof.as_mut()
-        {
-            proof.overflowed = true;
-        }

        self.obj_sizes.merge_from(&other.obj_sizes);
        self.obj_versions.merge_from(&other.obj_versions);
@@ -1197,15 +757,6 @@ impl DataUsageEntry {
        self.all_tier_stats.get_or_insert_with(AllTierStats::new).add_sizes(tiers);
    }

-    pub fn add_unknown_tier_stats(&mut self, stats: &UnknownTierStats) {
-        if stats.is_empty() {
-            return;
-        }
-        self.unknown_tier_stats
-            .get_or_insert_with(UnknownTierStats::default)
-            .merge(stats);
-    }
-
    pub fn checked_merge(&mut self, other: &DataUsageEntry) -> bool {
        let scalar_counts_fit = self.objects.checked_add(other.objects).is_some()
            && self.versions.checked_add(other.versions).is_some()
@@ -1269,21 +820,8 @@ impl DataUsageEntry {
            (_, None) | (None, Some(_)) => true,
            (Some(left), Some(right)) => left.fits_merge(right),
        };
-        let unknown_tier_stats_fit = match (&self.unknown_tier_stats, &other.unknown_tier_stats) {
-            (None, None) => true,
-            (Some(left), None) => !left.counter_overflowed,
-            (None, Some(right)) => !right.counter_overflowed,
-            (Some(left), Some(right)) => left.fits_add(right),
-        };

-        let proof_fit = match (self.tier_accounting_proof, other.tier_accounting_proof) {
-            (Some(left), Some(right)) => left.checked_add(right).is_some(),
-            (Some(proof), None) | (None, Some(proof)) => !proof.overflowed,
-            (None, None) => true,
-        };
-
-        if !scalar_counts_fit || !histograms_fit || !replication_fits || !tier_stats_fit || !unknown_tier_stats_fit || !proof_fit
-        {
+        if !scalar_counts_fit || !histograms_fit || !replication_fits || !tier_stats_fit {
            return false;
        }
        self.merge(other);
@@ -1801,7 +1339,6 @@ impl DataUsageCache {
            delete_markers_total_count: flat.delete_markers as u64,
            objects_total_size: flat.size as u64,
            tier_stats: flat.all_tier_stats.filter(|tiers| !tiers.is_empty()),
-            unknown_tier_stats: flat.unknown_tier_stats.filter(|stats| !stats.is_empty()),
            buckets_count: u64::try_from(buckets.len()).unwrap_or(u64::MAX),
            buckets_usage,
            usage_snapshot_complete: self.info.snapshot_complete,
@@ -2229,20 +1766,6 @@ impl SizeSummary {
        self.replica_count = self.replica_count.saturating_add(other.replica_count);
        self.pending_count = self.pending_count.saturating_add(other.pending_count);
        self.failed_count = self.failed_count.saturating_add(other.failed_count);
-        self.unknown_tier_stats.merge(&other.unknown_tier_stats);
-        self.tier_accounting_proof.saturating_add(other.tier_accounting_proof);
-        if self.unknown_tier_stats.counter_overflowed {
-            self.tier_accounting_proof.overflowed = true;
-        }
-
-        // A disk/bucket aggregate is assembled from many object summaries.
-        // Keep the per-tier dimension in lockstep with the scalar counters;
-        // dropping this map here would recreate the original silent-loss bug
-        // at the cross-disk merge boundary.
-        for (tier, stats) in &other.tier_stats {
-            let entry = self.tier_stats.entry(tier.clone()).or_default();
-            *entry = entry.add(stats);
-        }

        // Merge replication target stats
        for (target, stats) in &other.repl_target_stats {
@@ -2355,59 +1878,6 @@ mod tests {
        );
    }

-    #[test]
-    fn retired_tier_stats_fold_into_fixed_unknown_bucket() {
-        let mut stats = AllTierStats::default();
-        stats.tiers.insert(
-            "RETIRED".to_string(),
-            TierStats {
-                total_size: 9,
-                num_versions: 2,
-                num_objects: 1,
-            },
-        );
-        stats.tiers.insert(
-            "WARM".to_string(),
-            TierStats {
-                total_size: 4,
-                num_versions: 1,
-                num_objects: 1,
-            },
-        );
-
-        stats.fold_unknown_tiers(["WARM"]);
-
-        assert!(!stats.tiers.contains_key("RETIRED"));
-        assert_eq!(stats.tiers.get("WARM").map(|v| v.total_size), Some(4));
-        assert_eq!(stats.tiers.get(UNKNOWN_TIER).map(|v| v.total_size), Some(9));
-    }
-
-    #[test]
-    fn unknown_tier_stats_deserialization_keeps_diagnostics_bounded() {
-        #[derive(Serialize)]
-        struct RawUnknownTierStats {
-            unknown_bytes: u64,
-            diagnostics: Vec<String>,
-            diagnostics_dropped: u64,
-        }
-
-        let mut diagnostics = vec!["tier-hash:0123456789abcdef".to_string(); UNKNOWN_TIER_DIAGNOSTIC_ENTRY_CAP + 8];
-        diagnostics.push("raw-tier-name-that-must-not-be-exposed".to_string());
-        diagnostics.push("x".repeat(UNKNOWN_TIER_DIAGNOSTIC_BYTE_CAP + 1));
-        let encoded = rmp_serde::to_vec_named(&RawUnknownTierStats {
-            unknown_bytes: 7,
-            diagnostics,
-            diagnostics_dropped: 3,
-        })
-        .expect("unknown tier stats should encode");
-        let decoded: UnknownTierStats = rmp_serde::from_slice(&encoded).expect("unknown tier stats should decode");
-
-        assert_eq!(decoded.unknown_bytes, 7);
-        assert_eq!(decoded.diagnostics.len(), 1);
-        assert!(decoded.diagnostics_dropped >= 3);
-        assert!(decoded.diagnostics.iter().all(|entry| is_redacted_tier_diagnostic(entry)));
-    }
-
    #[test]
    fn checked_merge_rejects_overflowing_tier_totals() {
        let mut left = tier_entry(
@@ -2431,57 +1901,6 @@ mod tests {
        assert_eq!(left.all_tier_stats.expect("left is untouched").tiers["WARM"].total_size, u64::MAX);
    }

-    #[test]
-    fn checked_merge_rejects_unknown_counter_overflow_on_either_side() {
-        let overflowed = DataUsageEntry {
-            unknown_tier_stats: Some(UnknownTierStats {
-                counter_overflowed: true,
-                ..Default::default()
-            }),
-            tier_accounting_proof: Some(TierAccountingProof {
-                logical_total: 1,
-                logical_known: 1,
-                ..Default::default()
-            }),
-            ..Default::default()
-        };
-        let mut left = DataUsageEntry::default();
-        assert!(!left.checked_merge(&overflowed));
-
-        let mut left = overflowed.clone();
-        assert!(!left.checked_merge(&DataUsageEntry::default()));
-    }
-
-    #[test]
-    fn checked_merge_rejects_one_sided_overflowed_proof_without_mutation() {
-        let mut left = DataUsageEntry {
-            size: 1,
-            tier_accounting_proof: Some(TierAccountingProof {
-                logical_total: 1,
-                logical_known: 1,
-                overflowed: true,
-                ..Default::default()
-            }),
-            ..Default::default()
-        };
-        let legacy = DataUsageEntry {
-            size: 2,
-            ..Default::default()
-        };
-
-        assert!(!left.checked_merge(&legacy));
-        assert_eq!(left.size, 1);
-        assert_eq!(
-            left.tier_accounting_proof,
-            Some(TierAccountingProof {
-                logical_total: 1,
-                logical_known: 1,
-                overflowed: true,
-                ..Default::default()
-            })
-        );
-    }
-
    /// Entry shape released before per-tier accounting, using the derived
    /// (array) encoding those writers produced.
    #[derive(Serialize, Deserialize)]
@@ -2521,72 +1940,6 @@ mod tests {
        assert_eq!(legacy.objects, 0);
    }

-    #[test]
-    fn tier_accounting_proof_is_optional_and_map_encoded() {
-        let entry = DataUsageEntry {
-            tier_accounting_proof: Some(TierAccountingProof {
-                logical_total: 11,
-                logical_known: 11,
-                physical_total: 7,
-                physical_known: 7,
-                ..Default::default()
-            }),
-            ..Default::default()
-        };
-        let encoded = rmp_serde::to_vec(&entry).expect("proof-bearing entry should encode");
-        let decoded: DataUsageEntry = rmp_serde::from_slice(&encoded).expect("proof-bearing entry should decode");
-        assert_eq!(decoded.tier_accounting_proof, entry.tier_accounting_proof);
-
-        let legacy = LegacyEntry {
-            children: DataUsageHashMap::default(),
-            size: 12,
-            objects: 3,
-            versions: 4,
-            delete_markers: 1,
-            obj_sizes: SizeHistogram::default(),
-            obj_versions: VersionsHistogram::default(),
-            replication_stats: None,
-            compacted: false,
-            failed_objects: 2,
-        };
-        let legacy_bytes = rmp_serde::to_vec(&legacy).expect("legacy entry should encode");
-        let decoded: DataUsageEntry = rmp_serde::from_slice(&legacy_bytes).expect("legacy entry should decode");
-        assert!(decoded.tier_accounting_proof.is_none());
-    }
-
-    #[test]
-    fn empty_entry_merge_preserves_accounting_proof() {
-        let mut entry = DataUsageEntry {
-            tier_accounting_proof: Some(TierAccountingProof {
-                logical_total: 7,
-                logical_known: 7,
-                physical_total: 7,
-                physical_known: 7,
-                ..Default::default()
-            }),
-            ..Default::default()
-        };
-        entry.merge(&DataUsageEntry::default());
-        assert!(entry.tier_accounting_proof.is_some());
-
-        let mut empty = DataUsageEntry::default();
-        empty.merge(&entry);
-        assert_eq!(empty.tier_accounting_proof, entry.tier_accounting_proof);
-    }
-
-    #[test]
-    fn unknown_counter_overflow_is_not_empty_and_survives_roundtrip() {
-        let stats = UnknownTierStats {
-            counter_overflowed: true,
-            ..Default::default()
-        };
-        assert!(!stats.is_empty());
-        let encoded = rmp_serde::to_vec_named(&stats).expect("overflow marker should encode");
-        let decoded: UnknownTierStats = rmp_serde::from_slice(&encoded).expect("overflow marker should decode");
-        assert!(decoded.counter_overflowed);
-        assert!(!decoded.is_empty());
-    }
-
    #[test]
    fn legacy_array_encoded_entries_still_load() {
        let legacy = LegacyEntry {
@@ -3355,32 +2708,6 @@ mod tests {
        );
    }

-    #[test]
-    fn test_dui_filters_empty_unknown_tier_usage_from_the_flattened_tree() {
-        let root_hash = hash_path("root");
-        let bucket_hash = hash_path("bucket-a");
-        let mut cache = DataUsageCache {
-            info: DataUsageCacheInfo {
-                name: "root".to_string(),
-                ..Default::default()
-            },
-            ..Default::default()
-        };
-        cache.replace_hashed(&root_hash, &None, &DataUsageEntry::default());
-
-        let child = DataUsageEntry {
-            objects: 1,
-            unknown_tier_stats: Some(UnknownTierStats::default()),
-            ..Default::default()
-        };
-        cache.replace_hashed(&bucket_hash, &Some(root_hash), &child);
-
-        let info = cache.dui("root", &["bucket-a".to_string()]);
-
-        assert_eq!(info.objects_total_count, 1);
-        assert!(info.unknown_tier_stats.is_none());
-    }
-
    #[test]
    fn test_data_usage_entry_merge_preserves_replication_targets() {
        let mut base = DataUsageEntry {
@@ -456,13 +456,11 @@ pub mod rpc {
        ScannerBucketListing, ScannerPeerActivity, TONIC_RPC_PREFIX, TonicInterceptor, build_put_file_auth_trailer,
        check_and_record_signed_rpc_nonce, gen_signature_headers, gen_tonic_replay_scope_headers, gen_tonic_signature_headers,
        gen_tonic_signature_interceptor, node_service_time_out_client, node_service_time_out_client_no_auth,
-        normalize_tonic_rpc_audience, set_tonic_canonical_body_digest, sign_ns_scanner_capability,
-        sign_ns_scanner_capability_with_tier_registry_generation, sign_put_file_capability, sign_tonic_rpc_response_proof,
-        tonic_boot_epoch_challenge, tonic_boot_epoch_response_headers, tonic_rpc_auth_failure_reason,
-        verify_ns_scanner_capability, verify_ns_scanner_capability_with_tier_registry_generation, verify_put_file_auth_trailer,
-        verify_put_file_capability, verify_rpc_signature, verify_tonic_boot_epoch_response, verify_tonic_canonical_body_digest,
-        verify_tonic_mutation_body_digest, verify_tonic_rpc_response_proof, verify_tonic_rpc_signature,
-        verify_tonic_rpc_signature_with_bootstrap,
+        normalize_tonic_rpc_audience, set_tonic_canonical_body_digest, sign_ns_scanner_capability, sign_put_file_capability,
+        sign_tonic_rpc_response_proof, tonic_boot_epoch_challenge, tonic_boot_epoch_response_headers,
+        tonic_rpc_auth_failure_reason, verify_put_file_auth_trailer, verify_put_file_capability, verify_rpc_signature,
+        verify_tonic_boot_epoch_response, verify_tonic_canonical_body_digest, verify_tonic_mutation_body_digest,
+        verify_tonic_rpc_response_proof, verify_tonic_rpc_signature, verify_tonic_rpc_signature_with_bootstrap,
    };
 }

@@ -94,7 +94,6 @@ const REPLAY_CACHE_AUTO_MEMORY_PERCENT: u64 = 13;
 const REPLAY_CACHE_AUTO_RPC_RPS_PER_CPU: usize = 4096;
 const REPLAY_CACHE_AUTO_MAX_CAPACITY: usize = 33_554_432;
 const NS_SCANNER_CAPABILITY_AUTH_DOMAIN: &[u8] = b"rustfs-ns-scanner-capability-v3";
-const NS_SCANNER_TIER_REGISTRY_GENERATION_AUTH_DOMAIN: &[u8] = b"rustfs-ns-scanner-tier-registry-generation-v1";
 pub const TONIC_RPC_PREFIX: &str = "/node_service.NodeService";
 static INTERNODE_RPC_SIGNATURE_STRICT: LazyLock<bool> = LazyLock::new(|| {
    get_env_bool(
@@ -637,79 +636,40 @@ pub fn verify_put_file_capability(challenge: Uuid, server_epoch: Uuid, version:
        .map_err(|_| std::io::Error::new(std::io::ErrorKind::PermissionDenied, "Invalid put_file capability proof"))
 }

-fn update_ns_scanner_capability_mac(
-    mac: &mut HmacSha256,
-    challenge: Uuid,
-    server_epoch: Uuid,
-    supports_tier_registry_generation: bool,
-) {
+fn update_ns_scanner_capability_mac(mac: &mut HmacSha256, challenge: Uuid, server_epoch: Uuid) {
    mac.update(NS_SCANNER_CAPABILITY_AUTH_DOMAIN);
    mac.update(&NS_SCANNER_PROTOCOL_VERSION.to_be_bytes());
    mac.update(challenge.as_bytes());
    mac.update(server_epoch.as_bytes());
-    if supports_tier_registry_generation {
-        // The optional response capability is part of the authenticated
-        // scope. A proxy cannot turn an old/unsupported peer into a worker
-        // that receives generation-fenced scanner work.
-        mac.update(NS_SCANNER_TIER_REGISTRY_GENERATION_AUTH_DOMAIN);
-    }
 }

-fn generate_ns_scanner_capability_proof(
-    secret: &str,
-    challenge: Uuid,
-    server_epoch: Uuid,
-    supports_tier_registry_generation: bool,
-) -> std::io::Result<Vec<u8>> {
+fn generate_ns_scanner_capability_proof(secret: &str, challenge: Uuid, server_epoch: Uuid) -> std::io::Result<Vec<u8>> {
    if challenge.is_nil() || server_epoch.is_nil() {
        return Err(std::io::Error::other("Invalid namespace scanner capability scope"));
    }
    let mut mac =
        <HmacSha256 as KeyInit>::new_from_slice(secret.as_bytes()).map_err(|_| std::io::Error::other("Invalid RPC HMAC key"))?;
-    update_ns_scanner_capability_mac(&mut mac, challenge, server_epoch, supports_tier_registry_generation);
+    update_ns_scanner_capability_mac(&mut mac, challenge, server_epoch);
    Ok(mac.finalize().into_bytes().to_vec())
 }

-fn verify_ns_scanner_capability_proof(
-    secret: &str,
-    challenge: Uuid,
-    server_epoch: Uuid,
-    proof: &[u8],
-    supports_tier_registry_generation: bool,
-) -> std::io::Result<()> {
+fn verify_ns_scanner_capability_proof(secret: &str, challenge: Uuid, server_epoch: Uuid, proof: &[u8]) -> std::io::Result<()> {
    if challenge.is_nil() || server_epoch.is_nil() {
        return Err(std::io::Error::other("Invalid namespace scanner capability scope"));
    }
    let mut mac =
        <HmacSha256 as KeyInit>::new_from_slice(secret.as_bytes()).map_err(|_| std::io::Error::other("Invalid RPC HMAC key"))?;
-    update_ns_scanner_capability_mac(&mut mac, challenge, server_epoch, supports_tier_registry_generation);
+    update_ns_scanner_capability_mac(&mut mac, challenge, server_epoch);
    mac.verify_slice(proof)
        .map_err(|_| std::io::Error::new(std::io::ErrorKind::PermissionDenied, "Invalid namespace scanner capability proof"))
 }

 pub fn sign_ns_scanner_capability(challenge: Uuid, server_epoch: Uuid) -> std::io::Result<Vec<u8>> {
-    sign_ns_scanner_capability_with_tier_registry_generation(challenge, server_epoch, false)
+    generate_ns_scanner_capability_proof(&get_shared_secret()?, challenge, server_epoch)
 }

 pub fn verify_ns_scanner_capability(challenge: Uuid, server_epoch: Uuid, proof: &[u8]) -> std::io::Result<()> {
-    verify_ns_scanner_capability_with_tier_registry_generation(challenge, server_epoch, proof, false)
-}
-
-pub fn sign_ns_scanner_capability_with_tier_registry_generation(
-    challenge: Uuid,
-    server_epoch: Uuid,
-    supports_tier_registry_generation: bool,
-) -> std::io::Result<Vec<u8>> {
-    generate_ns_scanner_capability_proof(&get_shared_secret()?, challenge, server_epoch, supports_tier_registry_generation)
-}
-
-pub fn verify_ns_scanner_capability_with_tier_registry_generation(
-    challenge: Uuid,
-    server_epoch: Uuid,
-    proof: &[u8],
-    supports_tier_registry_generation: bool,
-) -> std::io::Result<()> {
-    verify_ns_scanner_capability_proof(&get_shared_secret()?, challenge, server_epoch, proof, supports_tier_registry_generation)
+    verify_ns_scanner_capability_proof(&get_shared_secret()?, challenge, server_epoch, proof)
 }

 #[derive(Clone, Copy)]
@@ -1749,28 +1709,13 @@ mod tests {
        let secret = "test-scanner-capability-secret";
        let challenge = Uuid::new_v4();
        let server_epoch = Uuid::new_v4();
-        let proof = generate_ns_scanner_capability_proof(secret, challenge, server_epoch, false)
-            .expect("capability proof should be generated");
+        let proof =
+            generate_ns_scanner_capability_proof(secret, challenge, server_epoch).expect("capability proof should be generated");

-        assert!(verify_ns_scanner_capability_proof(secret, challenge, server_epoch, &proof, false).is_ok());
-        assert!(verify_ns_scanner_capability_proof(secret, Uuid::new_v4(), server_epoch, &proof, false).is_err());
-        assert!(verify_ns_scanner_capability_proof(secret, challenge, Uuid::new_v4(), &proof, false).is_err());
-        assert!(verify_ns_scanner_capability_proof("different-secret", challenge, server_epoch, &proof, false).is_err());
-    }
-
-    #[test]
-    fn namespace_scanner_capability_proof_binds_tier_registry_generation_support() {
-        let secret = "test-scanner-capability-secret";
-        let challenge = Uuid::new_v4();
-        let server_epoch = Uuid::new_v4();
-        let proof = generate_ns_scanner_capability_proof(secret, challenge, server_epoch, true)
-            .expect("generation capability proof should be generated");
-
-        assert!(verify_ns_scanner_capability_proof(secret, challenge, server_epoch, &proof, true).is_ok());
-        assert!(verify_ns_scanner_capability_proof(secret, challenge, server_epoch, &proof, false).is_err());
-        let legacy = generate_ns_scanner_capability_proof(secret, challenge, server_epoch, false)
-            .expect("legacy capability proof should be generated");
-        assert!(verify_ns_scanner_capability_proof(secret, challenge, server_epoch, &legacy, true).is_err());
+        assert!(verify_ns_scanner_capability_proof(secret, challenge, server_epoch, &proof).is_ok());
+        assert!(verify_ns_scanner_capability_proof(secret, Uuid::new_v4(), server_epoch, &proof).is_err());
+        assert!(verify_ns_scanner_capability_proof(secret, challenge, Uuid::new_v4(), &proof).is_err());
+        assert!(verify_ns_scanner_capability_proof("different-secret", challenge, server_epoch, &proof).is_err());
    }

    /// Security regression for GHSA-r5qv-rc46-hv8q (internode RPC fail-closed,
@@ -13,18 +13,17 @@
 // limitations under the License.

 use crate::cluster::rpc::{
-    build_auth_headers, build_put_file_auth_trailer, verify_ns_scanner_capability_with_tier_registry_generation,
-    verify_put_file_capability,
+    build_auth_headers, build_put_file_auth_trailer, verify_ns_scanner_capability, verify_put_file_capability,
 };
 use crate::disk::error::{Error, Result};
 use crate::disk::{FileReader, FileWriter};
 use crate::storage_api_contracts::internode::{
    NS_SCANNER_BODY_SHA256_QUERY, NS_SCANNER_CAPABILITY_CHALLENGE_QUERY, NS_SCANNER_CYCLE_QUERY, NS_SCANNER_LEADER_EPOCH_QUERY,
    NS_SCANNER_PROTOCOL_VERSION, NS_SCANNER_PROTOCOL_VERSION_QUERY, NS_SCANNER_REQUEST_ID_QUERY, NS_SCANNER_SERVER_EPOCH_QUERY,
-    NS_SCANNER_SESSION_ID_QUERY, NS_SCANNER_SESSION_SEQUENCE_QUERY, NS_SCANNER_TIER_REGISTRY_GENERATION_QUERY,
-    NsScannerCapabilityResponse, PUT_FILE_AUTH_QUERY, PUT_FILE_AUTH_V1, PUT_FILE_CAPABILITY_CHALLENGE_QUERY,
-    PUT_FILE_CAPABILITY_QUERY, PUT_FILE_CAPABILITY_VERSION, PUT_FILE_NONCE_QUERY, PUT_FILE_SERVER_EPOCH_QUERY,
-    PutFileCapabilityResponse, WALK_DIR_BODY_SHA256_QUERY, WALK_DIR_STREAM_COMPLETION_QUERY, WALK_DIR_STREAM_COMPLETION_V1,
+    NS_SCANNER_SESSION_ID_QUERY, NS_SCANNER_SESSION_SEQUENCE_QUERY, NsScannerCapabilityResponse, PUT_FILE_AUTH_QUERY,
+    PUT_FILE_AUTH_V1, PUT_FILE_CAPABILITY_CHALLENGE_QUERY, PUT_FILE_CAPABILITY_QUERY, PUT_FILE_CAPABILITY_VERSION,
+    PUT_FILE_NONCE_QUERY, PUT_FILE_SERVER_EPOCH_QUERY, PutFileCapabilityResponse, WALK_DIR_BODY_SHA256_QUERY,
+    WALK_DIR_STREAM_COMPLETION_QUERY, WALK_DIR_STREAM_COMPLETION_V1,
 };
 use async_trait::async_trait;
 use http::{HeaderMap, HeaderValue, Method, header::CONTENT_TYPE};
@@ -138,12 +137,6 @@ fn put_file_capability_status_is_legacy(status: u16) -> bool {
    status == 404
 }

-fn ns_scanner_capability_error_allows_legacy(error: &Error) -> bool {
-    [400, 404, 405, 426]
-        .into_iter()
-        .any(|status| error.is_internode_http_status(status))
-}
-
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
 #[allow(
    dead_code,
@@ -227,7 +220,6 @@ pub struct NsScannerStreamRequest {
 #[derive(Debug, Clone)]
 pub struct NsScannerCapabilityRequest {
    pub endpoint: String,
-    pub supports_tier_registry_generation: bool,
 }

 /// Data-plane stream opener used by `RemoteDisk`.
@@ -260,15 +252,6 @@ pub trait InternodeDataTransport: Send + Sync + std::fmt::Debug {
    async fn probe_ns_scanner(&self, _request: NsScannerCapabilityRequest) -> Result<Uuid> {
        Err(Error::MethodNotAllowed)
    }
-    async fn probe_ns_scanner_capability(&self, request: NsScannerCapabilityRequest) -> Result<NsScannerCapabilityResponse> {
-        let server_epoch = self.probe_ns_scanner(request).await?;
-        Ok(NsScannerCapabilityResponse {
-            version: NS_SCANNER_PROTOCOL_VERSION,
-            server_epoch,
-            proof: Vec::new(),
-            supports_tier_registry_generation: None,
-        })
-    }
    // 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.
@@ -352,44 +335,27 @@ impl InternodeDataTransport for TcpHttpInternodeDataTransport {
    }

    async fn probe_ns_scanner(&self, request: NsScannerCapabilityRequest) -> Result<Uuid> {
-        Ok(self.probe_ns_scanner_capability(request).await?.server_epoch)
-    }
-
-    async fn probe_ns_scanner_capability(&self, request: NsScannerCapabilityRequest) -> Result<NsScannerCapabilityResponse> {
-        if request.supports_tier_registry_generation {
-            return match self.probe_ns_scanner_capability_once(&request).await {
-                Ok(response) => Ok(response),
-                Err(marked_error) if ns_scanner_capability_error_allows_legacy(&marked_error) => {
-                    // A v3 peer may reject the additive query marker, ignore
-                    // it, or return its legacy proof. Retry once without the
-                    // marker and only downgrade after that legacy response is
-                    // authenticated; an unverified epoch is never trusted.
-                    let legacy_request = NsScannerCapabilityRequest {
-                        endpoint: request.endpoint.clone(),
-                        supports_tier_registry_generation: false,
-                    };
-                    match self.probe_ns_scanner_capability_once(&legacy_request).await {
-                        Ok(mut response) => {
-                            response.supports_tier_registry_generation = None;
-                            Ok(response)
-                        }
-                        Err(legacy_error) if ns_scanner_capability_error_allows_legacy(&legacy_error) => {
-                            // Some old deployments expose only the legacy
-                            // protocol response (or advertise 426). Treat
-                            // the pair as an explicit unsupported result so
-                            // the scanner can use its coordinator fallback.
-                            Err(Error::MethodNotAllowed)
-                        }
-                        Err(_) => Err(marked_error),
-                    }
-                }
-                // A server failure, network failure, or authentication error
-                // is not evidence of an old parser. Do not issue an
-                // unauthenticated legacy probe or silently downgrade.
-                Err(marked_error) => Err(marked_error),
-            };
+        let challenge = Uuid::new_v4();
+        let url = build_ns_scanner_capability_url(&request, challenge);
+        let mut headers = msgpack_headers();
+        build_auth_headers(&url, &Method::GET, &mut headers)?;
+        let reader = HttpReader::new(url, Method::GET, headers, None).await?;
+        let mut body = Vec::new();
+        reader
+            .take(u64::try_from(NS_SCANNER_MAX_CAPABILITY_RESPONSE_SIZE + 1).unwrap_or(u64::MAX))
+            .read_to_end(&mut body)
+            .await?;
+        if body.is_empty() || body.len() > NS_SCANNER_MAX_CAPABILITY_RESPONSE_SIZE {
+            return Err(Error::other("invalid remote namespace scanner capability response size"));
        }
-        self.probe_ns_scanner_capability_once(&request).await
+        let response: NsScannerCapabilityResponse =
+            rmp_serde::from_slice(&body).map_err(|_| Error::other("invalid remote namespace scanner capability response"))?;
+        if response.version != NS_SCANNER_PROTOCOL_VERSION || response.server_epoch.is_nil() {
+            return Err(Error::other("incompatible remote namespace scanner capability response"));
+        }
+        verify_ns_scanner_capability(challenge, response.server_epoch, &response.proof)
+            .map_err(|err| Error::other(format!("remote namespace scanner capability authentication failed: {err}")))?;
+        Ok(response.server_epoch)
    }

    fn name(&self) -> &'static str {
@@ -402,53 +368,6 @@ impl InternodeDataTransport for TcpHttpInternodeDataTransport {
 }

 impl TcpHttpInternodeDataTransport {
-    async fn probe_ns_scanner_capability_once(
-        &self,
-        request: &NsScannerCapabilityRequest,
-    ) -> Result<NsScannerCapabilityResponse> {
-        let challenge = Uuid::new_v4();
-        let url = build_ns_scanner_capability_url(request, challenge);
-        let mut headers = msgpack_headers();
-        build_auth_headers(&url, &Method::GET, &mut headers)?;
-        let reader = HttpReader::new(url, Method::GET, headers, None).await?;
-        let mut body = Vec::new();
-        reader
-            .take(u64::try_from(NS_SCANNER_MAX_CAPABILITY_RESPONSE_SIZE + 1).unwrap_or(u64::MAX))
-            .read_to_end(&mut body)
-            .await?;
-        if body.is_empty() || body.len() > NS_SCANNER_MAX_CAPABILITY_RESPONSE_SIZE {
-            return Err(Error::other("invalid remote namespace scanner capability response size"));
-        }
-        let mut response: NsScannerCapabilityResponse =
-            rmp_serde::from_slice(&body).map_err(|_| Error::other("invalid remote namespace scanner capability response"))?;
-        if response.version != NS_SCANNER_PROTOCOL_VERSION || response.server_epoch.is_nil() {
-            return Err(Error::other("incompatible remote namespace scanner capability response"));
-        }
-        if let Err(err) = verify_ns_scanner_capability_with_tier_registry_generation(
-            challenge,
-            response.server_epoch,
-            &response.proof,
-            request.supports_tier_registry_generation,
-        ) {
-            // A permissive older peer can ignore the additive marker and
-            // return a valid legacy-scope proof with HTTP 200. Accept that
-            // response only after independently authenticating the legacy
-            // scope; all other verification failures remain fail-closed.
-            if request.supports_tier_registry_generation && ns_scanner_capability_legacy_proof_is_valid(challenge, &response) {
-                response.supports_tier_registry_generation = None;
-                return Ok(response);
-            }
-            return Err(Error::other(format!("remote namespace scanner capability authentication failed: {err}")));
-        }
-        // The proof authenticates the requested capability scope, not the
-        // optional response field. Derive the client-facing bit from that
-        // verified scope so an intermediary cannot strip or rewrite the field
-        // and force a silent downgrade after a successful generation-bound
-        // handshake.
-        normalize_ns_scanner_capability_response(&mut response, request.supports_tier_registry_generation);
-        Ok(response)
-    }
-
    async fn put_file_auth_capability(&self, endpoint: &str) -> Result<Option<Uuid>> {
        resolve_put_file_auth_capability(endpoint, || async {
            tokio::time::timeout(PUT_FILE_CAPABILITY_PROBE_TIMEOUT, self.probe_put_file_auth(endpoint))
@@ -730,14 +649,6 @@ fn build_walk_dir_url(request: &WalkDirStreamRequest) -> String {
    )
 }

-fn normalize_ns_scanner_capability_response(response: &mut NsScannerCapabilityResponse, requested_generation_support: bool) {
-    response.supports_tier_registry_generation = requested_generation_support.then_some(true);
-}
-
-fn ns_scanner_capability_legacy_proof_is_valid(challenge: Uuid, response: &NsScannerCapabilityResponse) -> bool {
-    verify_ns_scanner_capability_with_tier_registry_generation(challenge, response.server_epoch, &response.proof, false).is_ok()
-}
-
 fn build_ns_scanner_url(request: &NsScannerStreamRequest) -> String {
    let body_sha256 = hex_simd::encode_to_string(Sha256::digest(&request.body), hex_simd::AsciiCase::Lower);
    format!(
@@ -764,18 +675,13 @@ fn build_ns_scanner_url(request: &NsScannerStreamRequest) -> String {

 fn build_ns_scanner_capability_url(request: &NsScannerCapabilityRequest, challenge: Uuid) -> String {
    format!(
-        "{}{}?{}={}&{}={}{}",
+        "{}{}?{}={}&{}={}",
        request.endpoint,
        NS_SCANNER_PATH,
        NS_SCANNER_PROTOCOL_VERSION_QUERY,
        NS_SCANNER_PROTOCOL_VERSION,
        NS_SCANNER_CAPABILITY_CHALLENGE_QUERY,
-        challenge,
-        if request.supports_tier_registry_generation {
-            format!("&{}=true", NS_SCANNER_TIER_REGISTRY_GENERATION_QUERY)
-        } else {
-            String::new()
-        }
+        challenge
    )
 }

@@ -888,7 +794,6 @@ mod tests {
        let probe_err = transport
            .probe_ns_scanner(NsScannerCapabilityRequest {
                endpoint: "http://node1:9000".to_string(),
-                supports_tier_registry_generation: false,
            })
            .await
            .expect_err("legacy transport should report namespace scanner as unsupported");
@@ -1482,7 +1387,6 @@ mod tests {
        let url = build_ns_scanner_capability_url(
            &NsScannerCapabilityRequest {
                endpoint: "http://node1:9000".to_string(),
-                supports_tier_registry_generation: false,
            },
            challenge,
        );
@@ -1495,85 +1399,6 @@ mod tests {
        );
    }

-    #[test]
-    fn ns_scanner_capability_url_marks_generation_support_only_when_requested() {
-        let challenge = Uuid::new_v4();
-        let url = build_ns_scanner_capability_url(
-            &NsScannerCapabilityRequest {
-                endpoint: "http://node1:9000".to_string(),
-                supports_tier_registry_generation: true,
-            },
-            challenge,
-        );
-
-        assert!(url.contains(&format!("&{}=true", NS_SCANNER_TIER_REGISTRY_GENERATION_QUERY)));
-    }
-
-    #[test]
-    fn ns_scanner_capability_legacy_fallback_requires_explicit_compatibility_status() {
-        for status in [400, 404, 405, 426] {
-            let error = Error::from(rustfs_rio::new_test_internode_http_io_error(
-                rustfs_rio::InternodeHttpErrorKind::HttpStatus(http::StatusCode::from_u16(status).expect("test status")),
-            ));
-            assert!(
-                ns_scanner_capability_error_allows_legacy(&error),
-                "status {status} should permit legacy retry"
-            );
-        }
-
-        let marked_server_error = Error::from(rustfs_rio::new_test_internode_http_io_error(
-            rustfs_rio::InternodeHttpErrorKind::HttpStatus(http::StatusCode::INTERNAL_SERVER_ERROR),
-        ));
-        let network_error = Error::from(rustfs_rio::new_test_internode_http_io_error(
-            rustfs_rio::InternodeHttpErrorKind::ConnectionRefused,
-        ));
-        let authentication_error = Error::other("remote namespace scanner capability authentication failed");
-        assert!(!ns_scanner_capability_error_allows_legacy(&marked_server_error));
-        assert!(!ns_scanner_capability_error_allows_legacy(&network_error));
-        assert!(!ns_scanner_capability_error_allows_legacy(&authentication_error));
-    }
-
-    #[test]
-    fn authenticated_ns_scanner_capability_ignores_unprotected_response_bit() {
-        let mut response = NsScannerCapabilityResponse {
-            version: NS_SCANNER_PROTOCOL_VERSION,
-            server_epoch: Uuid::new_v4(),
-            proof: Vec::new(),
-            supports_tier_registry_generation: None,
-        };
-
-        normalize_ns_scanner_capability_response(&mut response, true);
-        assert_eq!(response.supports_tier_registry_generation, Some(true));
-
-        response.supports_tier_registry_generation = Some(false);
-        normalize_ns_scanner_capability_response(&mut response, false);
-        assert_eq!(response.supports_tier_registry_generation, None);
-    }
-
-    #[test]
-    fn ns_scanner_capability_accepts_only_authenticated_legacy_scope_after_marker_mismatch() {
-        crate::runtime::sources::ensure_test_rpc_secret();
-        let challenge = Uuid::new_v4();
-        let response = NsScannerCapabilityResponse {
-            version: NS_SCANNER_PROTOCOL_VERSION,
-            server_epoch: Uuid::new_v4(),
-            proof: crate::cluster::rpc::sign_ns_scanner_capability(challenge, Uuid::new_v4())
-                .expect("placeholder proof should be generated"),
-            supports_tier_registry_generation: None,
-        };
-        // A proof bound to a different challenge cannot authorize the legacy
-        // fallback, even though the response has the expected shape.
-        assert!(!ns_scanner_capability_legacy_proof_is_valid(challenge, &response));
-
-        let server_epoch = response.server_epoch;
-        let valid_response = NsScannerCapabilityResponse {
-            proof: crate::cluster::rpc::sign_ns_scanner_capability(challenge, server_epoch)
-                .expect("legacy proof should be generated"),
-            ..response
-        };
-        assert!(ns_scanner_capability_legacy_proof_is_valid(challenge, &valid_response));
-    }
-
    #[test]
    fn transport_config_defaults_to_tcp_http() {
        let transport = build_internode_data_transport(None).unwrap();
@@ -35,9 +35,8 @@ pub use http_auth::{
    TONIC_RPC_PREFIX, build_auth_headers, build_put_file_auth_trailer, check_and_record_signed_rpc_nonce, gen_signature_headers,
    gen_tonic_replay_scope_headers, gen_tonic_signature_headers, normalize_tonic_rpc_audience, set_tonic_canonical_body_digest,
    set_tonic_mutation_body_digest, set_tonic_rolling_canonical_body_digest, set_tonic_rolling_mutation_body_digest,
-    sign_ns_scanner_capability, sign_ns_scanner_capability_with_tier_registry_generation, sign_put_file_capability,
-    sign_tonic_rpc_response_proof, tonic_boot_epoch_challenge, tonic_boot_epoch_response_headers, tonic_rpc_auth_failure_reason,
-    verify_ns_scanner_capability, verify_ns_scanner_capability_with_tier_registry_generation, verify_put_file_auth_trailer,
+    sign_ns_scanner_capability, sign_put_file_capability, sign_tonic_rpc_response_proof, tonic_boot_epoch_challenge,
+    tonic_boot_epoch_response_headers, tonic_rpc_auth_failure_reason, verify_ns_scanner_capability, verify_put_file_auth_trailer,
    verify_put_file_capability, verify_rpc_signature, verify_tonic_boot_epoch_response, verify_tonic_canonical_body_digest,
    verify_tonic_mutation_body_digest, verify_tonic_rpc_response_proof, verify_tonic_rpc_signature,
    verify_tonic_rpc_signature_with_bootstrap,
@@ -781,16 +781,14 @@ impl RemoteDisk {
        if self.health.is_faulty() {
            return Err(DiskError::FaultyDisk);
        }
-        let probe = self.data_transport.probe_ns_scanner_capability(NsScannerCapabilityRequest {
+        let probe = self.data_transport.probe_ns_scanner(NsScannerCapabilityRequest {
            endpoint: self.endpoint.grid_host(),
-            supports_tier_registry_generation: true,
        });
        let result = timeout(NS_SCANNER_CAPABILITY_PROBE_TIMEOUT, probe)
            .await
            .map_err(|_| DiskError::other("remote namespace scanner capability probe timed out"))?;
        match result {
-            Ok(response) if response.supports_tier_registry_generation == Some(true) => Ok(Some(response.server_epoch)),
-            Ok(_) => Ok(None),
+            Ok(server_epoch) => Ok(Some(server_epoch)),
            // RUSTFS_COMPAT_TODO(ns-scanner-rpc-v3): old peers and legacy transports lack the authenticated startup-epoch handshake. Remove after every supported peer implements namespace scanner protocol v3.
            Err(DiskError::MethodNotAllowed) => Ok(None),
            Err(err)
@@ -4042,21 +4040,10 @@ mod tests {
        NsScannerProbe(NsScannerCapabilityRequest),
    }

-    #[derive(Debug, Clone)]
+    #[derive(Debug, Clone, Default)]
    struct RecordingInternodeDataTransport {
        calls: Arc<StdMutex<Vec<RecordedTransportCall>>>,
        ns_scanner_probe_status: Arc<StdMutex<Option<u16>>>,
-        ns_scanner_generation_support: Arc<StdMutex<Option<bool>>>,
-    }
-
-    impl Default for RecordingInternodeDataTransport {
-        fn default() -> Self {
-            Self {
-                calls: Arc::default(),
-                ns_scanner_probe_status: Arc::default(),
-                ns_scanner_generation_support: Arc::new(StdMutex::new(Some(true))),
-            }
-        }
    }

    #[derive(Clone, Debug)]
@@ -4276,15 +4263,6 @@ mod tests {
            Self {
                calls: Arc::default(),
                ns_scanner_probe_status: Arc::new(StdMutex::new(Some(status))),
-                ns_scanner_generation_support: Arc::new(StdMutex::new(Some(true))),
-            }
-        }
-
-        fn with_ns_scanner_generation_support(support: Option<bool>) -> Self {
-            Self {
-                calls: Arc::default(),
-                ns_scanner_probe_status: Arc::default(),
-                ns_scanner_generation_support: Arc::new(StdMutex::new(support)),
            }
        }

@@ -4967,23 +4945,6 @@ mod tests {
            Ok(Uuid::from_u128(1))
        }

-        async fn probe_ns_scanner_capability(
-            &self,
-            request: NsScannerCapabilityRequest,
-        ) -> Result<crate::storage_api_contracts::internode::NsScannerCapabilityResponse> {
-            let server_epoch = self.probe_ns_scanner(request).await?;
-            let supports_tier_registry_generation = *self
-                .ns_scanner_generation_support
-                .lock()
-                .expect("namespace scanner generation support lock poisoned");
-            Ok(crate::storage_api_contracts::internode::NsScannerCapabilityResponse {
-                version: crate::storage_api_contracts::internode::NS_SCANNER_PROTOCOL_VERSION,
-                server_epoch,
-                proof: Vec::new(),
-                supports_tier_registry_generation,
-            })
-        }
-
        fn name(&self) -> &'static str {
            "recording"
        }
@@ -6796,22 +6757,6 @@ mod tests {
        }
    }

-    #[tokio::test]
-    async fn test_remote_disk_namespace_scanner_capability_falls_back_without_generation_support() {
-        for support in [None, Some(false)] {
-            let transport = RecordingInternodeDataTransport::with_ns_scanner_generation_support(support);
-            let remote_disk = new_remote_disk_with_transport(Arc::new(transport)).await;
-
-            assert_eq!(
-                remote_disk
-                    .ns_scanner_server_epoch()
-                    .await
-                    .expect("missing generation support should be classified as unsupported"),
-                None
-            );
-        }
-    }
-
    #[tokio::test]
    async fn test_remote_disk_namespace_scanner_capability_rejects_legacy_transport() {
        let remote_disk = new_remote_disk_with_transport(Arc::new(RetryingOpenReadInternodeDataTransport::default())).await;
@@ -784,24 +784,6 @@ pub(crate) fn create_deferred_bitrot_reader_with_stripe_handle(
 ///
 /// # Returns
 /// A Result containing the BitrotWriterWrapper or an error
-/// Size hint handed to `DiskAPI::create_file` for a bitrot-wrapped shard.
-///
-/// A known length is grown by one checksum per shard so the on-disk file size
-/// matches what the bitrot writer emits. A negative length is the
-/// unknown-size sentinel (`HashReader::SIZE_PRESERVE_LAYER`, used by SSE and
-/// compression) and must be preserved: `RemoteDisk::create_file` forwards it
-/// in the `put_file_stream` query, and the receiver only treats `size > 0` as
-/// a fixed body length when locating the authenticated trailer. Clamping it
-/// to `0` would claim an empty body and misframe the stream. `0` stays `0`
-/// because a genuinely empty object still means an empty body.
-fn bitrot_create_file_size(length: i64, shard_size: usize, checksum_algo: &HashAlgorithm) -> i64 {
-    if length <= 0 {
-        return length;
-    }
-    let length = length as usize;
-    (length.div_ceil(shard_size) * checksum_algo.size() + length) as i64
-}
-
 pub async fn create_bitrot_writer(
    is_inline_buffer: bool,
    disk: Option<&DiskStore>,
@@ -814,7 +796,12 @@ pub async fn create_bitrot_writer(
    let writer = if is_inline_buffer {
        CustomWriter::new_inline_buffer()
    } else if let Some(disk) = disk {
-        let length = bitrot_create_file_size(length, shard_size, &checksum_algo);
+        let length = if length > 0 {
+            let length = length as usize;
+            (length.div_ceil(shard_size) * checksum_algo.size() + length) as i64
+        } else {
+            0
+        };

        let file = disk.create_file("", volume, path, length).await?;
        #[cfg(feature = "hotpath")]
@@ -833,25 +820,6 @@ mod tests {
    use rustfs_rio::ChunkReader;
    use std::collections::VecDeque;

-    #[test]
-    fn bitrot_create_file_size_grows_known_length_by_checksums() {
-        // 10 bytes over 4-byte shards = 3 shards, each followed by a 32-byte hash.
-        assert_eq!(bitrot_create_file_size(10, 4, &HashAlgorithm::HighwayHash256), 10 + 3 * 32);
-        assert_eq!(bitrot_create_file_size(10, 4, &HashAlgorithm::None), 10);
-    }
-
-    #[test]
-    fn bitrot_create_file_size_keeps_empty_and_unknown_distinct() {
-        assert_eq!(bitrot_create_file_size(0, 4, &HashAlgorithm::HighwayHash256), 0);
-        // SSE/compression streams advertise SIZE_PRESERVE_LAYER (-1); the remote
-        // put_file_stream receiver relies on a non-positive size to parse the auth
-        // trailer from the stream tail, so the sentinel must survive untouched.
-        assert_eq!(
-            bitrot_create_file_size(rustfs_rio::HashReader::SIZE_PRESERVE_LAYER, 4, &HashAlgorithm::HighwayHash256),
-            rustfs_rio::HashReader::SIZE_PRESERVE_LAYER
-        );
-    }
-
    struct TestChunkReader {
        chunks: VecDeque<Bytes>,
    }
@@ -1412,8 +1412,11 @@ pub(in crate::set_disk) async fn submit_read_repair_heal_with_submitter(

    // Reservation won: this sighting owns the repair records for the object,
    // including the durable journal intent when the caller asked for one.
-    if let Some((kind, version_uuid)) = mrf_intent {
-        rustfs_common::mrf_channel::try_send_mrf_intent(kind, bucket, object, version_uuid);
+    if let Some((kind, version_uuid)) = mrf_intent
+        && let (Ok(pool_index), Ok(set_index)) = (u32::try_from(pool_index), u32::try_from(set_index))
+    {
+        let scope = rustfs_common::mrf_channel::MrfScope { pool_index, set_index };
+        let _ = rustfs_common::mrf_channel::try_send_mrf_intent_typed(kind, bucket, object, version_uuid, Some(scope));
    }

    let mut request = rustfs_common::heal_channel::create_heal_request_with_options(
@@ -2124,13 +2124,26 @@ impl SetDisks {

            let put_object_size = known_put_object_storage_size(data.size());
            let shard_file_size_raw = erasure.shard_file_size(put_object_size);
-            let is_inline_buffer = storage_class_config.should_inline(shard_file_size_raw, erasure.data_shards, opts.versioned);
+            let is_inline_buffer =
+                storage_class_config.should_inline(shard_file_size_raw, erasure.data_shards, opts.versioned);

            let collect_stage_timing = rustfs_io_metrics::put_stage_metrics_enabled() || issue3031_diag_enabled();
            let shard_file_size = shard_file_size_raw;
            let shard_size = erasure.shard_size();
            let write_path = classify_put_write_path(is_inline_buffer, put_object_size, fi.erasure.block_size);
            let direct_inline_commit = matches!(write_path, SmallWritePath::Inline);
+            {
+                use std::io::Write;
+                let msg = format!(
+                    "INLINE_DEBUG: bucket={} obj={} size={} shard_fs={} ds={} bs={} inline={} direct={} path={} iblock={} ver={}\n",
+                    bucket, object, put_object_size, shard_file_size_raw, erasure.data_shards, fi.erasure.block_size,
+                    is_inline_buffer, direct_inline_commit, write_path.metric_label(), storage_class_config.inline_block(), opts.versioned
+                );
+                if let Ok(mut f) = std::fs::OpenOptions::new().create(true).append(true).open("/tmp/rustfs_inline_debug.log") {
+                    let _ = f.write_all(msg.as_bytes());
+                }
+                let _ = std::io::stderr().write_all(msg.as_bytes());
+            }
            rustfs_io_metrics::record_put_object_path(write_path.metric_label());
            let writer_setup_stage_start = collect_stage_timing.then(Instant::now);
            let (mut writers, errors) = if direct_inline_commit {
@@ -6637,12 +6650,23 @@ impl crate::storage_api_contracts::object::ObjectOperations for SetDisks {
    async fn add_partial(&self, bucket: &str, object: &str, version_id: &str) -> Result<()> {
        // MRF journal intent: partial-write recovery must survive a restart
        // (HS-01); the heal request below remains the in-memory fast path.
-        rustfs_common::mrf_channel::try_send_mrf_intent(
-            rustfs_common::mrf_channel::MrfKind::PartialWrite,
-            bucket,
-            object,
-            uuid::Uuid::try_parse(version_id).ok(),
-        );
+        let version_uuid = if version_id.is_empty() {
+            Some(None)
+        } else {
+            uuid::Uuid::try_parse(version_id).ok().map(Some)
+        };
+        if let Some(version_uuid) = version_uuid
+            && let (Ok(pool_index), Ok(set_index)) = (u32::try_from(self.pool_index), u32::try_from(self.set_index))
+        {
+            let scope = rustfs_common::mrf_channel::MrfScope { pool_index, set_index };
+            let _ = rustfs_common::mrf_channel::try_send_mrf_intent_typed(
+                rustfs_common::mrf_channel::MrfKind::PartialWrite,
+                bucket,
+                object,
+                version_uuid,
+                Some(scope),
+            );
+        }
        let mut request = rustfs_common::heal_channel::create_heal_request_with_options(
            bucket.to_string(),
            Some(object.to_string()),
@@ -27,12 +27,12 @@ pub(crate) mod internode {
        NS_SCANNER_BODY_SHA256_QUERY, NS_SCANNER_CAPABILITY_CHALLENGE_QUERY, NS_SCANNER_CYCLE_QUERY,
        NS_SCANNER_LEADER_EPOCH_QUERY, NS_SCANNER_PROTOCOL_VERSION, NS_SCANNER_PROTOCOL_VERSION_QUERY,
        NS_SCANNER_REQUEST_ID_QUERY, NS_SCANNER_SERVER_EPOCH_QUERY, NS_SCANNER_SESSION_ID_QUERY,
-        NS_SCANNER_SESSION_SEQUENCE_QUERY, NS_SCANNER_TIER_REGISTRY_GENERATION_QUERY, NsScannerCapabilityResponse,
-        PUT_FILE_AUTH_QUERY, PUT_FILE_AUTH_TRAILER_DIGEST_LEN, PUT_FILE_AUTH_TRAILER_LEN, PUT_FILE_AUTH_TRAILER_MAC_LEN,
-        PUT_FILE_AUTH_TRAILER_MAGIC, PUT_FILE_AUTH_V1, PUT_FILE_CAPABILITY_CHALLENGE_QUERY, PUT_FILE_CAPABILITY_QUERY,
-        PUT_FILE_CAPABILITY_VERSION, PUT_FILE_NONCE_QUERY, PUT_FILE_SERVER_EPOCH_QUERY, PutFileCapabilityResponse,
-        SCANNER_ACTIVITY_LEGACY_PROTOCOL_VERSION, SCANNER_ACTIVITY_PREVIOUS_PROTOCOL_VERSION, SCANNER_ACTIVITY_PROTOCOL_VERSION,
-        WALK_DIR_BODY_SHA256_QUERY, WALK_DIR_STREAM_COMPLETION_QUERY, WALK_DIR_STREAM_COMPLETION_V1,
+        NS_SCANNER_SESSION_SEQUENCE_QUERY, NsScannerCapabilityResponse, PUT_FILE_AUTH_QUERY, PUT_FILE_AUTH_TRAILER_DIGEST_LEN,
+        PUT_FILE_AUTH_TRAILER_LEN, PUT_FILE_AUTH_TRAILER_MAC_LEN, PUT_FILE_AUTH_TRAILER_MAGIC, PUT_FILE_AUTH_V1,
+        PUT_FILE_CAPABILITY_CHALLENGE_QUERY, PUT_FILE_CAPABILITY_QUERY, PUT_FILE_CAPABILITY_VERSION, PUT_FILE_NONCE_QUERY,
+        PUT_FILE_SERVER_EPOCH_QUERY, PutFileCapabilityResponse, SCANNER_ACTIVITY_LEGACY_PROTOCOL_VERSION,
+        SCANNER_ACTIVITY_PREVIOUS_PROTOCOL_VERSION, SCANNER_ACTIVITY_PROTOCOL_VERSION, WALK_DIR_BODY_SHA256_QUERY,
+        WALK_DIR_STREAM_COMPLETION_QUERY, WALK_DIR_STREAM_COMPLETION_V1,
    };
 }

@@ -3194,7 +3194,7 @@ impl ECStore {

        // Default return value
        let mut del_objects = vec![DeletedObject::default(); objects.len()];
-        let accounting = vec![None; objects.len()];
+        let mut accounting = vec![None; objects.len()];

        let mut del_errs = Vec::with_capacity(objects.len());
        for _ in 0..objects.len() {
@@ -271,7 +271,7 @@ pub(super) fn resolve_latest_object_info_candidates(
            .filter(|candidate| latest_candidate_mod_time(candidate) == Some(latest_mod_time))
            .collect::<Vec<_>>();

-        latest_candidates.sort_by_key(|candidate| std::cmp::Reverse(candidate.idx));
+        latest_candidates.sort_by(|left, right| right.idx.cmp(&left.idx));

        let Some(winner) = latest_candidates.first() else {
            return Err(Error::ErasureReadQuorum);
@@ -119,6 +119,9 @@ struct MrfRepairNoticeTarget {
    bucket: Arc<str>,
    object: Arc<str>,
    version_id: Option<[u8; 16]>,
+    kind: rustfs_common::mrf_channel::MrfKind,
+    scope: Option<rustfs_common::mrf_channel::MrfScope>,
+    lease: Option<rustfs_common::mrf_channel::MrfIngressLease>,
 }

 #[derive(Debug, Clone)]
@@ -889,7 +892,19 @@ impl HealManager {
    }

    fn remove_mrf_repair_notice_targets_for_task(&self, task_id: &str) {
-        lock_mrf_repair_notice_targets(&self.mrf_repair_notice_targets).remove(task_id);
+        let targets = lock_mrf_repair_notice_targets(&self.mrf_repair_notice_targets).remove(task_id);
+        if let Some(targets) = targets {
+            for target in targets {
+                rustfs_common::mrf_channel::release_mrf_identity(
+                    target.kind,
+                    &target.bucket,
+                    &target.object,
+                    target.version_id,
+                    target.scope,
+                    target.lease,
+                );
+            }
+        }
    }

    fn insert_mrf_repair_notice_target(
@@ -1279,7 +1294,20 @@ impl HealManager {
        }
        self.task_aliases.lock().await.clear();
        self.retrying_heals.lock().await.clear();
-        lock_mrf_repair_notice_targets(&self.mrf_repair_notice_targets).clear();
+        let mrf_targets = {
+            let mut registry = lock_mrf_repair_notice_targets(&self.mrf_repair_notice_targets);
+            registry.drain().flat_map(|(_, targets)| targets).collect::<Vec<_>>()
+        };
+        for target in mrf_targets {
+            rustfs_common::mrf_channel::release_mrf_identity(
+                target.kind,
+                &target.bucket,
+                &target.object,
+                target.version_id,
+                target.scope,
+                target.lease,
+            );
+        }
        crate::set_heal_queue_length(0);

        // update state
@@ -1311,12 +1339,32 @@ impl HealManager {
            .await
    }

+    #[cfg(test)]
    pub(crate) async fn submit_mrf_heal_request_with_receipt(
        &self,
        request: HealRequest,
        bucket: Arc<str>,
        object: Arc<str>,
        version_id: Option<[u8; 16]>,
+    ) -> Result<HealAdmissionReceipt> {
+        let kind = match &request.heal_type {
+            HealType::Metadata { .. } => rustfs_common::mrf_channel::MrfKind::MetadataCorruption,
+            HealType::ECDecode { .. } => rustfs_common::mrf_channel::MrfKind::DecodeFailure,
+            _ => rustfs_common::mrf_channel::MrfKind::PartialWrite,
+        };
+        self.submit_mrf_heal_request_with_receipt_and_identity(request, bucket, object, version_id, kind, None, None)
+            .await
+    }
+
+    pub(crate) async fn submit_mrf_heal_request_with_receipt_and_identity(
+        &self,
+        request: HealRequest,
+        bucket: Arc<str>,
+        object: Arc<str>,
+        version_id: Option<[u8; 16]>,
+        kind: rustfs_common::mrf_channel::MrfKind,
+        scope: Option<rustfs_common::mrf_channel::MrfScope>,
+        lease: Option<rustfs_common::mrf_channel::MrfIngressLease>,
    ) -> Result<HealAdmissionReceipt> {
        self.submit_heal_request_with_receipt_alias_and_mrf_notice(
            request,
@@ -1325,6 +1373,9 @@ impl HealManager {
                bucket,
                object,
                version_id,
+                kind,
+                scope,
+                lease,
            }),
        )
        .await
@@ -1539,7 +1590,7 @@ impl HealManager {
            Self::insert_mrf_repair_notice_target(&mut targets, &task_id, target);
        }
        if let Some(displaced_task_id) = &displaced_task_id {
-            lock_mrf_repair_notice_targets(&self.mrf_repair_notice_targets).remove(displaced_task_id);
+            self.remove_mrf_repair_notice_targets_for_task(displaced_task_id);
        }
        drop(retrying_heals);
        drop(queue);
@@ -506,7 +506,18 @@ impl HealManager {
                                    &displaced_terminal,
                                )
                                .await;
-                                lock_mrf_repair_notice_targets(&mrf_repair_notice_targets).remove(&displaced_task_id);
+                                if let Some(targets) = lock_mrf_repair_notice_targets(&mrf_repair_notice_targets).remove(&displaced_task_id) {
+                                    for target in targets {
+                                        rustfs_common::mrf_channel::release_mrf_identity(
+                                            target.kind,
+                                            &target.bucket,
+                                            &target.object,
+                                            target.version_id,
+                                            target.scope,
+                                            target.lease,
+                                        );
+                                    }
+                                }
                            }
                            if matches!(admission, HealAdmissionResult::Accepted) {
                                if should_notify {
@@ -299,7 +299,11 @@ impl PriorityHealQueue {

    /// Create a deduplication key from a heal request
    pub(super) fn make_dedup_key(request: &HealRequest) -> String {
-        Self::make_dedup_key_for_type(&request.heal_type)
+        let base = Self::make_dedup_key_for_type(&request.heal_type);
+        match (&request.heal_type, request.options.set_key()) {
+            (HealType::Object { .. } | HealType::ECDecode { .. }, Some(scope)) => format!("{base}:scope:{scope}"),
+            _ => base,
+        }
    }

    pub(super) fn make_dedup_key_for_type(heal_type: &HealType) -> String {
@@ -349,6 +349,8 @@ impl HealManager {
                            let notice_targets = take_mrf_repair_notice_targets(&mrf_repair_notice_targets_clone, &task_id);
                            if successful_completion {
                                emit_mrf_repaired_events(notice_targets);
+                            } else {
+                                release_mrf_repair_notice_targets(notice_targets);
                            }
                            task_aliases_clone
                                .lock()
@@ -638,7 +640,19 @@ pub(super) fn running_heal_set_counts(active_heals: &HashMap<String, Arc<HealTas
 }

 fn remove_mrf_repair_notice_targets(registry: &Arc<StdMutex<HashMap<String, Vec<MrfRepairNoticeTarget>>>>, task_id: &str) {
-    lock_mrf_repair_notice_targets(registry).remove(task_id);
+    let targets = lock_mrf_repair_notice_targets(registry).remove(task_id);
+    if let Some(targets) = targets {
+        for target in targets {
+            rustfs_common::mrf_channel::release_mrf_identity(
+                target.kind,
+                &target.bucket,
+                &target.object,
+                target.version_id,
+                target.scope,
+                target.lease,
+            );
+        }
+    }
 }

 fn take_mrf_repair_notice_targets(
@@ -671,6 +685,27 @@ fn move_mrf_repair_notice_targets(
 fn emit_mrf_repaired_events(targets: Vec<MrfRepairNoticeTarget>) {
    for target in targets {
        rustfs_common::mrf_channel::note_mrf_repaired(&target.bucket, &target.object, target.version_id);
+        rustfs_common::mrf_channel::release_mrf_identity(
+            target.kind,
+            &target.bucket,
+            &target.object,
+            target.version_id,
+            target.scope,
+            target.lease,
+        );
+    }
+}
+
+fn release_mrf_repair_notice_targets(targets: Vec<MrfRepairNoticeTarget>) {
+    for target in targets {
+        rustfs_common::mrf_channel::release_mrf_identity(
+            target.kind,
+            &target.bucket,
+            &target.object,
+            target.version_id,
+            target.scope,
+            target.lease,
+        );
    }
 }

@@ -37,7 +37,7 @@ use crate::heal::manager::HealManager;
 use metrics::{counter, gauge};
 use rustfs_common::heal_channel::{HealAdmissionDropReason, HealAdmissionResult};
 use rustfs_common::mrf_channel::{MRF_MAX_ATTEMPTS, MrfIntent};
-use std::collections::VecDeque;
+use std::collections::{HashSet, VecDeque};
 use std::sync::Arc;
 use std::time::Duration;
 use tokio::sync::mpsc;
@@ -48,15 +48,27 @@ use crate::heal::task::{HealOptions, HealPriority, HealRequest, HealType};
 /// Journal location inside the metadata bucket, following the resume-state
 /// layout.
 pub(crate) const MRF_JOURNAL_PATH: &str = "buckets/.heal/mrf/journal.bin";
+/// The scoped path is the authoritative snapshot for new readers and carries
+/// both v1 and v2 records. The legacy path is only a v1 compatibility mirror;
+/// older readers ignore the authoritative path, while new readers never merge
+/// the two files. This prevents a partial two-file flush from fabricating a
+/// mixed epoch.
+pub(crate) const MRF_SCOPED_JOURNAL_PATH: &str = "buckets/.heal/mrf/journal-scoped.bin";

 /// Record format tag.
 const MRF_JOURNAL_FORMAT: u8 = 1;
 /// Record layout version.
 const MRF_JOURNAL_VERSION: u8 = 1;
+const MRF_JOURNAL_VERSION_SCOPED: u8 = 2;

 /// Fixed header size: format, version, kind, attempts, enqueued_at_ms,
 /// has_version flag.
 const MRF_RECORD_FIXED_HEAD: usize = 1 + 1 + 1 + 1 + 8 + 1;
+const MRF_MAX_IDENTITY_COMPONENT: usize = 1024;
+
+fn metric_f64(value: usize) -> f64 {
+    f64::from(u32::try_from(value).unwrap_or(u32::MAX))
+}

 #[derive(Debug, Clone)]
 pub(crate) struct MrfConsumerConfig {
@@ -101,40 +113,90 @@ impl Default for MrfConsumerConfig {
 /// incoming intent (never a resident one) and counts the loss.
 pub(crate) struct MrfQueue {
    pending: VecDeque<MrfIntent>,
+    pending_keys: HashSet<MrfQueueKey>,
    bytes: usize,
    capacity: usize,
    byte_budget: usize,
 }

+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+struct MrfQueueKey {
+    kind: rustfs_common::mrf_channel::MrfKind,
+    bucket: Arc<str>,
+    object: Arc<str>,
+    version_id: Option<[u8; 16]>,
+    scope: Option<rustfs_common::mrf_channel::MrfScope>,
+}
+
+fn queue_key(intent: &MrfIntent) -> MrfQueueKey {
+    let version_id = intent.version_id.filter(|bytes| *bytes != [0; 16]);
+    let scope = (!matches!(intent.kind, rustfs_common::mrf_channel::MrfKind::MetadataCorruption))
+        .then_some(intent.scope)
+        .flatten();
+    MrfQueueKey {
+        kind: intent.kind,
+        bucket: intent.bucket.clone(),
+        object: intent.object.clone(),
+        version_id,
+        scope,
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(crate) enum MrfQueuePushResult {
+    Enqueued,
+    Coalesced,
+    Rejected,
+}
+
 impl MrfQueue {
    pub(crate) fn new(capacity: usize, byte_budget: usize) -> Self {
        Self {
            pending: VecDeque::new(),
+            pending_keys: HashSet::new(),
            bytes: 0,
            capacity,
            byte_budget,
        }
    }

-    /// Returns `false` (after counting) when either ceiling would be crossed.
-    pub(crate) fn try_push(&mut self, intent: MrfIntent) -> bool {
+    pub(crate) fn try_push_typed(&mut self, intent: MrfIntent) -> MrfQueuePushResult {
+        if intent.bucket.len() > MRF_MAX_IDENTITY_COMPONENT || intent.object.len() > MRF_MAX_IDENTITY_COMPONENT {
+            counter!("rustfs_heal_mrf_dropped_total", "reason" => "identity_oversized").increment(1);
+            return MrfQueuePushResult::Rejected;
+        }
+        let key = queue_key(&intent);
+        if self.pending_keys.contains(&key) {
+            counter!("rustfs_heal_mrf_coalesced_total", "layer" => "queue").increment(1);
+            return MrfQueuePushResult::Coalesced;
+        }
        let cost = intent.estimated_bytes();
        if self.pending.len() >= self.capacity || self.bytes + cost > self.byte_budget {
            counter!("rustfs_heal_mrf_dropped_total", "reason" => "queue_overflow").increment(1);
-            return false;
+            return MrfQueuePushResult::Rejected;
        }
        self.bytes += cost;
+        self.pending_keys.insert(key);
        self.pending.push_back(intent);
-        true
+        MrfQueuePushResult::Enqueued
+    }
+
+    /// Bool compatibility adapter: only a newly executable queue item is
+    /// reported as accepted; a coalesced duplicate is not durable admission.
+    #[cfg(test)]
+    pub(crate) fn try_push(&mut self, intent: MrfIntent) -> bool {
+        matches!(self.try_push_typed(intent), MrfQueuePushResult::Enqueued)
    }

    pub(crate) fn pop_front(&mut self) -> Option<MrfIntent> {
        let intent = self.pending.pop_front()?;
+        self.pending_keys.remove(&queue_key(&intent));
        self.bytes = self.bytes.saturating_sub(intent.estimated_bytes());
        Some(intent)
    }

    pub(crate) fn push_back(&mut self, intent: MrfIntent) {
+        self.pending_keys.insert(queue_key(&intent));
        self.bytes += intent.estimated_bytes();
        self.pending.push_back(intent);
    }
@@ -157,10 +219,24 @@ impl MrfQueue {
 // ---------------------------------------------------------------------------

 /// Append one encoded record to `out`.
-pub(crate) fn encode_intent(intent: &MrfIntent, out: &mut Vec<u8>) {
+pub(crate) fn encode_intent(intent: &MrfIntent, out: &mut Vec<u8>) -> bool {
+    let Ok(bucket_len) = u32::try_from(intent.bucket.len()) else {
+        return false;
+    };
+    let Ok(object_len) = u32::try_from(intent.object.len()) else {
+        return false;
+    };
+    let scope = (!matches!(intent.kind, rustfs_common::mrf_channel::MrfKind::MetadataCorruption))
+        .then_some(intent.scope)
+        .flatten();
+    let version_id = intent.version_id.filter(|bytes| *bytes != [0; 16]);
    let start = out.len();
    out.push(MRF_JOURNAL_FORMAT);
-    out.push(MRF_JOURNAL_VERSION);
+    out.push(if scope.is_some() {
+        MRF_JOURNAL_VERSION_SCOPED
+    } else {
+        MRF_JOURNAL_VERSION
+    });
    out.push(match intent.kind {
        rustfs_common::mrf_channel::MrfKind::DecodeFailure => 1,
        rustfs_common::mrf_channel::MrfKind::MetadataCorruption => 2,
@@ -168,27 +244,36 @@ pub(crate) fn encode_intent(intent: &MrfIntent, out: &mut Vec<u8>) {
    });
    out.push(intent.attempts);
    out.extend_from_slice(&intent.enqueued_at_ms.to_le_bytes());
-    match intent.version_id {
+    match version_id {
        Some(bytes) => {
            out.push(1);
            out.extend_from_slice(&bytes);
        }
        None => out.push(0),
    }
-    out.extend_from_slice(&(intent.bucket.len() as u32).to_le_bytes());
-    out.extend_from_slice(&(intent.object.len() as u32).to_le_bytes());
+    if let Some(scope) = scope {
+        out.extend_from_slice(&scope.pool_index.to_le_bytes());
+        out.extend_from_slice(&scope.set_index.to_le_bytes());
+    }
+    out.extend_from_slice(&bucket_len.to_le_bytes());
+    out.extend_from_slice(&object_len.to_le_bytes());
    out.extend_from_slice(intent.bucket.as_bytes());
    out.extend_from_slice(intent.object.as_bytes());
    let mut hasher = crc_fast::Digest::new(crc_fast::CrcAlgorithm::Crc32IsoHdlc);
    hasher.update(&out[start..]);
-    out.extend_from_slice(&(hasher.finalize() as u32).to_le_bytes());
+    let Ok(checksum) = u32::try_from(hasher.finalize()) else {
+        out.truncate(start);
+        return false;
+    };
+    out.extend_from_slice(&checksum.to_le_bytes());
+    true
 }

 fn decode_one(data: &[u8]) -> Option<(MrfIntent, usize)> {
    if data.len() < MRF_RECORD_FIXED_HEAD + 8 {
        return None;
    }
-    if data[0] != MRF_JOURNAL_FORMAT || data[1] != MRF_JOURNAL_VERSION {
+    if data[0] != MRF_JOURNAL_FORMAT || !matches!(data[1], MRF_JOURNAL_VERSION | MRF_JOURNAL_VERSION_SCOPED) {
        return None;
    }
    let kind = match data[2] {
@@ -198,24 +283,38 @@ fn decode_one(data: &[u8]) -> Option<(MrfIntent, usize)> {
        _ => return None,
    };
    let attempts = data[3];
-    let enqueued_at_ms = u64::from_le_bytes(data[4..12].try_into().expect("slice length checked"));
+    let enqueued_at_ms = u64::from_le_bytes(data[4..12].try_into().ok()?);
    let has_version = data[12] != 0;
    let mut cursor = MRF_RECORD_FIXED_HEAD;
    let version_id = if has_version {
        if data.len() < cursor + 16 {
            return None;
        }
-        let bytes: [u8; 16] = data[cursor..cursor + 16].try_into().expect("slice length checked");
+        let bytes: [u8; 16] = data[cursor..cursor + 16].try_into().ok()?;
        cursor += 16;
        Some(bytes)
    } else {
        None
    };
+    let scope = if data[1] == MRF_JOURNAL_VERSION_SCOPED {
+        if data.len() < cursor + 8 {
+            return None;
+        }
+        let pool_index = u32::from_le_bytes(data[cursor..cursor + 4].try_into().ok()?);
+        let set_index = u32::from_le_bytes(data[cursor + 4..cursor + 8].try_into().ok()?);
+        cursor += 8;
+        Some(rustfs_common::mrf_channel::MrfScope { pool_index, set_index })
+    } else {
+        None
+    };
    if data.len() < cursor + 8 {
        return None;
    }
-    let bucket_len = u32::from_le_bytes(data[cursor..cursor + 4].try_into().expect("slice length checked")) as usize;
-    let object_len = u32::from_le_bytes(data[cursor + 4..cursor + 8].try_into().expect("slice length checked")) as usize;
+    let bucket_len = usize::try_from(u32::from_le_bytes(data[cursor..cursor + 4].try_into().ok()?)).ok()?;
+    let object_len = usize::try_from(u32::from_le_bytes(data[cursor + 4..cursor + 8].try_into().ok()?)).ok()?;
+    if bucket_len > MRF_MAX_IDENTITY_COMPONENT || object_len > MRF_MAX_IDENTITY_COMPONENT {
+        return None;
+    }
    cursor += 8;
    let body_end = cursor.checked_add(bucket_len)?.checked_add(object_len)?;
    let record_end = body_end.checked_add(4)?;
@@ -224,7 +323,7 @@ fn decode_one(data: &[u8]) -> Option<(MrfIntent, usize)> {
    }
    let mut hasher = crc_fast::Digest::new(crc_fast::CrcAlgorithm::Crc32IsoHdlc);
    hasher.update(&data[..body_end]);
-    if (hasher.finalize() as u32) != u32::from_le_bytes(data[body_end..record_end].try_into().expect("slice length checked")) {
+    if u32::try_from(hasher.finalize()).ok()? != u32::from_le_bytes(data[body_end..record_end].try_into().ok()?) {
        return None;
    }
    let bucket = std::sync::Arc::from(std::str::from_utf8(&data[cursor..cursor + bucket_len]).ok()?);
@@ -235,6 +334,12 @@ fn decode_one(data: &[u8]) -> Option<(MrfIntent, usize)> {
            object,
            version_id,
            kind,
+            scope: if matches!(kind, rustfs_common::mrf_channel::MrfKind::MetadataCorruption) {
+                None
+            } else {
+                scope
+            },
+            lease: None,
            enqueued_at_ms,
            attempts,
        },
@@ -269,9 +374,9 @@ async fn journal_disks() -> Vec<DiskStore> {
    map.values().flatten().cloned().collect()
 }

-async fn read_journal() -> Option<Vec<u8>> {
+async fn read_journal(path: &str) -> Option<Vec<u8>> {
    for disk in journal_disks().await {
-        match disk.read_all(super::RUSTFS_META_BUCKET, MRF_JOURNAL_PATH).await {
+        match disk.read_all(super::RUSTFS_META_BUCKET, path).await {
            Ok(bytes) => return Some(bytes.to_vec()),
            Err(_) => continue,
        }
@@ -282,35 +387,51 @@ async fn read_journal() -> Option<Vec<u8>> {
 /// Write the snapshot to every local disk; returns true when at least one
 /// disk accepted it, so a total write failure keeps the runtime dirty and
 /// the next tick retries the persist.
-async fn write_journal(data: &[u8]) -> bool {
+async fn write_journal(path: &str, data: &[u8]) -> bool {
    let payload = bytes::Bytes::copy_from_slice(data);
    let mut any_persisted = false;
    for disk in journal_disks().await {
-        match disk
-            .write_all(super::RUSTFS_META_BUCKET, MRF_JOURNAL_PATH, payload.clone())
-            .await
-        {
+        match disk.write_all(super::RUSTFS_META_BUCKET, path, payload.clone()).await {
            Ok(()) => any_persisted = true,
            Err(err) => warn_mrf_journal_write(&err),
        }
    }
-    if !data.is_empty() {
-        counter!("rustfs_heal_mrf_journal_fsync_total").increment(1);
-    }
-    gauge!("rustfs_heal_mrf_journal_bytes").set(data.len() as f64);
    any_persisted
 }

-async fn delete_journal() {
-    for disk in journal_disks().await {
-        let _ = disk
+async fn delete_journal(path: &str) -> bool {
+    let disks = journal_disks().await;
+    if disks.is_empty() {
+        counter!("rustfs_heal_mrf_journal_delete_failures_total").increment(1);
+        return false;
+    }
+    let mut all_deleted = true;
+    for disk in disks {
+        let result = disk
            .delete(
                super::RUSTFS_META_BUCKET,
-                MRF_JOURNAL_PATH,
+                path,
                crate::heal::storage_api::owner::EcstoreDeleteOptions::default(),
            )
            .await;
+        if let Err(err) = result {
+            // Delete is idempotent: a compatibility mirror that was never
+            // written (or was already removed) is clean, not a retry state.
+            if !matches!(err, super::DiskError::FileNotFound | super::DiskError::VolumeNotFound) {
+                all_deleted = false;
+            }
+        }
    }
+    if !all_deleted {
+        counter!("rustfs_heal_mrf_journal_delete_failures_total").increment(1);
+    }
+    all_deleted
+}
+
+async fn delete_journals() -> bool {
+    let authoritative_deleted = delete_journal(MRF_SCOPED_JOURNAL_PATH).await;
+    let legacy_deleted = delete_journal(MRF_JOURNAL_PATH).await;
+    authoritative_deleted && legacy_deleted
 }

 fn warn_mrf_journal_write(err: &super::DiskError) {
@@ -331,7 +452,10 @@ fn warn_mrf_journal_write(err: &super::DiskError) {
 pub(crate) fn build_heal_request(intent: &MrfIntent) -> HealRequest {
    let bucket = intent.bucket.to_string();
    let object = intent.object.to_string();
-    let version_id = intent.version_id.map(|bytes| Uuid::from_bytes(bytes).to_string());
+    let version_id = intent
+        .version_id
+        .filter(|bytes| *bytes != [0; 16])
+        .map(|bytes| Uuid::from_bytes(bytes).to_string());
    let (heal_type, priority) = match intent.kind {
        rustfs_common::mrf_channel::MrfKind::DecodeFailure => (
            HealType::ECDecode {
@@ -351,18 +475,28 @@ pub(crate) fn build_heal_request(intent: &MrfIntent) -> HealRequest {
            HealPriority::Normal,
        ),
    };
-    let mut request = HealRequest::new(heal_type, HealOptions::default(), priority);
+    let mut options = HealOptions::default();
+    if !matches!(intent.kind, rustfs_common::mrf_channel::MrfKind::MetadataCorruption)
+        && let Some(scope) = intent.scope
+    {
+        options.pool_index = usize::try_from(scope.pool_index).ok();
+        options.set_index = usize::try_from(scope.set_index).ok();
+    }
+    let mut request = HealRequest::new(heal_type, options, priority);
    request.source = rustfs_common::heal_channel::HealRequestSource::Mrf;
    request
 }

 async fn submit_mrf_heal_request(manager: &HealManager, intent: &MrfIntent) -> crate::Result<HealAdmissionResult> {
    let receipt = manager
-        .submit_mrf_heal_request_with_receipt(
+        .submit_mrf_heal_request_with_receipt_and_identity(
            build_heal_request(intent),
            intent.bucket.clone(),
            intent.object.clone(),
            intent.version_id,
+            intent.kind,
+            intent.scope,
+            intent.lease,
        )
        .await?;
    Ok(receipt.result)
@@ -387,16 +521,38 @@ struct MrfRuntime {
 }

 impl MrfRuntime {
-    fn snapshot(&self) -> Vec<u8> {
-        let mut buf = Vec::new();
+    fn snapshot(&self) -> (Vec<u8>, Vec<u8>) {
+        let mut authoritative = Vec::new();
+        let mut legacy = Vec::new();
        for intent in self.queue.intents() {
-            encode_intent(intent, &mut buf);
+            let scoped_identity =
+                !matches!(intent.kind, rustfs_common::mrf_channel::MrfKind::MetadataCorruption) && intent.scope.is_some();
+            if !encode_intent(intent, &mut authoritative) {
+                counter!("rustfs_heal_mrf_dropped_total", "reason" => "journal_identity_oversized").increment(1);
+            }
+            if !scoped_identity && !encode_intent(intent, &mut legacy) {
+                counter!("rustfs_heal_mrf_dropped_total", "reason" => "journal_identity_oversized").increment(1);
+            }
        }
-        buf
+        (authoritative, legacy)
    }

    async fn flush(&mut self) {
-        let persisted = write_journal(&self.snapshot()).await;
+        let (authoritative, legacy) = self.snapshot();
+        let authoritative_persisted = write_journal(MRF_SCOPED_JOURNAL_PATH, &authoritative).await;
+        if !authoritative.is_empty() {
+            counter!("rustfs_heal_mrf_journal_fsync_total").increment(1);
+        }
+        gauge!("rustfs_heal_mrf_journal_bytes").set(metric_f64(authoritative.len()));
+        // Publish the compatibility mirror only after the authoritative
+        // snapshot has reached at least one disk. This ordering prevents an
+        // old reader from observing a newer epoch that a new reader cannot
+        // see when the canonical write is unavailable.
+        let legacy_persisted = authoritative_persisted && write_journal(MRF_JOURNAL_PATH, &legacy).await;
+        // Keep dirty until both the authoritative snapshot and its
+        // compatibility mirror have been accepted; otherwise a one-sided
+        // failure would never retry the missing file.
+        let persisted = authoritative_persisted && legacy_persisted;
        self.new_since_flush = 0;
        // Keep the dirty flag when every disk write failed: a clean backlog
        // would otherwise never rewrite, losing the periodic persist retry a
@@ -404,7 +560,7 @@ impl MrfRuntime {
        if persisted {
            self.dirty = false;
        }
-        self.journal_on_disk = true;
+        self.journal_on_disk |= authoritative_persisted || legacy_persisted;
    }

    /// Drain pending intents into the heal manager until it is full, the
@@ -430,6 +586,7 @@ impl MrfRuntime {
                    intent.attempts = intent.attempts.saturating_add(1);
                    if intent.attempts >= MRF_MAX_ATTEMPTS {
                        counter!("rustfs_heal_mrf_dropped_total", "reason" => "attempts_exhausted").increment(1);
+                        rustfs_common::mrf_channel::release_mrf_intent(&intent);
                        continue;
                    }
                    self.queue.push_back(intent);
@@ -438,11 +595,13 @@ impl MrfRuntime {
                }
                Ok(HealAdmissionResult::Dropped(_)) => {
                    counter!("rustfs_heal_mrf_dropped_total", "reason" => "admission_policy").increment(1);
+                    rustfs_common::mrf_channel::release_mrf_intent(&intent);
                }
                Err(_) => {
                    intent.attempts = intent.attempts.saturating_add(1);
                    if intent.attempts >= MRF_MAX_ATTEMPTS {
                        counter!("rustfs_heal_mrf_dropped_total", "reason" => "attempts_exhausted").increment(1);
+                        rustfs_common::mrf_channel::release_mrf_intent(&intent);
                        continue;
                    }
                    self.queue.push_back(intent);
@@ -451,8 +610,8 @@ impl MrfRuntime {
                }
            }
        }
-        gauge!("rustfs_heal_mrf_queue_depth").set(self.queue.depth() as f64);
-        gauge!("rustfs_heal_mrf_queue_bytes").set(self.queue.bytes() as f64);
+        gauge!("rustfs_heal_mrf_queue_depth").set(metric_f64(self.queue.depth()));
+        gauge!("rustfs_heal_mrf_queue_bytes").set(metric_f64(self.queue.bytes()));
    }
 }

@@ -496,7 +655,12 @@ pub async fn replay_journal_once(manager: &Arc<HealManager>) -> usize {
    let config = MrfConsumerConfig::default();
    let mut queue = MrfQueue::new(config.queue_capacity, config.journal_max_bytes);
    let mut backoff_until: Option<tokio::time::Instant> = None;
-    replay_into(manager, &mut queue, &mut backoff_until).await
+    replay_into(manager, &mut queue, &mut backoff_until).await.replayed
+}
+
+struct ReplayOutcome {
+    replayed: usize,
+    journal_on_disk: bool,
 }

 /// Shared replay core: read + decode + re-arm + delete, then drain what fits.
@@ -504,11 +668,25 @@ async fn replay_into(
    manager: &Arc<HealManager>,
    queue: &mut MrfQueue,
    backoff_until: &mut Option<tokio::time::Instant>,
-) -> usize {
-    let Some(data) = read_journal().await else {
-        return 0;
+) -> ReplayOutcome {
+    // The scoped file is a complete authoritative snapshot. Fall back to the
+    // legacy mirror only when the authoritative path is unavailable; merging
+    // both files could combine records from different flush epochs.
+    let data = match read_journal(MRF_SCOPED_JOURNAL_PATH).await {
+        Some(data) => data,
+        None => match read_journal(MRF_JOURNAL_PATH).await {
+            Some(data) => data,
+            None => {
+                return ReplayOutcome {
+                    replayed: 0,
+                    journal_on_disk: false,
+                };
+            }
+        },
    };
-    let (intents, truncated) = decode_journal(&data);
+    let mut intents = Vec::new();
+    let (decoded, truncated) = decode_journal(&data);
+    intents.extend(decoded);
    if truncated > 0 {
        tracing::warn!(
            target: "rustfs::heal::mrf",
@@ -516,12 +694,15 @@ async fn replay_into(
            "MRF journal had a torn tail; truncated records were discarded"
        );
    }
-    counter!("rustfs_heal_mrf_replayed_total").increment(intents.len() as u64);
+    counter!("rustfs_heal_mrf_replayed_total").increment(u64::try_from(intents.len()).unwrap_or(u64::MAX));
    let replayed = intents.len();
    for intent in intents {
-        queue.try_push(intent);
+        let result = queue.try_push_typed(intent.clone());
+        if !matches!(result, MrfQueuePushResult::Enqueued) {
+            rustfs_common::mrf_channel::release_mrf_intent(&intent);
+        }
    }
-    delete_journal().await;
+    let journal_on_disk = !delete_journals().await;

    // Drain the replayed intents immediately; whatever the manager refuses
    // stays armed in `queue` for the consumer's retry loop.
@@ -541,7 +722,10 @@ async fn replay_into(
            }
        }
    }
-    replayed
+    ReplayOutcome {
+        replayed,
+        journal_on_disk,
+    }
 }

 /// Replay the journal, then keep draining the channel into the heal manager
@@ -559,7 +743,8 @@ async fn run_mrf_consumer(manager: Arc<HealManager>, mut receiver: mpsc::Receive

    // Replay: read the journal, re-arm intents (duplicates are merged by the
    // manager's dedup key), then drop the file so the next flush starts clean.
-    replay_into(&manager, &mut runtime.queue, &mut runtime.backoff_until).await;
+    let replay = replay_into(&manager, &mut runtime.queue, &mut runtime.backoff_until).await;
+    runtime.journal_on_disk = replay.journal_on_disk;
    // The replay deleted the journal file; anything still pending (e.g. the
    // manager was full and backoff armed) must be re-persisted by the next
    // flush or a crash before it would lose those intents.
@@ -587,9 +772,14 @@ async fn run_mrf_consumer(manager: Arc<HealManager>, mut receiver: mpsc::Receive
                    return;
                }
                for intent in batch.drain(..) {
-                    if runtime.queue.try_push(intent) {
-                        runtime.new_since_flush += 1;
-                        runtime.dirty = true;
+                    match runtime.queue.try_push_typed(intent.clone()) {
+                        MrfQueuePushResult::Enqueued => {
+                            runtime.new_since_flush += 1;
+                            runtime.dirty = true;
+                        }
+                        MrfQueuePushResult::Coalesced | MrfQueuePushResult::Rejected => {
+                            rustfs_common::mrf_channel::release_mrf_intent(&intent);
+                        }
                    }
                }
                runtime.dispatch(manager.as_ref()).await;
@@ -613,13 +803,14 @@ async fn run_mrf_consumer(manager: Arc<HealManager>, mut receiver: mpsc::Receive
                    TickAction::DeleteJournal => {
                        // All intents consumed: remove the journal so a restart
                        // replays nothing (mirrors MinIO's post-replay unlink).
-                        delete_journal().await;
-                        runtime.journal_on_disk = false;
-                        gauge!("rustfs_heal_mrf_journal_bytes").set(0.0);
+                        if delete_journals().await {
+                            runtime.journal_on_disk = false;
+                            gauge!("rustfs_heal_mrf_journal_bytes").set(0.0);
+                        }
                    }
                    TickAction::Idle => {}
                }
-                gauge!("rustfs_heal_mrf_queue_depth").set(runtime.queue.depth() as f64);
+                gauge!("rustfs_heal_mrf_queue_depth").set(metric_f64(runtime.queue.depth()));
            }
        }
    }
@@ -664,6 +855,8 @@ mod tests {
            object: StdArc::from(object),
            version_id: Some([7u8; 16]),
            kind: MrfKind::DecodeFailure,
+            scope: None,
+            lease: None,
            enqueued_at_ms: 1_700_000_000_000,
            attempts,
        }
@@ -694,17 +887,101 @@ mod tests {
    fn queue_enforces_count_and_byte_ceilings() {
        let mut queue = MrfQueue::new(2, usize::MAX);
        assert!(queue.try_push(intent("b", "o", 0)));
-        assert!(queue.try_push(intent("b", "o", 0)));
-        assert!(!queue.try_push(intent("b", "o", 0)), "count ceiling must drop");
+        assert!(queue.try_push(intent("b", "o2", 0)));
+        assert!(!queue.try_push(intent("b", "o3", 0)), "count ceiling must drop");

        let mut tiny = MrfQueue::new(usize::MAX, intent("bucket", "object", 0).estimated_bytes());
        assert!(tiny.try_push(intent("bucket", "object", 0)));
        assert!(
-            !tiny.try_push(intent("bucket", "object", 0)),
+            !tiny.try_push(intent("bucket", "object2", 0)),
            "byte budget must drop before the second intent fits"
        );
    }

+    #[test]
+    fn duplicate_mrf_intents_coalesce_to_one_execution() {
+        let mut queue = MrfQueue::new(1000, usize::MAX);
+        let mut enqueued = 0;
+        let mut coalesced = 0;
+        assert_eq!(queue.try_push_typed(intent("bucket", "object", 0)), MrfQueuePushResult::Enqueued);
+        enqueued += 1;
+        for _ in 0..999 {
+            match queue.try_push_typed(intent("bucket", "object", 0)) {
+                MrfQueuePushResult::Coalesced => coalesced += 1,
+                other => panic!("duplicate intent was not coalesced: {other:?}"),
+            }
+        }
+        assert_eq!(enqueued, 1);
+        assert_eq!(coalesced, 999);
+        assert_eq!(queue.depth(), 1);
+    }
+
+    #[test]
+    fn mrf_dedupe_does_not_merge_adjacent_version_pool_or_kind() {
+        let mut queue = MrfQueue::new(8, usize::MAX);
+        let mut first = intent("bucket", "object", 0);
+        first.kind = MrfKind::PartialWrite;
+        first.scope = Some(rustfs_common::mrf_channel::MrfScope {
+            pool_index: 1,
+            set_index: 1,
+        });
+        assert!(queue.try_push(first.clone()));
+        first.version_id = Some([8u8; 16]);
+        assert!(queue.try_push(first));
+        let mut other_scope = intent("bucket", "object", 0);
+        other_scope.kind = MrfKind::PartialWrite;
+        other_scope.scope = Some(rustfs_common::mrf_channel::MrfScope {
+            pool_index: 2,
+            set_index: 1,
+        });
+        assert!(queue.try_push(other_scope));
+        let mut other_kind = intent("bucket", "object", 0);
+        other_kind.kind = MrfKind::DecodeFailure;
+        other_kind.scope = None;
+        assert!(queue.try_push(other_kind));
+        assert_eq!(queue.depth(), 4);
+    }
+
+    #[test]
+    fn mrf_dedupe_full_returns_rejected_with_durable_pending() {
+        let mut queue = MrfQueue::new(1, usize::MAX);
+        assert_eq!(queue.try_push_typed(intent("bucket", "object", 0)), MrfQueuePushResult::Enqueued);
+        assert_eq!(queue.try_push_typed(intent("bucket", "other", 0)), MrfQueuePushResult::Rejected);
+        assert_eq!(queue.depth(), 1);
+        let mut snapshot = Vec::new();
+        assert!(encode_intent(queue.intents().next().expect("resident intent"), &mut snapshot));
+        assert!(!snapshot.is_empty(), "the resident intent remains journalable after rejection");
+    }
+
+    #[test]
+    fn mrf_dedupe_failure_releases_key_for_retry() {
+        let mut queue = MrfQueue::new(1, usize::MAX);
+        assert_eq!(queue.try_push_typed(intent("bucket", "object", 0)), MrfQueuePushResult::Enqueued);
+        let _failed = queue.pop_front().expect("queued intent");
+        assert_eq!(queue.try_push_typed(intent("bucket", "object", 1)), MrfQueuePushResult::Enqueued);
+        assert_eq!(queue.depth(), 1);
+    }
+
+    #[test]
+    fn mrf_dedupe_key_and_map_are_bounded() {
+        let mut queue = MrfQueue::new(2, usize::MAX);
+        assert_eq!(queue.try_push_typed(intent("bucket", "object", 0)), MrfQueuePushResult::Enqueued);
+        assert_eq!(queue.try_push_typed(intent("bucket", "other", 0)), MrfQueuePushResult::Enqueued);
+        assert_eq!(queue.pending_keys.len(), 2);
+        assert_eq!(queue.try_push_typed(intent("bucket", "third", 0)), MrfQueuePushResult::Rejected);
+        assert_eq!(queue.depth(), 2);
+    }
+
+    #[test]
+    fn cross_node_duplicate_execution_remains_idempotent() {
+        // Node-local ingress maps intentionally do not merge across nodes;
+        // the manager's existing identity key absorbs the duplicate later.
+        let mut node_a = MrfQueue::new(8, usize::MAX);
+        let mut node_b = MrfQueue::new(8, usize::MAX);
+        assert_eq!(node_a.try_push_typed(intent("bucket", "object", 0)), MrfQueuePushResult::Enqueued);
+        assert_eq!(node_b.try_push_typed(intent("bucket", "object", 0)), MrfQueuePushResult::Enqueued);
+    }
+
    #[test]
    fn journal_roundtrip_preserves_intents() {
        let intents = vec![
@@ -715,6 +992,8 @@ mod tests {
                object: StdArc::from("object/c"),
                version_id: None,
                kind: MrfKind::MetadataCorruption,
+                scope: None,
+                lease: None,
                enqueued_at_ms: 5,
                attempts: 1,
            },
@@ -766,6 +1045,8 @@ mod tests {
            object: StdArc::from("o"),
            version_id: None,
            kind: MrfKind::MetadataCorruption,
+            scope: None,
+            lease: None,
            enqueued_at_ms: 0,
            attempts: 0,
        });
@@ -777,6 +1058,8 @@ mod tests {
            object: StdArc::from("o"),
            version_id: None,
            kind: MrfKind::PartialWrite,
+            scope: None,
+            lease: None,
            enqueued_at_ms: 0,
            attempts: 0,
        });
@@ -35,6 +35,7 @@ use storage_api::endpoint_index::{Endpoint, EndpointServerPools, Endpoints, Pool

 const META_BUCKET: &str = ".rustfs.sys";
 const JOURNAL_REL: &str = "buckets/.heal/mrf/journal.bin";
+const SCOPED_JOURNAL_REL: &str = "buckets/.heal/mrf/journal-scoped.bin";

 async fn heal_env() -> (Vec<std::path::PathBuf>, Arc<dyn HealStorageAPI>) {
    let env = rustfs_test_utils::TestECStoreEnv::builder()
@@ -79,14 +80,18 @@ fn journal_record(kind: u8, bucket: &str, object: &str, version: Option<[u8; 16]
    body
 }

-fn write_journal_to_disks(disk_paths: &[std::path::PathBuf], data: &[u8]) {
+fn write_journal_path_to_disks(disk_paths: &[std::path::PathBuf], relative_path: &str, data: &[u8]) {
    for path in disk_paths {
-        let journal = path.join(META_BUCKET).join(JOURNAL_REL);
+        let journal = path.join(META_BUCKET).join(relative_path);
        std::fs::create_dir_all(journal.parent().expect("journal parent")).expect("create journal dir");
        std::fs::write(&journal, data).expect("write journal fixture");
    }
 }

+fn write_journal_to_disks(disk_paths: &[std::path::PathBuf], data: &[u8]) {
+    write_journal_path_to_disks(disk_paths, JOURNAL_REL, data);
+}
+
 async fn wait_until<F, Fut>(deadline: Duration, mut probe: F) -> bool
 where
    F: FnMut() -> Fut,
@@ -187,8 +192,73 @@ async fn journal_replay_arms_intents_and_deletes_the_file() {
            .all(|path| !Path::new(path).join(META_BUCKET).join(JOURNAL_REL).exists()),
        "the journal file must be removed after a successful replay"
    );
+    assert!(
+        disk_paths
+            .iter()
+            .all(|path| !Path::new(path).join(META_BUCKET).join(SCOPED_JOURNAL_REL).exists()),
+        "the authoritative journal file must also be removed after replay"
+    );

    let snapshot = manager.operations_snapshot().await;
    assert_eq!(snapshot.queued_by_priority.urgent, 1, "the decode-failure record must replay as Urgent");
    assert!(snapshot.queued_by_priority.normal >= 1, "the partial-write record must replay as Normal");
 }
+
+/// A canonical snapshot and its compatibility mirror may differ after a
+/// partial flush. Replay must choose the complete canonical epoch instead of
+/// combining records that never coexisted in memory.
+#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
+#[serial]
+async fn authoritative_journal_is_not_merged_with_legacy_mirror() {
+    let (disk_paths, storage) = heal_env().await;
+    let mut endpoints: Vec<Endpoint> = disk_paths
+        .iter()
+        .map(|p| Endpoint::try_from(p.to_string_lossy().as_ref()).expect("endpoint from disk path"))
+        .collect();
+    for (i, endpoint) in endpoints.iter_mut().enumerate() {
+        endpoint.set_pool_index(0);
+        endpoint.set_set_index(0);
+        endpoint.set_disk_index(i);
+    }
+    let pool = PoolEndpoints {
+        legacy: false,
+        set_count: 1,
+        drives_per_set: endpoints.len(),
+        endpoints: Endpoints::from(endpoints),
+        cmd_line: "mrf-authoritative-test".to_string(),
+        platform: String::new(),
+    };
+    init_local_disks(EndpointServerPools::from(vec![pool]))
+        .await
+        .expect("local disks should register");
+
+    let authoritative = journal_record(1, "authoritative-bucket", "authoritative-object", None, 0);
+    let legacy = journal_record(1, "legacy-bucket", "legacy-object", None, 0);
+    write_journal_path_to_disks(&disk_paths, SCOPED_JOURNAL_REL, &authoritative);
+    write_journal_path_to_disks(&disk_paths, JOURNAL_REL, &legacy);
+
+    let manager = make_manager(storage);
+    let replayed = mrf_queue::replay_journal_once(&manager).await;
+    assert_eq!(replayed, 1, "only the authoritative snapshot epoch may replay");
+
+    let snapshot = manager.operations_snapshot().await;
+    assert_eq!(snapshot.queued_by_source.mrf, 1);
+    assert!(
+        disk_paths.iter().all(|path| {
+            !Path::new(path).join(META_BUCKET).join(JOURNAL_REL).exists()
+                && !Path::new(path).join(META_BUCKET).join(SCOPED_JOURNAL_REL).exists()
+        }),
+        "replay cleanup must remove both journal paths"
+    );
+
+    // A scoped-only snapshot is valid during a rollout where no legacy
+    // compatibility mirror was written. Missing legacy files must not leave
+    // the runtime in a permanent cleanup-retry state.
+    let scoped_only = journal_record(1, "scoped-only-bucket", "scoped-only-object", None, 0);
+    write_journal_path_to_disks(&disk_paths, SCOPED_JOURNAL_REL, &scoped_only);
+    assert_eq!(mrf_queue::replay_journal_once(&manager).await, 1);
+    assert!(disk_paths.iter().all(|path| {
+        !Path::new(path).join(META_BUCKET).join(JOURNAL_REL).exists()
+            && !Path::new(path).join(META_BUCKET).join(SCOPED_JOURNAL_REL).exists()
+    }));
+}
@@ -16,14 +16,14 @@
 //!
 //! `scripts/test/vault_ha_kms_live.sh` owns the official Vault containers and
 //! kills the active node while this test continuously decrypts through a
-//! surviving standby. KV2 and Transit must recover after the bounded circuit
-//! interval, use a bounded number of attempts, and leave the circuit and
-//! in-flight gauges at zero after a new leader is elected.
+//! surviving standby. KV2 and Transit requests must remain successful, use a
+//! bounded number of attempts, and leave the circuit and in-flight gauges at
+//! zero after a new leader is elected.

 use std::collections::HashMap;
 use std::path::{Path, PathBuf};
+use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
-use std::sync::{Arc, Mutex};
 use std::time::Duration;

 use metrics_util::MetricKind;
@@ -43,11 +43,6 @@ const OPERATION_ATTEMPTS: &str = "rustfs_kms_backend_operation_attempts";
 const IN_FLIGHT: &str = "rustfs_kms_backend_in_flight";
 const CIRCUIT_OPEN: &str = "rustfs_kms_backend_circuit_open";
 const MAX_ATTEMPTS: u32 = 10;
-const ATTEMPT_TIMEOUT: Duration = Duration::from_secs(2);
-const HEALTHY_PROGRESS_TIMEOUT: Duration = Duration::from_secs(20);
-// The circuit remains open for 30s after five failed attempts.
-const POST_FAILOVER_PROGRESS_TIMEOUT: Duration = Duration::from_secs(35);
-const FAILOVER_ERROR_POLL_INTERVAL: Duration = Duration::from_millis(100);

 type MetricEntry = (
    metrics_util::CompositeKey,
@@ -69,7 +64,7 @@ fn config(backend: KmsBackend, backend_config: BackendConfig) -> KmsConfig {
        backend,
        backend_config,
        allow_insecure_dev_defaults: true,
-        timeout: ATTEMPT_TIMEOUT,
+        timeout: Duration::from_secs(2),
        retry_attempts: MAX_ATTEMPTS,
        enable_cache: false,
        ..KmsConfig::default()
@@ -169,31 +164,14 @@ fn retryable_failures(snapshot: &[MetricEntry], operation: &str) -> u64 {
        .sum()
 }

-async fn wait_for_count(
-    counter: &AtomicU64,
-    failure: &Mutex<Option<String>>,
-    minimum: u64,
-    description: &str,
-    timeout: Duration,
-) {
-    tokio::time::timeout(timeout, async {
+async fn wait_for_count(counter: &AtomicU64, minimum: u64, description: &str) {
+    tokio::time::timeout(Duration::from_secs(20), async {
        while counter.load(Ordering::SeqCst) < minimum {
-            if let Some(error) = failure.lock().expect("decrypt failure lock poisoned").as_ref() {
-                panic!(
-                    "{description} worker failed after {} successful decrypts: {error}",
-                    counter.load(Ordering::SeqCst)
-                );
-            }
            tokio::time::sleep(Duration::from_millis(25)).await;
        }
    })
    .await
-    .unwrap_or_else(|_| {
-        panic!(
-            "timed out after {timeout:?} waiting for {description}: completed {}, expected {minimum}",
-            counter.load(Ordering::SeqCst)
-        )
-    });
+    .unwrap_or_else(|_| panic!("timed out waiting for {description}"));
 }

 async fn wait_for_file(path: &Path, description: &str) {
@@ -211,8 +189,7 @@ async fn decrypt_loop<B: KmsBackendTrait + Send + Sync + 'static>(
    request: DecryptRequest,
    expected: Vec<u8>,
    completed: Arc<AtomicU64>,
-    allow_failover_errors: Arc<AtomicBool>,
-    failure: Arc<Mutex<Option<String>>>,
+    failed: Arc<AtomicBool>,
    stop: CancellationToken,
 ) {
    while !stop.is_cancelled() {
@@ -220,18 +197,8 @@ async fn decrypt_loop<B: KmsBackendTrait + Send + Sync + 'static>(
            Ok(response) if response.plaintext == expected => {
                completed.fetch_add(1, Ordering::SeqCst);
            }
-            Ok(_) => {
-                *failure.lock().expect("decrypt failure lock poisoned") =
-                    Some("decrypt returned unexpected plaintext".to_string());
-                return;
-            }
-            Err(rustfs_kms::KmsError::BackendError { .. } | rustfs_kms::KmsError::OperationTimedOut { .. })
-                if allow_failover_errors.load(Ordering::SeqCst) =>
-            {
-                tokio::time::sleep(FAILOVER_ERROR_POLL_INTERVAL).await;
-            }
-            Err(error) => {
-                *failure.lock().expect("decrypt failure lock poisoned") = Some(error.to_string());
+            Ok(_) | Err(_) => {
+                failed.store(true, Ordering::SeqCst);
                return;
            }
        }
@@ -329,9 +296,7 @@ async fn exercise_failover(snapshotter: &Snapshotter) {
    );

    let stop = CancellationToken::new();
-    let allow_failover_errors = Arc::new(AtomicBool::new(false));
-    let kv2_failure = Arc::new(Mutex::new(None));
-    let transit_failure = Arc::new(Mutex::new(None));
+    let failed = Arc::new(AtomicBool::new(false));
    let kv2_completed = Arc::new(AtomicU64::new(0));
    let transit_completed = Arc::new(AtomicU64::new(0));
    let kv2_worker = tokio::spawn(decrypt_loop(
@@ -339,8 +304,7 @@ async fn exercise_failover(snapshotter: &Snapshotter) {
        kv2_request,
        kv2_data_key.plaintext_key,
        Arc::clone(&kv2_completed),
-        Arc::clone(&allow_failover_errors),
-        Arc::clone(&kv2_failure),
+        Arc::clone(&failed),
        stop.clone(),
    ));
    let transit_worker = tokio::spawn(decrypt_loop(
@@ -348,21 +312,12 @@ async fn exercise_failover(snapshotter: &Snapshotter) {
        transit_request,
        transit_data_key.plaintext_key,
        Arc::clone(&transit_completed),
-        Arc::clone(&allow_failover_errors),
-        Arc::clone(&transit_failure),
+        Arc::clone(&failed),
        stop.clone(),
    ));

-    wait_for_count(&kv2_completed, &kv2_failure, 2, "two healthy KV2 decrypts", HEALTHY_PROGRESS_TIMEOUT).await;
-    wait_for_count(
-        &transit_completed,
-        &transit_failure,
-        2,
-        "two healthy Transit decrypts",
-        HEALTHY_PROGRESS_TIMEOUT,
-    )
-    .await;
-    allow_failover_errors.store(true, Ordering::SeqCst);
+    wait_for_count(&kv2_completed, 2, "two healthy KV2 decrypts").await;
+    wait_for_count(&transit_completed, 2, "two healthy Transit decrypts").await;
    std::fs::write(&marker, b"ready").expect("publish failover readiness marker");

    wait_for_file(&elected, "the replacement Vault leader").await;
@@ -371,39 +326,18 @@ async fn exercise_failover(snapshotter: &Snapshotter) {

    let kv2_after_election = kv2_completed.load(Ordering::SeqCst) + 2;
    let transit_after_election = transit_completed.load(Ordering::SeqCst) + 2;
-    wait_for_count(
-        &kv2_completed,
-        &kv2_failure,
-        kv2_after_election,
-        "post-failover KV2 decrypts",
-        POST_FAILOVER_PROGRESS_TIMEOUT,
-    )
-    .await;
-    wait_for_count(
-        &transit_completed,
-        &transit_failure,
-        transit_after_election,
-        "post-failover Transit decrypts",
-        POST_FAILOVER_PROGRESS_TIMEOUT,
-    )
-    .await;
+    wait_for_count(&kv2_completed, kv2_after_election, "post-failover KV2 decrypts").await;
+    wait_for_count(&transit_completed, transit_after_election, "post-failover Transit decrypts").await;

    stop.cancel();
    kv2_worker.await.expect("KV2 decrypt worker must join");
    transit_worker.await.expect("Transit decrypt worker must join");
-    assert!(
-        kv2_failure.lock().expect("KV2 failure lock poisoned").is_none(),
-        "no KV2 decrypt may fail or return different plaintext"
-    );
-    assert!(
-        transit_failure.lock().expect("Transit failure lock poisoned").is_none(),
-        "no Transit decrypt may fail or return different plaintext"
-    );
+    assert!(!failed.load(Ordering::SeqCst), "no decrypt may fail or return different plaintext");
 }

 #[test]
 #[ignore = "requires a real three-node Vault Raft cluster; run scripts/test/vault_ha_kms_live.sh"]
-fn vault_raft_leader_failure_recovers_kv2_and_transit_decrypts() {
+fn vault_raft_leader_failure_preserves_kv2_and_transit_decrypts() {
    let recorder = DebuggingRecorder::new();
    let snapshotter = recorder.snapshotter();
    metrics::with_local_recorder(&recorder, || {
@@ -415,6 +349,11 @@ fn vault_raft_leader_failure_recovers_kv2_and_transit_decrypts() {
    });
    let snapshot = snapshotter.snapshot().into_vec();

+    assert_eq!(
+        counter_value(&snapshot, OPERATIONS_TOTAL, &[("outcome", "circuit_open")]),
+        0,
+        "a bounded leader election must not open the circuit"
+    );
    assert_eq!(
        counter_value(&snapshot, OPERATIONS_TOTAL, &[("outcome", "budget_exhausted")]),
        0,
@@ -29,8 +29,7 @@ use rustfs_config::ENV_SCANNER_CACHE_SAVE_TIMEOUT_SECS;
 pub use rustfs_data_usage::{
    AllTierStats, BucketTargetUsageInfo, BucketUsageInfo, DATA_USAGE_OBJECT_NAME, DATA_USAGE_OBSERVED_OBJECT_NAME,
    DataUsageEntry, DataUsageHash, DataUsageHashMap, DataUsageInfo, LEGACY_DATA_USAGE_OBJECT_NAME, PrefixUsageEntry,
-    PrefixUsageQuery, PrefixUsageSummary, ReplTargetSizeSummary, SizeSummary, TierAccountingProof, TierStats, UNKNOWN_TIER,
-    UNKNOWN_TIER_DIAGNOSTIC_BYTE_CAP, UNKNOWN_TIER_DIAGNOSTIC_ENTRY_CAP, UnknownTierStats, hash_path, prefix_usage_in_cache,
+    PrefixUsageQuery, PrefixUsageSummary, ReplTargetSizeSummary, SizeSummary, TierStats, hash_path, prefix_usage_in_cache,
 };
 use rustfs_utils::path::{SLASH_SEPARATOR, path_join_buf};
 use tokio::time::{Duration, Instant, sleep, timeout};
@@ -206,79 +205,25 @@ impl ScannerSizeSummaryExt for SizeSummary {
            self.versions = self.versions.saturating_add(1);
        }

-        let logical_size = size.max(0);
-        let size = usize::try_from(logical_size).unwrap_or(usize::MAX);
+        let size = usize::try_from(size.max(0)).unwrap_or(usize::MAX);
        self.total_size = self.total_size.saturating_add(size);
-        let logical_bytes = u64::try_from(logical_size).unwrap_or(u64::MAX);
-        let physical_bytes = u64::try_from(oi.size.max(0)).unwrap_or(0);
-        let mut proof = TierAccountingProof {
-            logical_total: logical_bytes,
-            logical_known: 0,
-            physical_total: physical_bytes,
-            physical_known: 0,
-            overflowed: false,
-        };

        if oi.transitioned_object.free_version {
-            proof.logical_known = logical_bytes;
-            proof.physical_known = physical_bytes;
-            self.tier_accounting_proof.saturating_add(proof);
            return;
        }

-        let tier = if oi.transitioned_object.status == TRANSITION_COMPLETE {
-            oi.transitioned_object.tier.as_str()
-        } else {
-            oi.storage_class.as_deref().unwrap_or(storageclass::STANDARD)
-        };
-
-        let builtin_tier = tier == storageclass::STANDARD || tier == storageclass::RRS;
-        let tier_registry_is_empty =
-            self.tier_stats.is_empty() || (self.tier_stats.len() == 1 && self.tier_stats.contains_key(UNKNOWN_TIER));
-        let known_tier = tier != UNKNOWN_TIER && (builtin_tier || self.tier_stats.contains_key(tier));
-
-        // With no configured tier, retain the historical empty-map shape for
-        // ordinary STANDARD/RRS objects. A non-built-in key is still an
-        // observable unknown and must create only the fixed bucket.
-        if tier_registry_is_empty && known_tier {
-            proof.logical_known = logical_bytes;
-            proof.physical_known = physical_bytes;
-            self.tier_accounting_proof.saturating_add(proof);
-            return;
+        let mut tier = oi.storage_class.clone().unwrap_or_else(|| storageclass::STANDARD.to_string());
+        if oi.transitioned_object.status == TRANSITION_COMPLETE {
+            tier = oi.transitioned_object.tier.clone();
        }

-        // Configured tiers and the fixed bucket are normally seeded, so the
-        // hot path can mutate them without allocating a key for every object.
-        // The fallback inserts only when a legacy/no-config summary sees its
-        // first unknown key.
-        let tier_stats = if known_tier {
-            if let Some(stats) = self.tier_stats.get_mut(tier) {
-                stats
-            } else {
-                self.tier_stats.entry(tier.to_owned()).or_default()
-            }
-        } else if let Some(stats) = self.tier_stats.get_mut(UNKNOWN_TIER) {
-            stats
-        } else {
-            self.tier_stats.entry(UNKNOWN_TIER.to_string()).or_default()
-        };
-        *tier_stats = tier_stats.add(&TierStats {
-            total_size: physical_bytes,
-            num_versions: 1,
-            num_objects: u64::from(oi.is_latest),
-        });
-        if known_tier {
-            proof.logical_known = logical_bytes;
-            proof.physical_known = physical_bytes;
+        if let Some(tier_stats) = self.tier_stats.get_mut(&tier) {
+            *tier_stats = tier_stats.add(&TierStats {
+                total_size: u64::try_from(oi.size).unwrap_or(0),
+                num_versions: 1,
+                num_objects: u64::from(oi.is_latest),
+            });
        }
-        if !known_tier {
-            self.unknown_tier_stats
-                .record_dimensions(tier, logical_bytes, physical_bytes, 1, u64::from(oi.is_latest));
-            if self.unknown_tier_stats.counter_overflowed {
-                proof.overflowed = true;
-            }
-        }
-        self.tier_accounting_proof.saturating_add(proof);
    }
 }

@@ -326,11 +271,6 @@ pub struct DataUsageEntryInfo {
    pub name: String,
    pub parent: String,
    pub entry: DataUsageEntry,
-    /// Registry generation used to classify this root entry. Older remote
-    /// workers omit it; callers must reject that result when a frozen cycle
-    /// requires generation fencing.
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub tier_registry_generation: Option<u64>,
 }

 #[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq, Eq, Hash)]
@@ -404,10 +344,6 @@ pub struct DataUsageCacheInfo {
    pub scan_plan_digest: Option<DataUsageScanPlanDigest>,
    #[serde(default)]
    pub cache_key_format: u16,
-    /// Registry generation used for the completed/partial scan. This is
-    /// process-local audit data; older cache writers omit it.
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub tier_registry_generation: Option<u64>,
 }

 impl Serialize for DataUsageCacheInfo {
@@ -417,8 +353,7 @@ impl Serialize for DataUsageCacheInfo {
    {
        // Keep this metadata map-encoded so older readers can ignore fields
        // appended by newer scanner versions during rolling upgrades.
-        let field_count = 16 + usize::from(self.tier_registry_generation.is_some());
-        let mut state = serializer.serialize_map(Some(field_count))?;
+        let mut state = serializer.serialize_map(Some(16))?;
        state.serialize_entry("name", &self.name)?;
        state.serialize_entry("next_cycle", &self.next_cycle)?;
        state.serialize_entry("leader_epoch", &self.leader_epoch)?;
@@ -435,9 +370,6 @@ impl Serialize for DataUsageCacheInfo {
        state.serialize_entry("snapshot_complete", &self.snapshot_complete)?;
        state.serialize_entry("scan_plan_digest", &self.scan_plan_digest)?;
        state.serialize_entry("cache_key_format", &self.cache_key_format)?;
-        if let Some(generation) = self.tier_registry_generation {
-            state.serialize_entry("tier_registry_generation", &generation)?;
-        }
        state.end()
    }
 }
@@ -458,58 +390,6 @@ pub(crate) enum DataUsageCachePrepareOutcome {
 }

 impl DataUsageCache {
-    /// Reconcile tier keys loaded from an older cache against the registry
-    /// frozen for this scan. New metadata is already routed through
-    /// `UNKNOWN_TIER`; this pass handles retired keys that predate that rule.
-    /// Legacy `TierStats` carries physical bytes only, so this migration does
-    /// not manufacture a logical unknown-byte value from that physical total.
-    pub(crate) fn fold_retired_tiers(&mut self, tier_names: &[String]) {
-        let known_tiers = tier_names.iter().map(String::as_str).collect::<HashSet<_>>();
-        for entry in self.cache.values_mut() {
-            let Some(tiers) = entry.all_tier_stats.as_mut() else { continue };
-            let existing_unknown = tiers.tiers.get(UNKNOWN_TIER).cloned().unwrap_or_default();
-            let companion_present = entry.unknown_tier_stats.as_ref().is_some_and(|stats| !stats.is_empty());
-            let migrate_existing_unknown = !companion_present;
-            let mut retired = TierStats::default();
-            let mut retired_key_found = false;
-            if migrate_existing_unknown {
-                retired = retired.add(&existing_unknown);
-            }
-            for (tier, stats) in &tiers.tiers {
-                if tier != UNKNOWN_TIER
-                    && tier != storageclass::STANDARD
-                    && tier != storageclass::RRS
-                    && !known_tiers.contains(tier.as_str())
-                {
-                    retired_key_found = true;
-                    retired = retired.add(stats);
-                }
-            }
-            tiers.fold_unknown_tiers(tier_names.iter().map(String::as_str));
-            if !retired.is_empty() && !companion_present {
-                entry.add_unknown_tier_stats(&UnknownTierStats {
-                    // The legacy map stores physical bytes only. Logical
-                    // bytes remain zero until a fresh object scan observes
-                    // them under the current metadata format.
-                    unknown_physical_bytes: retired.total_size,
-                    unknown_objects: retired.num_objects,
-                    unknown_versions: retired.num_versions,
-                    ..Default::default()
-                });
-                // The legacy tier map has no logical-byte dimension, so a
-                // proof that classified this retired key as known cannot be
-                // repaired safely. Mark it unvalidated and require a fresh
-                // scan rather than guessing a logical subtraction.
-                entry.tier_accounting_proof = None;
-            } else if retired_key_found {
-                // A nonempty companion has no provenance tying it to the
-                // retired map keys. Reject the mixed cache until a fresh scan
-                // reconciles the dimensions instead of double-counting them.
-                entry.tier_accounting_proof = None;
-            }
-        }
-    }
-
    /// Prefix-level usage query over this (writer-side) cache; see
    /// [`prefix_usage_in_cache`] for the semantics
    /// (rustfs/backlog#1872).
@@ -995,7 +875,6 @@ impl DataUsageCache {
            delete_markers_total_count: flat.delete_markers as u64,
            objects_total_size: flat.size as u64,
            tier_stats: flat.all_tier_stats.filter(|tiers| !tiers.is_empty()),
-            unknown_tier_stats: flat.unknown_tier_stats.filter(|stats| !stats.is_empty()),
            buckets_count: u64::try_from(buckets.len()).unwrap_or(u64::MAX),
            buckets_usage,
            ..Default::default()
@@ -573,6 +573,7 @@ fn size_summary_add_saturates_all_usage_counters() {
            failed_count: usize::MAX,
        },
    );
+
    let mut increment = SizeSummary {
        total_size: 1,
        versions: 1,
@@ -587,24 +588,6 @@ fn size_summary_add_saturates_all_usage_counters() {
        failed_count: 1,
        ..Default::default()
    };
-    summary.tier_stats.insert(
-        UNKNOWN_TIER.to_string(),
-        TierStats {
-            total_size: u64::MAX,
-            num_versions: u64::MAX,
-            num_objects: u64::MAX,
-        },
-    );
-    increment.tier_stats.insert(
-        UNKNOWN_TIER.to_string(),
-        TierStats {
-            total_size: 1,
-            num_versions: 1,
-            num_objects: 1,
-        },
-    );
-    increment.unknown_tier_stats.unknown_bytes = 1;
-    increment.unknown_tier_stats.unknown_physical_bytes = 1;
    increment.repl_target_stats.insert(
        target.clone(),
        ReplTargetSizeSummary {
@@ -641,8 +624,6 @@ fn size_summary_add_saturates_all_usage_counters() {
    assert_eq!(target_summary.failed_size, i64::MAX);
    assert_eq!(target_summary.pending_count, usize::MAX);
    assert_eq!(target_summary.failed_count, usize::MAX);
-    assert_eq!(summary.tier_stats[UNKNOWN_TIER].total_size, u64::MAX);
-    assert_eq!(summary.unknown_tier_stats.unknown_bytes, 1);
 }

 #[test]
@@ -692,249 +673,6 @@ fn size_summary_actions_accounting_accumulates_tier_stats() {
    );
 }

-#[test]
-fn unknown_tier_is_bounded_and_accounted() {
-    let mut summary = SizeSummary::new();
-    summary.tier_stats.insert("WARM".to_string(), TierStats::default());
-    let object = ObjectInfo {
-        storage_class: Some("retired-tier".to_string()),
-        size: 11,
-        is_latest: true,
-        ..Default::default()
-    };
-
-    summary.actions_accounting(&object, 11, 11);
-
-    assert_eq!(summary.tier_stats.len(), 2);
-    assert_eq!(summary.tier_stats.get(UNKNOWN_TIER).map(|stats| stats.total_size), Some(11));
-    assert_eq!(summary.unknown_tier_stats.unknown_bytes, 11);
-    assert_eq!(summary.unknown_tier_stats.unknown_physical_bytes, 11);
-    assert_eq!(summary.unknown_tier_stats.unknown_objects, 1);
-    assert_eq!(summary.tier_accounting_proof.logical_total, 11);
-    assert_eq!(summary.tier_accounting_proof.logical_known, 0);
-    assert_eq!(summary.tier_accounting_proof.physical_total, 11);
-    assert_eq!(summary.tier_accounting_proof.physical_known, 0);
-    assert!(summary.unknown_tier_stats.diagnostics.len() <= UNKNOWN_TIER_DIAGNOSTIC_ENTRY_CAP);
-    assert!(summary.unknown_tier_stats.diagnostics.iter().map(String::len).sum::<usize>() <= UNKNOWN_TIER_DIAGNOSTIC_BYTE_CAP);
-    assert!(
-        summary
-            .unknown_tier_stats
-            .diagnostics
-            .iter()
-            .all(|entry| !entry.contains("retired"))
-    );
-}
-
-#[test]
-fn unknown_tier_is_accounted_when_no_remote_tier_is_configured() {
-    let mut summary = SizeSummary::new();
-    let object = ObjectInfo {
-        storage_class: Some("retired-tier".to_string()),
-        size: 3,
-        is_latest: true,
-        ..Default::default()
-    };
-
-    summary.actions_accounting(&object, 9, 9);
-
-    assert_eq!(summary.tier_stats.len(), 1);
-    assert_eq!(summary.tier_stats[UNKNOWN_TIER].total_size, 3);
-    assert_eq!(summary.unknown_tier_stats.unknown_bytes, 9);
-    assert_eq!(summary.unknown_tier_stats.unknown_physical_bytes, 3);
-
-    let standard = ObjectInfo {
-        storage_class: Some(storageclass::STANDARD.to_string()),
-        size: 4,
-        is_latest: true,
-        ..Default::default()
-    };
-    summary.actions_accounting(&standard, 4, 4);
-    assert_eq!(summary.tier_accounting_proof.logical_total, 13);
-    assert_eq!(summary.tier_accounting_proof.logical_known, 4);
-    assert_eq!(summary.tier_accounting_proof.physical_total, 3 + 4);
-    assert_eq!(summary.tier_accounting_proof.physical_known, 4);
-    assert_eq!(summary.tier_stats.len(), 1, "built-ins preserve the no-tier map shape");
-}
-
-#[test]
-fn million_unique_tier_keys_do_not_grow_stats_map() {
-    let mut summary = SizeSummary::new();
-    summary.tier_stats.insert("WARM".to_string(), TierStats::default());
-    for index in 0..1_000_000_u64 {
-        let object = ObjectInfo {
-            storage_class: Some(format!("untrusted-tier-{index}")),
-            size: 1,
-            ..Default::default()
-        };
-        summary.actions_accounting(&object, 1, 1);
-    }
-
-    assert_eq!(summary.tier_stats.len(), 2);
-    assert_eq!(summary.tier_stats[UNKNOWN_TIER].total_size, 1_000_000);
-    assert_eq!(summary.unknown_tier_stats.unknown_bytes, 1_000_000);
-    assert!(summary.unknown_tier_stats.diagnostics.len() <= UNKNOWN_TIER_DIAGNOSTIC_ENTRY_CAP);
-    assert!(summary.unknown_tier_stats.diagnostics.iter().map(String::len).sum::<usize>() <= UNKNOWN_TIER_DIAGNOSTIC_BYTE_CAP);
-}
-
-#[test]
-fn unknown_tier_never_triggers_transition() {
-    let mut summary = SizeSummary::new();
-    summary.tier_stats.insert("WARM".to_string(), TierStats::default());
-    let mut object = ObjectInfo {
-        storage_class: Some("removed-tier".to_string()),
-        size: 7,
-        ..Default::default()
-    };
-    object.transitioned_object.status = TRANSITION_COMPLETE.to_string();
-    object.transitioned_object.tier = "removed-tier".to_string();
-
-    summary.actions_accounting(&object, 7, 7);
-
-    assert_eq!(summary.tier_stats.get("removed-tier"), None);
-    assert_eq!(summary.tier_stats[UNKNOWN_TIER].total_size, 7);
-}
-
-#[test]
-fn removed_tier_survives_restart_as_unknown() {
-    let mut summary = SizeSummary::new();
-    summary.tier_stats.insert("COLD".to_string(), TierStats::default());
-    summary.tier_stats.insert(
-        "RETIRED".to_string(),
-        TierStats {
-            total_size: 5,
-            num_versions: 1,
-            num_objects: 1,
-        },
-    );
-    let object = ObjectInfo {
-        storage_class: Some("COLD".to_string()),
-        size: 5,
-        ..Default::default()
-    };
-    summary.actions_accounting(&object, 5, 5);
-    let mut entry = DataUsageEntry::default();
-    entry.add_tier_sizes(&summary.tier_stats);
-    entry.add_unknown_tier_stats(&UnknownTierStats {
-        unknown_bytes: 2,
-        unknown_physical_bytes: 2,
-        unknown_objects: 1,
-        unknown_versions: 1,
-        ..Default::default()
-    });
-    let encoded = rmp_serde::to_vec(&entry).expect("entry should encode");
-    let restored: DataUsageEntry = rmp_serde::from_slice(&encoded).expect("entry should decode");
-    assert_eq!(restored.unknown_tier_stats.as_ref().map(|stats| stats.unknown_bytes), Some(2));
-    assert_eq!(
-        restored.all_tier_stats.as_ref().expect("tier stats persisted").tiers["RETIRED"].total_size,
-        5
-    );
-
-    let mut cache = DataUsageCache::default();
-    cache.replace("bucket", "", restored);
-    cache.fold_retired_tiers(&["COLD".to_string()]);
-    let folded = cache.cache.get(&hash_path("bucket").key()).expect("folded cache entry");
-    assert_eq!(
-        folded.all_tier_stats.as_ref().expect("tier stats persisted").tiers[UNKNOWN_TIER].total_size,
-        5
-    );
-    assert_eq!(folded.unknown_tier_stats.as_ref().map(|stats| stats.unknown_bytes), Some(2));
-}
-
-#[test]
-fn retired_tier_fold_is_idempotent_and_rejects_mixed_companion_provenance() {
-    let mut cache = DataUsageCache::default();
-    let mut entry = DataUsageEntry {
-        all_tier_stats: Some(AllTierStats {
-            tiers: HashMap::from([(
-                "RETIRED".to_string(),
-                TierStats {
-                    total_size: 5,
-                    num_versions: 1,
-                    num_objects: 1,
-                },
-            )]),
-        }),
-        ..Default::default()
-    };
-    entry.unknown_tier_stats = Some(UnknownTierStats {
-        unknown_physical_bytes: 5,
-        ..Default::default()
-    });
-    entry.tier_accounting_proof = Some(TierAccountingProof {
-        physical_total: 5,
-        physical_known: 5,
-        ..Default::default()
-    });
-    cache.replace("bucket", "", entry);
-
-    cache.fold_retired_tiers(&["COLD".to_string()]);
-    let first = cache.cache.get(&hash_path("bucket").key()).expect("entry").clone();
-    assert_eq!(first.all_tier_stats.as_ref().expect("tiers").tiers[UNKNOWN_TIER].total_size, 5);
-    assert_eq!(first.unknown_tier_stats.as_ref().expect("companion").unknown_physical_bytes, 5);
-    assert!(first.tier_accounting_proof.is_none(), "mixed provenance must not publish");
-
-    cache.fold_retired_tiers(&["COLD".to_string()]);
-    let second = cache.cache.get(&hash_path("bucket").key()).expect("entry");
-    assert_eq!(second.all_tier_stats.as_ref().expect("tiers").tiers[UNKNOWN_TIER].total_size, 5);
-    assert_eq!(second.unknown_tier_stats.as_ref().expect("companion").unknown_physical_bytes, 5);
-}
-
-#[test]
-fn tier_registry_refresh_does_not_mix_cycle_generations() {
-    let first = crate::TierRegistrySnapshot {
-        generation: 1,
-        names: Arc::from(["WARM".to_string()]),
-        refresh_failed: false,
-    };
-    let second = crate::TierRegistrySnapshot {
-        generation: 2,
-        names: Arc::from(["COLD".to_string()]),
-        refresh_failed: false,
-    };
-    assert_ne!(first.generation, second.generation);
-    assert_eq!(first.names.as_ref(), ["WARM".to_string()]);
-    assert_eq!(second.names.as_ref(), ["COLD".to_string()]);
-    assert!(first.refreshed(Err(())).refresh_failed);
-    assert!(!second.refreshed(Ok(Arc::from(["HOT".to_string()]))).refresh_failed);
-    assert_eq!(first.refreshed(Err(())).generation, first.generation);
-    assert_eq!(first.refreshed(Err(())).names, first.names);
-}
-
-#[test]
-fn unknown_tier_counter_uses_checked_arithmetic() {
-    let max = TierStats {
-        total_size: u64::MAX,
-        num_versions: u64::MAX,
-        num_objects: u64::MAX,
-    };
-    assert!(max.checked_add(&TierStats::default()).is_some());
-    assert!(
-        max.checked_add(&TierStats {
-            total_size: 1,
-            ..Default::default()
-        })
-        .is_none()
-    );
-
-    let mut unknown = UnknownTierStats {
-        unknown_bytes: u64::MAX,
-        ..Default::default()
-    };
-    unknown.record("overflow", 1, 1, 1);
-    assert_eq!(unknown.unknown_bytes, u64::MAX);
-    assert_eq!(unknown.unknown_objects, 1);
-    assert!(unknown.counter_overflowed);
-    assert!(unknown.checked_add(&UnknownTierStats::default()).is_none());
-    assert!(
-        unknown
-            .checked_add(&UnknownTierStats {
-                unknown_bytes: 1,
-                ..Default::default()
-            })
-            .is_none()
-    );
-}
-
 #[test]
 fn test_data_usage_entry_merge_sums_failed_objects() {
    let mut left = DataUsageEntry {
@@ -24,11 +24,8 @@
 use bytes::Bytes;
 use http::HeaderMap;
 use rustfs_config::server_config::{Config as ServerConfig, get_global_server_config as config_get_global_server_config};
-use sha2::{Digest as _, Sha256};
-use std::collections::HashMap;
 use std::path::PathBuf;
 use std::sync::Arc;
-use std::sync::LazyLock;
 use std::sync::RwLock;
 use std::time::{Duration, Instant};
 use storage_api::owner::{
@@ -97,45 +94,6 @@ static SCANNER_RUNTIME_INSTANCES: AtomicU64 = AtomicU64::new(0);
 static SCANNER_FOREGROUND_READ_ACTIVITY: AtomicU64 = AtomicU64::new(0);
 static SCANNER_FOREGROUND_STREAM_READS: AtomicU64 = AtomicU64::new(0);

-/// Immutable tier registry captured at the beginning of a folder scan.
-/// Generation makes it possible to prove that a result was classified against
-/// one registry even when the process-wide TTL cache refreshes concurrently.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) struct TierRegistrySnapshot {
-    pub(crate) generation: u64,
-    pub(crate) names: Arc<[String]>,
-    /// True when the last refresh attempt failed and `names` is therefore a
-    /// retained last-good snapshot rather than a newly read registry.
-    pub(crate) refresh_failed: bool,
-}
-
-impl TierRegistrySnapshot {
-    /// Apply a refresh only when the registry read succeeds. A failed refresh
-    /// retains the prior generation, preventing a transient config failure
-    /// from classifying the remainder of a scan against an empty registry.
-    pub(crate) fn refreshed(&self, names: Result<Arc<[String]>, ()>) -> Self {
-        match names {
-            Ok(names) => Self {
-                generation: self.generation.saturating_add(1),
-                names,
-                refresh_failed: false,
-            },
-            Err(()) => Self {
-                refresh_failed: true,
-                ..self.clone()
-            },
-        }
-    }
-
-    pub(crate) fn initial(names: Arc<[String]>) -> Self {
-        Self {
-            generation: 1,
-            names,
-            refresh_failed: false,
-        }
-    }
-}
-
 pub fn current_scanner_activity() -> u64 {
    SCANNER_ACTIVE_WORK_UNITS.load(Ordering::Relaxed)
 }
@@ -413,7 +371,6 @@ pub(crate) fn resolve_scanner_server_config() -> Option<ServerConfig> {
 /// How long the scanner caches the runtime tier-name list before re-reading
 /// the tier configuration manager.
 const TIER_NAME_CACHE_TTL: Duration = Duration::from_secs(30);
-const MAX_TIER_REGISTRY_NAME_BYTES: usize = 256;

 /// Process-wide TTL cache of runtime tier names.
 ///
@@ -426,192 +383,24 @@ const MAX_TIER_REGISTRY_NAME_BYTES: usize = 256;
 /// `TIER_NAME_CACHE_TTL` later; a removed tier can leave an all-zero
 /// `TierStats` seed behind for one cache generation, which merges harmlessly
 /// by key in per-object accounting and disappears on the next refresh.
-static TIER_NAME_CACHE: RwLock<Option<(Instant, TierRegistrySnapshot)>> = RwLock::new(None);
-static TIER_REGISTRY_GENERATION: AtomicU64 = AtomicU64::new(0);
-static TIER_CYCLE_SNAPSHOTS: LazyLock<RwLock<HashMap<(u64, u64), TierRegistrySnapshot>>> =
-    LazyLock::new(|| RwLock::new(HashMap::new()));
-static TIER_ACTIVE_CYCLES: LazyLock<RwLock<HashMap<(u64, u64), usize>>> = LazyLock::new(|| RwLock::new(HashMap::new()));
-static TIER_NAME_REFRESH_LOCK: LazyLock<tokio::sync::Mutex<()>> = LazyLock::new(|| tokio::sync::Mutex::new(()));
-
-/// Return one immutable registry snapshot for a scanner unit of work.
-pub(crate) async fn runtime_tier_registry() -> TierRegistrySnapshot {
-    {
-        let cached = TIER_NAME_CACHE.read().unwrap_or_else(|err| err.into_inner()).clone();
-        if let Some((refreshed_at, snapshot)) = cached
-            && refreshed_at.elapsed() < TIER_NAME_CACHE_TTL
-        {
-            return snapshot;
-        }
-    }
-
-    // Serialize refreshes so a slower read of the old config cannot overwrite
-    // a newer snapshot published by a concurrent caller.
-    let _refresh_guard = TIER_NAME_REFRESH_LOCK.lock().await;
-    {
-        let cached = TIER_NAME_CACHE.read().unwrap_or_else(|err| err.into_inner()).clone();
-        if let Some((refreshed_at, snapshot)) = cached
-            && refreshed_at.elapsed() < TIER_NAME_CACHE_TTL
-        {
-            return snapshot;
-        }
-    }
-
-    let previous = TIER_NAME_CACHE
-        .read()
-        .unwrap_or_else(|err| err.into_inner())
-        .as_ref()
-        .map(|(_, snapshot)| snapshot.clone());
-    let names = ecstore_get_global_tier_config_mgr()
-        .read()
-        .await
-        .list_tiers()
-        .into_iter()
-        .map(|tier| tier.name)
-        .collect::<Vec<_>>();
-    let snapshot = match validate_tier_registry_names(names) {
-        Ok(names) => {
-            let generation = next_tier_registry_generation();
-            match previous {
-                Some(previous) => TierRegistrySnapshot {
-                    generation,
-                    ..previous.refreshed(Ok(names))
-                },
-                None => TierRegistrySnapshot {
-                    generation,
-                    ..TierRegistrySnapshot::initial(names)
-                },
-            }
-        }
-        Err(()) => match previous {
-            Some(previous) => previous.refreshed(Err(())),
-            None => TierRegistrySnapshot {
-                generation: next_tier_registry_generation(),
-                names: Arc::new([]),
-                refresh_failed: true,
-            },
-        },
-    };
-    *TIER_NAME_CACHE.write().unwrap_or_else(|err| err.into_inner()) = Some((Instant::now(), snapshot.clone()));
-    snapshot
-}
-
-fn next_tier_registry_generation() -> u64 {
-    TIER_REGISTRY_GENERATION
-        .fetch_update(Ordering::AcqRel, Ordering::Relaxed, |current| Some(current.saturating_add(1)))
-        .unwrap_or(u64::MAX)
-}
-
-fn validate_tier_registry_names(mut names: Vec<String>) -> Result<Arc<[String]>, ()> {
-    if names.iter().any(|name| {
-        name.is_empty()
-            || name.len() > MAX_TIER_REGISTRY_NAME_BYTES
-            || name.bytes().any(|byte| byte.is_ascii_control())
-            || name == UNKNOWN_TIER
-            || name == storageclass::STANDARD
-            || name == storageclass::RRS
-    }) {
-        return Err(());
-    }
-    names.sort_unstable();
-    if names.windows(2).any(|pair| pair[0] == pair[1]) {
-        return Err(());
-    }
-    Ok(names.into())
-}
+static TIER_NAME_CACHE: RwLock<Option<(Instant, Arc<[String]>)>> = RwLock::new(None);

 /// Tier names currently registered in the tier configuration, cached for
 /// `TIER_NAME_CACHE_TTL`.
 pub(crate) async fn runtime_tier_names() -> Arc<[String]> {
-    runtime_tier_registry().await.names
-}
-
-/// Return the immutable tier registry for one scanner cycle/leader pair.
-/// Different buckets and disks belonging to the same cycle share this entry,
-/// so a TTL refresh cannot split one published cycle across generations.
-pub(crate) async fn runtime_tier_registry_for_cycle(cycle: u64, leader_epoch: u64) -> TierRegistrySnapshot {
-    let key = (cycle, leader_epoch);
-    prune_inactive_tier_cycle_snapshots(cycle, leader_epoch);
    {
-        let cached = TIER_CYCLE_SNAPSHOTS.read().unwrap_or_else(|err| err.into_inner());
-        if let Some(snapshot) = cached.get(&key) {
-            return snapshot.clone();
+        let cached = TIER_NAME_CACHE.read().unwrap_or_else(|err| err.into_inner()).clone();
+        if let Some((refreshed_at, names)) = cached
+            && refreshed_at.elapsed() < TIER_NAME_CACHE_TTL
+        {
+            return names;
        }
    }

-    let mut snapshot = runtime_tier_registry().await;
-    // The registry generation describes the configuration snapshot, not the
-    // scan that consumed it. Keep it stable across cycles so a healthy cache
-    // can be reused; cycle and leader fencing are carried separately by the
-    // cache metadata and scan plan.
-    snapshot.generation = tier_registry_generation(&snapshot.names);
-    let mut cached = TIER_CYCLE_SNAPSHOTS.write().unwrap_or_else(|err| err.into_inner());
-    if let Some(existing) = cached.get(&key) {
-        return existing.clone();
-    }
-    cached.insert(key, snapshot.clone());
-    snapshot
-}
-
-fn prune_inactive_tier_cycle_snapshots(cycle: u64, leader_epoch: u64) {
-    let active = TIER_ACTIVE_CYCLES.read().unwrap_or_else(|err| err.into_inner());
-    let mut snapshots = TIER_CYCLE_SNAPSHOTS.write().unwrap_or_else(|err| err.into_inner());
-    snapshots.retain(|(entry_cycle, entry_epoch), _| {
-        active.contains_key(&(*entry_cycle, *entry_epoch))
-            || *entry_epoch > leader_epoch
-            || (*entry_epoch == leader_epoch && *entry_cycle >= cycle)
-    });
-}
-
-pub(crate) struct TierRegistryCycleGuard {
-    key: (u64, u64),
-}
-
-impl Drop for TierRegistryCycleGuard {
-    fn drop(&mut self) {
-        let mut active = TIER_ACTIVE_CYCLES.write().unwrap_or_else(|err| err.into_inner());
-        if let Some(count) = active.get_mut(&self.key) {
-            *count = count.saturating_sub(1);
-            if *count == 0 {
-                active.remove(&self.key);
-            }
-        }
-    }
-}
-
-pub(crate) fn begin_tier_registry_cycle(cycle: u64, leader_epoch: u64) -> TierRegistryCycleGuard {
-    let mut active = TIER_ACTIVE_CYCLES.write().unwrap_or_else(|err| err.into_inner());
-    let count = active.entry((cycle, leader_epoch)).or_default();
-    *count = count.saturating_add(1);
-    TierRegistryCycleGuard {
-        key: (cycle, leader_epoch),
-    }
-}
-
-fn tier_registry_generation(names: &[String]) -> u64 {
-    let mut hasher = Sha256::new();
-    hasher.update(b"rustfs-tier-registry-v1");
-    for name in names {
-        hasher.update(u64::try_from(name.len()).unwrap_or(u64::MAX).to_le_bytes());
-        hasher.update(name.as_bytes());
-    }
-    let digest = hasher.finalize();
-    let mut prefix = [0_u8; 8];
-    prefix.copy_from_slice(&digest[..8]);
-    u64::from_le_bytes(prefix)
-}
-
-/// Drop cycle snapshots only after the scanner has finished publishing a
-/// cycle. In-flight or retryable cycles must retain their original registry;
-/// TTL/capacity eviction could make a later bucket in the same cycle refresh
-/// to a different generation.
-pub(crate) fn complete_tier_registry_cycle(cycle: u64, leader_epoch: u64) {
-    let active = TIER_ACTIVE_CYCLES.read().unwrap_or_else(|err| err.into_inner());
-    let mut cached = TIER_CYCLE_SNAPSHOTS.write().unwrap_or_else(|err| err.into_inner());
-    cached.retain(|(entry_cycle, entry_epoch), _| {
-        active.contains_key(&(*entry_cycle, *entry_epoch))
-            || *entry_epoch > leader_epoch
-            || (*entry_epoch == leader_epoch && *entry_cycle > cycle)
-    });
+    let tiers = ecstore_get_global_tier_config_mgr().read().await.list_tiers();
+    let names: Arc<[String]> = tiers.iter().map(|tier| tier.name.clone()).collect::<Vec<_>>().into();
+    *TIER_NAME_CACHE.write().unwrap_or_else(|err| err.into_inner()) = Some((Instant::now(), Arc::clone(&names)));
+    names
 }

 /// Test-only cache reset; the production cache has no invalidation hook
@@ -619,9 +408,6 @@ pub(crate) fn complete_tier_registry_cycle(cycle: u64, leader_epoch: u64) {
 #[cfg(test)]
 fn reset_tier_name_cache_for_test() {
    *TIER_NAME_CACHE.write().unwrap_or_else(|err| err.into_inner()) = None;
-    TIER_ACTIVE_CYCLES.write().unwrap_or_else(|err| err.into_inner()).clear();
-    TIER_CYCLE_SNAPSHOTS.write().unwrap_or_else(|err| err.into_inner()).clear();
-    TIER_REGISTRY_GENERATION.store(0, Ordering::Relaxed);
 }

 pub(crate) async fn enqueue_runtime_free_version(oi: ScannerObjectInfo) {
@@ -830,68 +616,6 @@ mod tests {
        assert!(Arc::ptr_eq(&first, &second));
    }

-    #[tokio::test]
-    async fn tier_registry_cycle_snapshot_stays_fixed_while_active() {
-        reset_tier_name_cache_for_test();
-        let cycle = 9_000_001;
-        let leader_epoch = 9_000_002;
-        let guard = begin_tier_registry_cycle(cycle, leader_epoch);
-        let first = runtime_tier_registry_for_cycle(cycle, leader_epoch).await;
-
-        // Simulate a TTL refresh observing a different configuration while the
-        // original cycle is still scanning. The active cycle entry must win.
-        *TIER_NAME_CACHE.write().unwrap_or_else(|err| err.into_inner()) = Some((
-            Instant::now() - TIER_NAME_CACHE_TTL - Duration::from_secs(1),
-            TierRegistrySnapshot {
-                generation: u64::MAX,
-                names: Arc::from(["COLD".to_string()]),
-                refresh_failed: false,
-            },
-        ));
-        let second = runtime_tier_registry_for_cycle(cycle, leader_epoch).await;
-        assert_eq!(second.generation, first.generation);
-        assert_eq!(second.names, first.names);
-
-        drop(guard);
-        complete_tier_registry_cycle(cycle, leader_epoch);
-        reset_tier_name_cache_for_test();
-    }
-
-    #[tokio::test]
-    async fn tier_registry_generation_survives_new_cycle_with_same_names() {
-        reset_tier_name_cache_for_test();
-        let first_cycle = 9_000_011;
-        let second_cycle = first_cycle + 1;
-        let leader_epoch = 9_000_012;
-
-        let first_guard = begin_tier_registry_cycle(first_cycle, leader_epoch);
-        let first = runtime_tier_registry_for_cycle(first_cycle, leader_epoch).await;
-        drop(first_guard);
-        complete_tier_registry_cycle(first_cycle, leader_epoch);
-
-        let second_guard = begin_tier_registry_cycle(second_cycle, leader_epoch);
-        let second = runtime_tier_registry_for_cycle(second_cycle, leader_epoch).await;
-        assert_eq!(first.names, second.names);
-        assert_eq!(first.generation, second.generation);
-
-        drop(second_guard);
-        complete_tier_registry_cycle(second_cycle, leader_epoch);
-        reset_tier_name_cache_for_test();
-    }
-
-    #[test]
-    fn invalid_tier_registry_names_fail_closed_for_refresh() {
-        assert!(validate_tier_registry_names(vec!["COLD\n".to_string()]).is_err());
-        assert!(validate_tier_registry_names(vec![UNKNOWN_TIER.to_string()]).is_err());
-        assert!(validate_tier_registry_names(vec!["COLD".to_string(), "COLD".to_string()]).is_err());
-        assert_eq!(
-            validate_tier_registry_names(vec!["WARM".to_string(), "COLD".to_string()])
-                .expect("valid registry names")
-                .as_ref(),
-            ["COLD".to_string(), "WARM".to_string()]
-        );
-    }
-
    #[test]
    fn foreground_read_guard_tracks_stream_lifetime() {
        reset_foreground_read_activity_for_test();
@@ -16,8 +16,8 @@
 use crate::RUSTFS_META_BUCKET;
 use crate::scanner_budget::{ScannerCycleBudget, ScannerCycleBudgetConfig};
 use crate::scanner_io::{
-    DataUsageCacheReuseOptions, DataUsageCacheScanState, ScannerDiskScanOutcome, ScannerIODisk, acquire_scanner_cache_locks,
-    cache_root_entry_info, current_cache_root_or_prepare_with_generation, scanner_set_disk_inventory,
+    DataUsageCacheScanState, ScannerDiskScanOutcome, ScannerIODisk, acquire_scanner_cache_locks, cache_root_entry_info,
+    current_cache_root_or_prepare, scanner_set_disk_inventory,
 };
 use crate::storage_api::owner::NS_SCANNER_PROTOCOL_VERSION;
 use crate::{
@@ -212,7 +212,6 @@ pub(crate) struct RemoteScannerScanSpec<'a> {
    pub(crate) session_id: Uuid,
    pub(crate) session_sequence: u64,
    pub(crate) scan_plan_digest: DataUsageScanPlanDigest,
-    pub(crate) tier_registry_generation: u64,
    pub(crate) skip_healing: bool,
    pub(crate) scan_mode: HealScanMode,
 }
@@ -223,7 +222,6 @@ struct RemoteScannerResponseExpectation<'a> {
    source: DataUsageCacheSource,
    next_cycle: u64,
    scan_plan_digest: DataUsageScanPlanDigest,
-    tier_registry_generation: u64,
 }

 #[derive(Debug)]
@@ -670,11 +668,6 @@ async fn scan_and_persist_local_bucket(
        scan_mode,
        ..
    } = request;
-    // Keep the worker's cycle snapshot alive through cache reuse, scanning,
-    // and persistence. Without the guard, a later cycle can prune this key
-    // while this request is still running and allow a second registry to be
-    // selected for the same cycle.
-    let _tier_cycle_guard = crate::begin_tier_registry_cycle(next_cycle, leader_epoch);
    let store = resolve_scanner_object_store_handle()
        .ok_or_else(|| RemoteScannerServerError::worker("remote namespace scanner object layer is unavailable"))?;
    validate_remote_scanner_request_fence_with_store(next_cycle, leader_epoch, store.clone())
@@ -707,25 +700,7 @@ async fn scan_and_persist_local_bucket(
    let revisions = cache.load_with_revisions(set.clone(), &cache_name).await.map_err(|err| {
        RemoteScannerServerError::worker(format!("remote namespace scanner cache load or revision lookup failed: {err}"))
    })?;
-    // Remote workers use the same cycle-frozen registry as `scan_data_folder`.
-    // Requiring its generation here prevents a cache snapshot classified by an
-    // older registry from being reused before the folder scan gets a chance to
-    // refresh it.
-    let tier_registry_generation = crate::runtime_tier_registry_for_cycle(next_cycle, leader_epoch)
-        .await
-        .generation;
-    let scan_state = current_cache_root_or_prepare_with_generation(
-        &mut cache,
-        &bucket,
-        source,
-        next_cycle,
-        leader_epoch,
-        scan_plan_digest,
-        DataUsageCacheReuseOptions {
-            require_source: true,
-            tier_registry_generation: Some(tier_registry_generation),
-        },
-    );
+    let scan_state = current_cache_root_or_prepare(&mut cache, &bucket, source, next_cycle, leader_epoch, scan_plan_digest, true);
    match scan_state {
        DataUsageCacheScanState::Current(usage) => {
            if guard.is_lock_lost() {
@@ -869,7 +844,6 @@ pub(crate) async fn scan_remote_bucket(
        session_id,
        session_sequence,
        scan_plan_digest,
-        tier_registry_generation,
        skip_healing,
        scan_mode,
    } = spec;
@@ -958,7 +932,6 @@ pub(crate) async fn scan_remote_bucket(
            source: expected_source,
            next_cycle,
            scan_plan_digest,
-            tier_registry_generation,
        },
        authenticator,
        rpc_deadline,
@@ -1014,7 +987,6 @@ where
            source: expected_source,
            next_cycle: TEST_NEXT_CYCLE,
            scan_plan_digest: expected_scan_plan_digest,
-            tier_registry_generation: 0,
        },
        authenticator,
        Instant::now() + NS_SCANNER_MAX_RPC_LIFETIME,
@@ -1114,11 +1086,6 @@ where
                        "remote namespace scanner returned usage for a different bucket plan",
                    )));
                }
-                if complete.usage.tier_registry_generation != Some(expected.tier_registry_generation) {
-                    return Err(RemoteScannerStreamError::reconciled(StorageError::other(
-                        "remote namespace scanner returned usage for a different tier registry generation",
-                    )));
-                }
                if !complete.usage.entry.children.is_empty() {
                    return Err(RemoteScannerStreamError::reconciled(StorageError::other(
                        "remote namespace scanner returned non-flattened bucket usage",
@@ -195,7 +195,6 @@ fn test_usage(bucket: &str, objects: usize) -> DataUsageEntryInfo {
        name: bucket.to_string(),
        parent: crate::DATA_USAGE_ROOT.to_string(),
        entry,
-        tier_registry_generation: Some(0),
    }
 }

@@ -752,43 +751,6 @@ async fn complete_terminal_frame_reconciles_progress_and_usage() {
    assert_eq!(budget.progress(), (3, 2));
 }

-#[tokio::test]
-async fn terminal_usage_from_a_different_tier_generation_is_rejected() {
-    let request_id = Uuid::new_v4();
-    let writer_auth = FrameAuthenticator::for_test(request_id);
-    let reader_auth = FrameAuthenticator::for_test(request_id);
-    let (mut writer, reader) = tokio::io::duplex(4096);
-    tokio::spawn(async move {
-        let mut usage = test_usage("bucket", 1);
-        usage.tier_registry_generation = Some(1);
-        let mut sequence = 0;
-        write_frame(
-            &mut writer,
-            &writer_auth,
-            &mut sequence,
-            &RemoteScannerFrame::terminal(
-                RemoteScannerProgress::default(),
-                RemoteScannerFrameResult::Complete(Box::new(RemoteScannerComplete {
-                    source: TEST_SOURCE,
-                    scan_plan_digest: TEST_PLAN_DIGEST,
-                    usage,
-                    pending_maintenance_work: false,
-                })),
-            ),
-        )
-        .await
-        .expect("terminal frame should write");
-    });
-
-    let parent = CancellationToken::new();
-    let budget = ScannerCycleBudget::new(&parent, ScannerCycleBudgetConfig::default());
-    let error = consume_remote_scanner_stream(reader, parent, budget, "bucket", TEST_SOURCE, TEST_PLAN_DIGEST, reader_auth)
-        .await
-        .expect_err("generation mismatch must fail closed");
-
-    assert!(error.to_string().contains("tier registry generation"));
-}
-
 #[tokio::test]
 async fn complete_terminal_frame_after_budget_expiry_is_partial() {
    let request_id = Uuid::new_v4();
@@ -55,9 +55,9 @@ use tracing::{debug, error, warn};
 use crate::{
    Disk, DiskError, DiskInfoOptions, Evaluator, Event, LcEventSrc, ListPathRawOptions, ObjectOpts, ReplicationConfig,
    ReplicationHealObject, ReplicationQueueAdmission, ReplicationStatusType, STORAGE_FORMAT_FILE, ScannerDiskExt as _,
-    ScannerLifecycleConfigExt as _, ScannerVersioningConfigExt as _, StorageError, TierRegistrySnapshot, apply_expiry_rule,
-    apply_transition_rule, enqueue_runtime_newer_noncurrent, is_reserved_or_invalid_bucket, list_path_raw, path2_bucket_object,
-    path2_bucket_object_with_base_path, queue_replication_heal, runtime_tier_registry_for_cycle, scanner_is_erasure,
+    ScannerLifecycleConfigExt as _, ScannerVersioningConfigExt as _, StorageError, apply_expiry_rule, apply_transition_rule,
+    enqueue_runtime_newer_noncurrent, is_reserved_or_invalid_bucket, list_path_raw, path2_bucket_object,
+    path2_bucket_object_with_base_path, queue_replication_heal, scanner_is_erasure,
    scanner_replication_config_for_lifecycle_eval,
 };
 use crate::{ScannerObjectInfo as ObjectInfo, ScannerObjectToDelete as ObjectToDelete};
@@ -626,20 +626,6 @@ fn apply_scanner_size_summary(into: &mut DataUsageEntry, summary: &SizeSummary)
    }

    into.add_tier_sizes(&summary.tier_stats);
-    into.add_unknown_tier_stats(&summary.unknown_tier_stats);
-    into.tier_accounting_proof = match (into.tier_accounting_proof, Some(summary.tier_accounting_proof)) {
-        (Some(mut current), Some(next)) => {
-            current.saturating_add(next);
-            Some(current)
-        }
-        (Some(_), None) => None,
-        (None, next) => next,
-    };
-    if into.unknown_tier_stats.as_ref().is_some_and(|stats| stats.counter_overflowed)
-        && let Some(proof) = into.tier_accounting_proof.as_mut()
-    {
-        proof.overflowed = true;
-    }
 }

 fn data_usage_root_has_progress(root: &DataUsageEntry) -> bool {
@@ -650,8 +636,6 @@ fn data_usage_root_has_progress(root: &DataUsageEntry) -> bool {
        || root.delete_markers > 0
        || root.failed_objects > 0
        || root.replication_stats.is_some()
-        || root.all_tier_stats.as_ref().is_some_and(|stats| !stats.is_empty())
-        || root.unknown_tier_stats.as_ref().is_some_and(|stats| !stats.is_empty())
 }

 fn partial_cache_is_useful(root: &DataUsageEntry, pending_heals_changed: bool) -> bool {
@@ -686,9 +670,6 @@ pub struct FolderScanner {
    budget: Arc<ScannerCycleBudget>,
    skip_heal: Arc<std::sync::atomic::AtomicBool>,
    local_disk: Arc<Disk>,
-    /// Tier registry frozen for this folder scan. A refresh applies to the
-    /// next scan and cannot mix generations in one aggregate.
-    tier_registry: TierRegistrySnapshot,
    pending_heals_changed: bool,
    #[cfg(test)]
    list_path_raw_options_observer: Option<mpsc::UnboundedSender<ListPathRawTimeoutSnapshot>>,
@@ -1348,11 +1329,7 @@ impl FolderScanner {
                    continue;
                }

-                let sz = match self
-                    .local_disk
-                    .get_size_with_tier_names(item.clone(), &self.tier_registry.names)
-                    .await
-                {
+                let sz = match self.local_disk.get_size(item.clone()).await {
                    Ok(sz) => sz,
                    Err(e) => {
                        let failure_action = classify_get_size_failure(&item, &e);
@@ -1398,13 +1375,14 @@ impl FolderScanner {
                            // Single-flight (backlog#1894 axis A) — the
                            // recording mode and its guarantees are pinned by
                            // corrupt_metadata_recording below.
-                            let mrf_accepted = rustfs_common::mrf_channel::try_send_mrf_intent(
+                            let mrf_result = rustfs_common::mrf_channel::try_send_mrf_intent_typed(
                                rustfs_common::mrf_channel::MrfKind::MetadataCorruption,
                                &item.bucket,
                                &object,
                                None,
+                                None,
                            );
-                            match corrupt_metadata_recording(mrf_accepted) {
+                            match corrupt_metadata_recording(mrf_result) {
                                CorruptMetadataRecording::LedgerOnly => {
                                    // Recorded as Full (retry-later): admission
                                    // for this target happens in the MRF
@@ -2184,10 +2162,6 @@ pub async fn scan_data_folder(

    let failed_object_ttl = rustfs_utils::get_env_u32(ENV_FAILED_OBJECT_TTL_SECS, DEFAULT_FAILED_OBJECT_TTL_SECS) as u64;
    let failed_objects_max = rustfs_utils::get_env_u32(ENV_FAILED_OBJECTS_MAX, DEFAULT_FAILED_OBJECTS_MAX) as usize;
-    let tier_registry = runtime_tier_registry_for_cycle(cache.info.next_cycle, cache.info.leader_epoch).await;
-    let mut cache = cache;
-    cache.fold_retired_tiers(&tier_registry.names);
-    cache.info.tier_registry_generation = Some(tier_registry.generation);

    // Create folder scanner
    let mut scanner = FolderScanner {
@@ -2216,7 +2190,6 @@ pub async fn scan_data_folder(
        budget: budget.clone(),
        skip_heal,
        local_disk,
-        tier_registry,
        pending_heals_changed: false,
        #[cfg(test)]
        list_path_raw_options_observer: None,
@@ -50,11 +50,12 @@ pub(super) enum CorruptMetadataRecording {
    ImmediateAndLedger,
 }

-pub(super) fn corrupt_metadata_recording(mrf_accepted: bool) -> CorruptMetadataRecording {
-    if mrf_accepted {
-        CorruptMetadataRecording::LedgerOnly
-    } else {
-        CorruptMetadataRecording::ImmediateAndLedger
+pub(super) fn corrupt_metadata_recording(result: rustfs_common::mrf_channel::MrfIngressResult) -> CorruptMetadataRecording {
+    match result {
+        rustfs_common::mrf_channel::MrfIngressResult::Enqueued | rustfs_common::mrf_channel::MrfIngressResult::Coalesced => {
+            CorruptMetadataRecording::LedgerOnly
+        }
+        rustfs_common::mrf_channel::MrfIngressResult::Dropped(_) => CorruptMetadataRecording::ImmediateAndLedger,
    }
 }

@@ -289,62 +290,11 @@ impl ScannerItem {
        item.object_path()
    }

-    fn effective_tier(oi: &ObjectInfo) -> &str {
-        if oi.transitioned_object.status == crate::TRANSITION_COMPLETE {
-            oi.transitioned_object.tier.as_str()
-        } else {
-            oi.storage_class.as_deref().unwrap_or(crate::storageclass::STANDARD)
-        }
-    }
-
-    fn tier_name_is_known(tier: &str, tier_names: &[String]) -> bool {
-        !tier.is_empty()
-            && tier != crate::data_usage_define::UNKNOWN_TIER
-            && (tier == crate::storageclass::STANDARD
-                || tier == crate::storageclass::RRS
-                || tier_names.iter().any(|name| name == tier))
-    }
-
-    pub(crate) fn tier_is_known(oi: &ObjectInfo, tier_names: &[String]) -> bool {
-        Self::tier_name_is_known(Self::effective_tier(oi), tier_names)
-    }
-
-    fn action_requires_known_tier(action: IlmAction) -> bool {
-        matches!(
-            action,
-            IlmAction::TransitionAction
-                | IlmAction::TransitionVersionAction
-                | IlmAction::DeleteAction
-                | IlmAction::DeleteVersionAction
-                | IlmAction::DeleteRestoredAction
-                | IlmAction::DeleteRestoredVersionAction
-                | IlmAction::DeleteAllVersionsAction
-                | IlmAction::DelMarkerDeleteAllVersionsAction
-        )
-    }
-
-    fn action_blocked_by_unknown_tier(
-        action: IlmAction,
-        oi: &ObjectInfo,
-        all_versions_known: bool,
-        tier_names: &[String],
-        target: &str,
-    ) -> bool {
-        if !Self::action_requires_known_tier(action) {
-            return false;
-        }
-        !Self::tier_is_known(oi, tier_names)
-            || (action.delete_all() && !all_versions_known)
-            || (matches!(action, IlmAction::TransitionAction | IlmAction::TransitionVersionAction)
-                && !Self::tier_name_is_known(target, tier_names))
-    }
-
    pub async fn apply_actions(
        &mut self,
        object_infos: Vec<ObjectInfo>,
        lock_retention: Option<Arc<ObjectLockConfiguration>>,
        versioning_config: VersioningConfiguration,
-        tier_names: &[String],
        size_summary: &mut SizeSummary,
    ) {
        let object_path = self.object_path();
@@ -453,9 +403,6 @@ impl ScannerItem {
        let mut noncurrent_accounting: Vec<PendingScannerAccounting<'_>> = Vec::new();
        let mut cumulative_size = 0;
        let mut remaining_versions = object_infos.len();
-        let all_versions_known = object_infos
-            .iter()
-            .all(|candidate| Self::tier_is_known(candidate, tier_names));
        'eventLoop: {
            for (i, event) in events.iter().enumerate() {
                let oi = &object_infos[i];
@@ -479,18 +426,6 @@ impl ScannerItem {
                let mut size = actual_size;
                let mut account_now = true;

-                // A retired/unknown source tier may point at a remote object
-                // that cannot be safely deleted or transitioned. Lifecycle
-                // evaluation is still useful for accounting, but all
-                // side-effecting tier actions fail closed until the registry
-                // recognizes the source again.
-                if Self::action_blocked_by_unknown_tier(event.action, oi, all_versions_known, tier_names, &event.storage_class) {
-                    size = self.heal_actions(oi, actual_size, size_summary).await;
-                    size_summary.actions_accounting(oi, size, actual_size);
-                    cumulative_size += size;
-                    continue;
-                }
-
                match event.action {
                    IlmAction::DeleteAllVersionsAction | IlmAction::DelMarkerDeleteAllVersionsAction => {
                        debug!(
@@ -995,49 +930,4 @@ mod tests {
        assert_eq!(item.object_name, "object");
        assert_eq!(item.object_path(), "object");
    }
-
-    #[test]
-    fn unknown_tier_never_triggers_transition() {
-        let object = ObjectInfo {
-            storage_class: Some("retired-tier".to_string()),
-            ..Default::default()
-        };
-        let tier_names = ["WARM".to_string()];
-        assert!(!ScannerItem::tier_is_known(&object, &tier_names));
-        assert!(ScannerItem::action_requires_known_tier(IlmAction::TransitionAction));
-        assert!(ScannerItem::action_requires_known_tier(IlmAction::DeleteVersionAction));
-        assert!(ScannerItem::action_blocked_by_unknown_tier(
-            IlmAction::TransitionAction,
-            &object,
-            false,
-            &tier_names,
-            "WARM"
-        ));
-        assert!(!ScannerItem::action_blocked_by_unknown_tier(
-            IlmAction::NoneAction,
-            &object,
-            false,
-            &tier_names,
-            "WARM"
-        ));
-
-        let known = ObjectInfo {
-            storage_class: Some(crate::storageclass::STANDARD.to_string()),
-            ..Default::default()
-        };
-        assert!(ScannerItem::action_blocked_by_unknown_tier(
-            IlmAction::DeleteAllVersionsAction,
-            &known,
-            false,
-            &tier_names,
-            "WARM"
-        ));
-        assert!(!ScannerItem::action_blocked_by_unknown_tier(
-            IlmAction::TransitionAction,
-            &known,
-            true,
-            &tier_names,
-            crate::storageclass::STANDARD
-        ));
-    }
 }
@@ -48,8 +48,20 @@ fn scanner_alert_wire_names_match_canonical_event_names() {
 /// the backstop survives regardless of delivery.
 #[test]
 fn corrupt_metadata_recording_maps_delivery_to_backstop() {
-    assert_eq!(corrupt_metadata_recording(true), CorruptMetadataRecording::LedgerOnly);
-    assert_eq!(corrupt_metadata_recording(false), CorruptMetadataRecording::ImmediateAndLedger);
+    assert_eq!(
+        corrupt_metadata_recording(rustfs_common::mrf_channel::MrfIngressResult::Enqueued),
+        CorruptMetadataRecording::LedgerOnly
+    );
+    assert_eq!(
+        corrupt_metadata_recording(rustfs_common::mrf_channel::MrfIngressResult::Coalesced),
+        CorruptMetadataRecording::LedgerOnly
+    );
+    assert_eq!(
+        corrupt_metadata_recording(rustfs_common::mrf_channel::MrfIngressResult::Dropped(
+            rustfs_common::mrf_channel::MrfDropReason::Full
+        )),
+        CorruptMetadataRecording::ImmediateAndLedger
+    );
 }

 fn cooldown_map_len() -> usize {
@@ -325,11 +337,6 @@ async fn build_test_scanner() -> (FolderScanner, std::path::PathBuf) {
        budget: ScannerCycleBudget::new(&CancellationToken::new(), Default::default()),
        skip_heal: Arc::new(AtomicBool::new(false)),
        local_disk: disk,
-        tier_registry: crate::TierRegistrySnapshot {
-            generation: 0,
-            names: Arc::new([]),
-            refresh_failed: false,
-        },
        pending_heals_changed: false,
        list_path_raw_options_observer: None,
    };
@@ -57,9 +57,8 @@ use crate::storage_api::scanner_io::{BucketInfo, BucketOptions};
 use crate::{
    BucketTargetSys, BucketVersioningSys, Disk, DiskError, ECStore, EcstoreError as Error, EcstoreResult as Result,
    RUSTFS_META_BUCKET, ReplicationConfig, STORAGE_FORMAT_FILE, ScannerDiskExt as _, ScannerLifecycleConfigExt as _,
-    ScannerReplicationConfigExt as _, ScannerVersioningConfigExt as _, SetDisks, StorageError, begin_tier_registry_cycle,
-    complete_tier_registry_cycle, enqueue_runtime_free_version, get_lifecycle_config, get_object_lock_config,
-    get_replication_config, runtime_tier_names, runtime_tier_registry_for_cycle, storageclass,
+    ScannerReplicationConfigExt as _, ScannerVersioningConfigExt as _, SetDisks, StorageError, enqueue_runtime_free_version,
+    get_lifecycle_config, get_object_lock_config, get_replication_config, runtime_tier_names, storageclass,
 };

 pub(crate) const SCANNER_SKIP_FILE_ERROR: &str = "skip file";
@@ -144,7 +143,6 @@ pub struct ScannerBucketScanPlan {
    all_buckets: Arc<Vec<BucketInfo>>,
    digest: DataUsageScanPlanDigest,
    leader_epoch: u64,
-    tier_registry_generation: u64,
    dirty_usage_buckets: Arc<DirtyUsageBuckets>,
    bucket_failures: ScannerBucketFailureState,
    pending_maintenance_work: Arc<AtomicBool>,
@@ -343,20 +341,12 @@ pub(crate) fn cache_root_entry_info(cache: &DataUsageCache) -> std::result::Resu
        name: cache.info.name.clone(),
        parent: DATA_USAGE_ROOT.to_string(),
        entry,
-        tier_registry_generation: cache.info.tier_registry_generation,
    })
 }

-fn apply_bucket_result_to_cache(cache: &mut DataUsageCache, result: DataUsageEntryInfo, update_time: SystemTime) -> bool {
-    if cache.info.tier_registry_generation != result.tier_registry_generation {
-        // A result from another registry generation must never be folded into
-        // this cycle. Leaving it unapplied makes the cycle incomplete and
-        // forces the caller to re-account it under one frozen registry.
-        return false;
-    }
+fn apply_bucket_result_to_cache(cache: &mut DataUsageCache, result: DataUsageEntryInfo, update_time: SystemTime) {
    cache.replace(&result.name, &result.parent, result.entry);
    cache.info.last_update = Some(update_time);
-    true
 }

 fn should_publish_completed_snapshot(completed_count: usize, total_count: usize, budget_elapsed: bool, cancelled: bool) -> bool {
@@ -508,9 +498,6 @@ pub trait ScannerIODisk: Send + Sync + Debug + 'static {
    ) -> Result<ScannerDiskScanOutcome>;

    async fn get_size(&self, item: ScannerItem) -> Result<SizeSummary>;
-
-    /// Read one object using a registry snapshot captured at scan start.
-    async fn get_size_with_tier_names(&self, item: ScannerItem, tier_names: &[String]) -> Result<SizeSummary>;
 }

 #[derive(Debug)]
@@ -662,10 +649,7 @@ use cache::*;
 use dirty_usage::*;
 use guards::*;

-pub(crate) use cache::{
-    DataUsageCacheReuseOptions, DataUsageCacheScanState, acquire_scanner_cache_locks,
-    current_cache_root_or_prepare_with_generation,
-};
+pub(crate) use cache::{DataUsageCacheScanState, acquire_scanner_cache_locks, current_cache_root_or_prepare};
 pub use dirty_usage::{
    ScannerDirtyUsageAckError, ScannerDirtyUsageState, acknowledge_dirty_usage_generation, clear_dirty_usage_bucket,
    record_dirty_usage_bucket, record_scanner_maintenance_change, scanner_activity_epoch, scanner_dirty_usage_state,
@@ -100,14 +100,13 @@ where
    let _ = tokio::time::timeout(SCANNER_CACHE_LOCK_LOSS_SHUTDOWN_TIMEOUT, scan).await;
 }

-pub(crate) fn current_cache_root_entry_with_generation(
+pub(crate) fn current_cache_root_entry(
    cache: &DataUsageCache,
    name: &str,
    source: DataUsageCacheSource,
    next_cycle: u64,
    leader_epoch: u64,
    scan_plan_digest: DataUsageScanPlanDigest,
-    tier_registry_generation: Option<u64>,
 ) -> std::result::Result<Option<DataUsageEntryInfo>, ScannerError> {
    let metadata_is_current = cache.info.name == name
        && cache.info.source == Some(source)
@@ -116,8 +115,7 @@ pub(crate) fn current_cache_root_entry_with_generation(
        && cache.info.last_update.is_some()
        && cache.info.next_cycle == next_cycle
        && cache.info.leader_epoch == leader_epoch
-        && cache.info.cache_key_format == DATA_USAGE_CACHE_KEY_FORMAT
-        && tier_registry_generation.is_none_or(|generation| cache.info.tier_registry_generation == Some(generation));
+        && cache.info.cache_key_format == DATA_USAGE_CACHE_KEY_FORMAT;
    if !metadata_is_current {
        return Ok(None);
    }
@@ -133,13 +131,6 @@ pub(crate) enum DataUsageCacheScanState {
    },
 }

-#[derive(Clone, Copy, Debug, Default)]
-pub(crate) struct DataUsageCacheReuseOptions {
-    pub(crate) require_source: bool,
-    pub(crate) tier_registry_generation: Option<u64>,
-}
-
-#[cfg(test)]
 pub(crate) fn current_cache_root_or_prepare(
    cache: &mut DataUsageCache,
    name: &str,
@@ -149,51 +140,11 @@ pub(crate) fn current_cache_root_or_prepare(
    scan_plan_digest: DataUsageScanPlanDigest,
    require_source: bool,
 ) -> DataUsageCacheScanState {
-    current_cache_root_or_prepare_with_generation(
-        cache,
-        name,
-        source,
-        next_cycle,
-        leader_epoch,
-        scan_plan_digest,
-        DataUsageCacheReuseOptions {
-            require_source,
-            tier_registry_generation: None,
-        },
-    )
-}
-
-pub(crate) fn current_cache_root_or_prepare_with_generation(
-    cache: &mut DataUsageCache,
-    name: &str,
-    source: DataUsageCacheSource,
-    next_cycle: u64,
-    leader_epoch: u64,
-    scan_plan_digest: DataUsageScanPlanDigest,
-    options: DataUsageCacheReuseOptions,
-) -> DataUsageCacheScanState {
-    if options.tier_registry_generation.is_some_and(|generation| {
-        cache.info.next_cycle <= next_cycle
-            && cache.info.leader_epoch <= leader_epoch
-            && cache.info.tier_registry_generation != Some(generation)
-    }) {
-        // Make prepare_for_scan take its reset path so an entry classified by
-        // an older registry cannot be reused under the new cycle generation.
-        cache.info.scan_plan_digest = None;
-    }
-    match current_cache_root_entry_with_generation(
-        cache,
-        name,
-        source,
-        next_cycle,
-        leader_epoch,
-        scan_plan_digest,
-        options.tier_registry_generation,
-    ) {
+    match current_cache_root_entry(cache, name, source, next_cycle, leader_epoch, scan_plan_digest) {
        Ok(Some(root)) => DataUsageCacheScanState::Current(Box::new(root)),
        current => DataUsageCacheScanState::Prepared {
            invalid_current: current.err(),
-            outcome: cache.prepare_for_scan(name, next_cycle, leader_epoch, source, scan_plan_digest, options.require_source),
+            outcome: cache.prepare_for_scan(name, next_cycle, leader_epoch, source, scan_plan_digest, require_source),
        },
    }
 }
@@ -208,7 +159,7 @@ pub(super) fn cache_snapshot_is_current(
    scan_plan_digest: DataUsageScanPlanDigest,
 ) -> bool {
    matches!(
-        current_cache_root_entry_with_generation(cache, name, source, next_cycle, leader_epoch, scan_plan_digest, None),
+        current_cache_root_entry(cache, name, source, next_cycle, leader_epoch, scan_plan_digest),
        Ok(Some(_))
    )
 }
@@ -217,7 +168,6 @@ pub(super) fn completed_data_usage_info(
    results: &[DataUsageCache],
    expected_sources: &HashSet<DataUsageCacheSource>,
    all_buckets: &[String],
-    tier_registry_names: &[String],
    bucket_plan_complete: bool,
    budget_elapsed: bool,
    cancelled: bool,
@@ -233,19 +183,6 @@ pub(super) fn completed_data_usage_info(
        return None;
    }

-    // A generation is comparable across nodes because it is derived from the
-    // frozen registry names. Cycle and leader fencing remain separate cache
-    // metadata. Legacy peers omit the generation; an all-legacy result remains
-    // readable, but mixing legacy and new (or two new generations) would make
-    // the per-tier accounting ambiguous.
-    let registry_generation = results.first()?.info.tier_registry_generation;
-    if results.iter().any(|result| match registry_generation {
-        Some(generation) => result.info.tier_registry_generation != Some(generation),
-        None => result.info.tier_registry_generation.is_some(),
-    }) {
-        return None;
-    }
-
    if results.iter().any(|result| result.root().is_none()) {
        return None;
    }
@@ -263,16 +200,9 @@ pub(super) fn completed_data_usage_info(
        if !total.checked_merge(&merged) {
            return None;
        }
-        if !tier_accounting_proof_is_publishable(&merged, registry_generation, tier_registry_names) {
-            return None;
-        }
        buckets_usage.insert(bucket.clone(), checked_bucket_usage_info(&merged)?);
    }

-    if !tier_accounting_proof_is_publishable(&total, registry_generation, tier_registry_names) {
-        return None;
-    }
-
    let merged_last_update = results.iter().filter_map(|result| result.info.last_update).max()?;
    let bucket_sizes = buckets_usage
        .iter()
@@ -286,7 +216,6 @@ pub(super) fn completed_data_usage_info(
        delete_markers_total_count: u64::try_from(total.delete_markers).ok()?,
        objects_total_size: u64::try_from(total.size).ok()?,
        tier_stats: total.all_tier_stats.filter(|tiers| !tiers.is_empty()),
-        unknown_tier_stats: total.unknown_tier_stats.filter(|stats| !stats.is_empty()),
        buckets_count: u64::try_from(all_buckets.len()).ok()?,
        bucket_sizes,
        buckets_usage,
@@ -296,109 +225,6 @@ pub(super) fn completed_data_usage_info(
    Some((data_usage_info, merged_last_update))
 }

-fn tier_accounting_proof_is_publishable(
-    entry: &DataUsageEntry,
-    registry_generation: Option<u64>,
-    tier_registry_names: &[String],
-) -> bool {
-    let has_scalar_usage = entry.size > 0
-        || entry.objects > 0
-        || entry.versions > 0
-        || entry.delete_markers > 0
-        || entry.failed_objects > 0
-        || !entry.obj_sizes.is_empty()
-        || !entry.obj_versions.is_empty()
-        || entry.replication_stats.as_ref().is_some_and(|stats| !stats.is_empty());
-    let has_tier_accounted_data = entry
-        .all_tier_stats
-        .as_ref()
-        .is_some_and(|stats| stats.tiers.values().any(|tier| !tier.is_empty()))
-        || entry.unknown_tier_stats.as_ref().is_some_and(|stats| {
-            stats.counter_overflowed
-                || stats.unknown_bytes > 0
-                || stats.unknown_physical_bytes > 0
-                || stats.unknown_objects > 0
-                || stats.unknown_versions > 0
-        });
-
-    let Some(proof) = entry.tier_accounting_proof else {
-        return !has_scalar_usage && !has_tier_accounted_data;
-    };
-    if proof.overflowed
-        || entry
-            .unknown_tier_stats
-            .as_ref()
-            .is_some_and(|stats| stats.counter_overflowed)
-        || u64::try_from(entry.size).ok() != Some(proof.logical_total)
-    {
-        return false;
-    }
-    let unknown_logical = entry.unknown_tier_stats.as_ref().map_or(0, |stats| stats.unknown_bytes);
-    let unknown_physical = entry
-        .unknown_tier_stats
-        .as_ref()
-        .map_or(0, |stats| stats.unknown_physical_bytes);
-    if proof
-        .logical_known
-        .checked_add(unknown_logical)
-        .is_none_or(|total| total != proof.logical_total)
-        || proof
-            .physical_known
-            .checked_add(unknown_physical)
-            .is_none_or(|total| total != proof.physical_total)
-    {
-        return false;
-    }
-    if registry_generation.is_some()
-        && entry.all_tier_stats.as_ref().is_some_and(|stats| {
-            stats.tiers.keys().any(|tier| {
-                tier != crate::UNKNOWN_TIER
-                    && tier != crate::storageclass::STANDARD
-                    && tier != crate::storageclass::RRS
-                    && !tier_registry_names.iter().any(|allowed| allowed == tier)
-            })
-        })
-    {
-        return false;
-    }
-
-    if !has_tier_accounted_data {
-        return true;
-    }
-
-    let Some(tiers) = entry.all_tier_stats.as_ref() else {
-        return false;
-    };
-    let map_unknown_physical = tiers.tiers.get(crate::UNKNOWN_TIER).map_or(0, |stats| stats.total_size);
-    let companion_unknown_physical = entry
-        .unknown_tier_stats
-        .as_ref()
-        .map_or(0, |stats| stats.unknown_physical_bytes);
-    if map_unknown_physical != companion_unknown_physical {
-        return false;
-    }
-
-    // A no-configuration scan intentionally stores only UNKNOWN_TIER after
-    // the first unknown object; STANDARD/RRS remain absent to preserve the
-    // historical empty-map shape. In that shape the scalar proof is the sole
-    // source of known physical bytes. Configured registries seed at least one
-    // non-UNKNOWN key, whose map total must match the proof.
-    let has_known_tier_map = tiers.tiers.keys().any(|tier| tier.as_str() != crate::UNKNOWN_TIER);
-    if !has_known_tier_map {
-        return true;
-    }
-    let Some(known_tier_physical_total) = tiers
-        .tiers
-        .iter()
-        .filter(|(tier, _)| tier.as_str() != crate::UNKNOWN_TIER)
-        .map(|(_, stats)| stats)
-        .try_fold(0_u64, |total, stats| total.checked_add(stats.total_size))
-    else {
-        return false;
-    };
-    proof.physical_known == known_tier_physical_total
-}
-
 pub(super) async fn send_cache_root_entry_info(
    bucket_result_tx: &mpsc::Sender<DataUsageEntryInfo>,
    cache: &DataUsageCache,
@@ -493,14 +319,13 @@ pub(super) async fn persist_and_publish_cache_snapshot(
        return None;
    }
    if matches!(
-        current_cache_root_entry_with_generation(
+        current_cache_root_entry(
            &persisted,
            DATA_USAGE_ROOT,
            source,
            cache_snapshot.info.next_cycle,
            cache_snapshot.info.leader_epoch,
            scan_plan_digest,
-            cache_snapshot.info.tier_registry_generation,
        ),
        Ok(Some(_))
    ) {
@@ -31,7 +31,6 @@ impl ScannerIOCache for SetDisks {
            all_buckets,
            digest: scan_plan_digest,
            leader_epoch,
-            tier_registry_generation,
            dirty_usage_buckets,
            bucket_failures,
            pending_maintenance_work,
@@ -49,7 +48,6 @@ impl ScannerIOCache for SetDisks {
                    next_cycle: want_cycle,
                    last_update: Some(now),
                    leader_epoch,
-                    tier_registry_generation: Some(tier_registry_generation),
                    source: Some(source),
                    snapshot_complete: true,
                    scan_plan_digest: Some(scan_plan_digest),
@@ -220,13 +218,6 @@ impl ScannerIOCache for SetDisks {
                "Scanner old data usage cache load failed; rebuilding from bucket caches"
            );
        }
-        // Fence a stale set aggregate before copying entries into per-bucket work caches.
-        if old_cache.info.next_cycle <= want_cycle
-            && old_cache.info.leader_epoch <= leader_epoch
-            && old_cache.info.tier_registry_generation != Some(tier_registry_generation)
-        {
-            old_cache.info.scan_plan_digest = None;
-        }
        match old_cache.prepare_for_scan(
            DATA_USAGE_ROOT,
            want_cycle,
@@ -276,7 +267,6 @@ impl ScannerIOCache for SetDisks {
                name: DATA_USAGE_ROOT.to_string(),
                next_cycle: want_cycle,
                leader_epoch,
-                tier_registry_generation: Some(tier_registry_generation),
                source: Some(source),
                snapshot_complete: false,
                scan_plan_digest: Some(scan_plan_digest),
@@ -338,9 +328,8 @@ impl ScannerIOCache for SetDisks {
                        };

                        let mut cache = cache_mutex_clone.lock().await;
-                        if apply_bucket_result_to_cache(&mut cache, result, SystemTime::now()) {
-                            completed_bucket_count_clone.fetch_add(1, Ordering::Relaxed);
-                        }
+                        apply_bucket_result_to_cache(&mut cache, result, SystemTime::now());
+                        completed_bucket_count_clone.fetch_add(1, Ordering::Relaxed);
                    }
                }
            }
@@ -471,7 +460,6 @@ impl ScannerIOCache for SetDisks {
                                session_id: remote_session_id,
                                session_sequence: request_sequence,
                                scan_plan_digest: bucket_scan_plan_digest,
-                                tier_registry_generation,
                                skip_healing: healing,
                                scan_mode,
                            },
@@ -687,17 +675,14 @@ impl ScannerIOCache for SetDisks {
                            continue;
                        }
                    };
-                    let scan_state = current_cache_root_or_prepare_with_generation(
+                    let scan_state = current_cache_root_or_prepare(
                        &mut cache,
                        &bucket.name,
                        source,
                        want_cycle,
                        leader_epoch,
                        bucket_scan_plan_digest,
-                        DataUsageCacheReuseOptions {
-                            require_source: require_cache_source,
-                            tier_registry_generation: Some(tier_registry_generation),
-                        },
+                        require_cache_source,
                    );
                    let outcome = match scan_state {
                        DataUsageCacheScanState::Current(root) => {
@@ -1123,7 +1108,6 @@ impl ScannerIOCache for SetDisks {
                    name: DATA_USAGE_ROOT.to_string(),
                    next_cycle: want_cycle,
                    leader_epoch,
-                    tier_registry_generation: Some(tier_registry_generation),
                    source: Some(source),
                    snapshot_complete: false,
                    scan_plan_digest: Some(scan_plan_digest),
@@ -48,7 +48,6 @@ impl ScannerIOCycle for ECStore {
        scan_mode: HealScanMode,
    ) -> Result<ScannerCycleResult> {
        let child_token = ctx.child_token();
-        let _tier_cycle_guard = begin_tier_registry_cycle(want_cycle, leader_epoch);

        // Check the local pool metadata before listing buckets. A failed or
        // canceled decommission remains suspended after its worker exits, so
@@ -128,8 +127,6 @@ impl ScannerIOCycle for ECStore {
            scanner_bucket_plan_digest(&all_buckets, crate::scanner::scanner_activity_snapshot_digest(&activity_before));
        let dirty_usage_snapshot = Arc::new(snapshot_dirty_usage_buckets(&all_buckets, dirty_generation_before_bucket_list));
        let cache_cycle_floor = Arc::new(AtomicU64::new(want_cycle));
-        let tier_registry = runtime_tier_registry_for_cycle(want_cycle, leader_epoch).await;
-        let tier_registry_generation = tier_registry.generation;

        if all_buckets.is_empty() {
            reset_set_scan_gauges();
@@ -160,9 +157,6 @@ impl ScannerIOCycle for ECStore {
            {
                return Ok(ScannerCycleResult::new(status, None));
            }
-            if status == ScannerCycleStatus::Complete {
-                complete_tier_registry_cycle(want_cycle, leader_epoch);
-            }
            let dirty_usage_clear =
                (status == ScannerCycleStatus::Complete).then(|| dirty_usage_snapshot.buckets.as_ref().clone());
            let remote_dirty_usage_acknowledgements = if status == ScannerCycleStatus::Complete {
@@ -255,7 +249,6 @@ impl ScannerIOCycle for ECStore {
                    all_buckets: Arc::clone(&all_buckets),
                    digest: scan_plan_digest,
                    leader_epoch,
-                    tier_registry_generation,
                    dirty_usage_buckets: dirty_usage_snapshot.buckets.clone(),
                    bucket_failures: bucket_failures.clone(),
                    pending_maintenance_work: pending_maintenance_work.clone(),
@@ -373,7 +366,6 @@ impl ScannerIOCycle for ECStore {
            &results,
            &expected_sources,
            &all_bucket_names,
-            &tier_registry.names,
            bucket_plan_complete,
            budget_elapsed,
            ctx.is_cancelled(),
@@ -399,9 +391,6 @@ impl ScannerIOCycle for ECStore {
            &failed_buckets,
        );
        result?;
-        if cycle_status == ScannerCycleStatus::Complete {
-            complete_tier_registry_cycle(want_cycle, leader_epoch);
-        }
        let remote_dirty_usage_acknowledgements = if cycle_status == ScannerCycleStatus::Complete {
            crate::scanner::scanner_dirty_usage_acknowledgements(&activity_before)
        } else {
@@ -13,38 +13,29 @@
 // limitations under the License.
 /// ScannerIODisk implementation for Disk: get_size and the per-disk bucket scan.
 use super::*;
-use crate::UNKNOWN_TIER;

 ///
 /// Seed [`SizeSummary::tier_stats`] from the cached tier-name list.
 ///
-/// Preserves the original no-tier shape: with no tiers configured the map
-/// stays completely empty (STANDARD/RRS/UNKNOWN are not seeded either).
-/// Otherwise the standard storage classes and one fixed unknown bucket are
-/// seeded alongside every configured tier so per-object accounting never
-/// inserts an untrusted metadata key.
+/// Preserves the original seeding semantics: with no tiers configured the map
+/// stays completely empty (STANDARD/RRS are not seeded either); otherwise the
+/// standard storage classes are seeded alongside every configured tier so
+/// per-object accounting always finds its tier key.
 pub(super) fn tier_stats_template(tier_names: &[String]) -> HashMap<String, TierStats> {
-    let mut tier_stats = HashMap::with_capacity(tier_names.len() + 3);
+    let mut tier_stats = HashMap::with_capacity(tier_names.len() + 2);
    for tier_name in tier_names {
-        if tier_name != UNKNOWN_TIER {
-            tier_stats.insert(tier_name.clone(), TierStats::default());
-        }
+        tier_stats.insert(tier_name.clone(), TierStats::default());
    }
    if !tier_stats.is_empty() {
        tier_stats.insert(storageclass::STANDARD.to_string(), TierStats::default());
        tier_stats.insert(storageclass::RRS.to_string(), TierStats::default());
-        tier_stats.insert(UNKNOWN_TIER.to_string(), TierStats::default());
    }
    tier_stats
 }

 #[async_trait::async_trait]
 impl ScannerIODisk for Disk {
-    async fn get_size(&self, item: ScannerItem) -> Result<SizeSummary> {
-        self.get_size_with_tier_names(item, &runtime_tier_names().await).await
-    }
-
-    async fn get_size_with_tier_names(&self, mut item: ScannerItem, tier_names: &[String]) -> Result<SizeSummary> {
+    async fn get_size(&self, mut item: ScannerItem) -> Result<SizeSummary> {
        let done_object = Metrics::time(Metric::ScanObject);

        if !is_xl_meta_path(&item.path) {
@@ -114,13 +105,12 @@ impl ScannerIODisk for Disk {
            .map(|v| ObjectInfo::from_file_info(v, item.bucket.as_str(), object_path.as_str(), versioned))
            .collect::<Vec<ObjectInfo>>();

-        // The caller supplies one registry snapshot for the whole folder scan;
-        // seeding from it prevents a TTL refresh from mixing generations in a
-        // single result.
-        let mut size_summary = SizeSummary {
-            tier_stats: tier_stats_template(tier_names),
-            ..Default::default()
-        };
+        let mut size_summary = SizeSummary::default();
+
+        // Tier names come from the process-wide TTL cache; seeding from them
+        // replaces the per-object clone of every full TierConfig.
+        let tier_names = runtime_tier_names().await;
+        size_summary.tier_stats = tier_stats_template(&tier_names);

        let lock_config = object_lock_config_for_scanner_item(&item).await;

@@ -130,14 +120,12 @@ impl ScannerIODisk for Disk {
        // `object_infos`.
        global_metrics().record_scanner_versions_scanned(object_infos.len() as u64);

-        item.apply_actions(object_infos, lock_config, versioning_config, tier_names, &mut size_summary)
+        item.apply_actions(object_infos, lock_config, versioning_config, &mut size_summary)
            .await;

        if !free_version_infos.is_empty() {
            for oi in free_version_infos {
-                if ScannerItem::tier_is_known(&oi, tier_names) {
-                    enqueue_runtime_free_version(oi).await;
-                }
+                enqueue_runtime_free_version(oi).await;
            }
        }

@@ -13,8 +13,7 @@
 // limitations under the License.

 use super::*;
-use crate::data_usage_define::{UNKNOWN_TIER, UnknownTierStats, hash_path};
-use rustfs_data_usage::{ReplicationAllStats, ReplicationTargetUsage, TierAccountingProof};
+use rustfs_data_usage::{ReplicationAllStats, ReplicationTargetUsage};

 const TEST_PLAN_DIGEST: DataUsageScanPlanDigest = DataUsageScanPlanDigest([7; 32]);

@@ -90,11 +89,6 @@ fn completed_root_cache(bucket: &str, objects: usize, update_secs: u64, source:
        DataUsageEntry {
            objects,
            size: objects.saturating_mul(10),
-            tier_accounting_proof: Some(TierAccountingProof {
-                logical_total: u64::try_from(objects.saturating_mul(10)).unwrap_or(u64::MAX),
-                logical_known: u64::try_from(objects.saturating_mul(10)).unwrap_or(u64::MAX),
-                ..Default::default()
-            }),
            ..Default::default()
        },
    );
@@ -108,7 +102,7 @@ fn completed_data_usage_info_for_test(
    cancelled: bool,
 ) -> Option<(DataUsageInfo, SystemTime)> {
    let expected_sources = results.iter().filter_map(|result| result.info.source).collect::<HashSet<_>>();
-    completed_data_usage_info(results, &expected_sources, all_buckets, &[], true, budget_elapsed, cancelled)
+    completed_data_usage_info(results, &expected_sources, all_buckets, true, budget_elapsed, cancelled)
 }

 #[test]
@@ -128,21 +122,11 @@ fn completed_data_usage_info_publishes_tier_stats_across_sets() {
    let mut first_set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
    let mut tiered = DataUsageEntry::default();
    tiered.add_tier_sizes(&warm(100, 2, 1));
-    tiered.tier_accounting_proof = Some(TierAccountingProof {
-        physical_total: 100,
-        physical_known: 100,
-        ..Default::default()
-    });
    first_set.replace("bucket-b", DATA_USAGE_ROOT, tiered);

    let mut second_set = completed_root_cache("bucket-b", 2, 20, DataUsageCacheSource::new(1, 0));
    let mut tiered = DataUsageEntry::default();
    tiered.add_tier_sizes(&warm(50, 1, 1));
-    tiered.tier_accounting_proof = Some(TierAccountingProof {
-        physical_total: 50,
-        physical_known: 50,
-        ..Default::default()
-    });
    second_set.replace("bucket-a", DATA_USAGE_ROOT, tiered);

    let (data_usage_info, _) = completed_data_usage_info_for_test(&[first_set, second_set], &all_buckets, false, false)
@@ -161,269 +145,6 @@ fn completed_data_usage_info_publishes_tier_stats_across_sets() {
    );
 }

-#[test]
-fn completed_data_usage_info_rejects_logical_proof_mismatch() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.add_tier_sizes(&HashMap::from([(
-        "WARM".to_string(),
-        TierStats {
-            total_size: 10,
-            num_versions: 1,
-            num_objects: 1,
-        },
-    )]));
-    entry.tier_accounting_proof = Some(TierAccountingProof {
-        logical_total: 10,
-        logical_known: 9,
-        physical_total: 10,
-        physical_known: 10,
-        ..Default::default()
-    });
-
-    assert!(completed_data_usage_info_for_test(&[set], &all_buckets, false, false).is_none());
-}
-
-#[test]
-fn completed_data_usage_info_rejects_logical_total_size_mismatch() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.size = 11;
-    entry.add_tier_sizes(&HashMap::from([(
-        "WARM".to_string(),
-        TierStats {
-            total_size: 10,
-            num_versions: 1,
-            num_objects: 1,
-        },
-    )]));
-    entry.tier_accounting_proof = Some(TierAccountingProof {
-        logical_total: 10,
-        logical_known: 10,
-        physical_total: 10,
-        physical_known: 10,
-        ..Default::default()
-    });
-
-    assert!(completed_data_usage_info_for_test(&[set], &all_buckets, false, false).is_none());
-}
-
-#[test]
-fn completed_data_usage_info_rejects_physical_proof_mismatch() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.add_tier_sizes(&HashMap::from([(
-        "WARM".to_string(),
-        TierStats {
-            total_size: 10,
-            num_versions: 1,
-            num_objects: 1,
-        },
-    )]));
-    entry.tier_accounting_proof = Some(TierAccountingProof {
-        logical_total: 10,
-        logical_known: 10,
-        physical_total: 9,
-        physical_known: 9,
-        ..Default::default()
-    });
-
-    assert!(completed_data_usage_info_for_test(&[set], &all_buckets, false, false).is_none());
-}
-
-#[test]
-fn completed_data_usage_info_rejects_unknown_physical_double_accounting() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.add_tier_sizes(&HashMap::from([(
-        UNKNOWN_TIER.to_string(),
-        TierStats {
-            total_size: 10,
-            num_versions: 1,
-            num_objects: 1,
-        },
-    )]));
-    entry.add_unknown_tier_stats(&UnknownTierStats {
-        unknown_physical_bytes: 9,
-        ..Default::default()
-    });
-    entry.tier_accounting_proof = Some(TierAccountingProof {
-        logical_total: 10,
-        logical_known: 10,
-        physical_total: 10,
-        physical_known: 10,
-        ..Default::default()
-    });
-
-    assert!(completed_data_usage_info_for_test(&[set], &all_buckets, false, false).is_none());
-}
-
-#[test]
-fn completed_data_usage_info_rejects_unknown_counter_overflow() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.add_unknown_tier_stats(&UnknownTierStats {
-        counter_overflowed: true,
-        ..Default::default()
-    });
-
-    assert!(completed_data_usage_info_for_test(&[set], &all_buckets, false, false).is_none());
-}
-
-#[test]
-fn completed_data_usage_info_accepts_no_tier_standard_empty_map_with_proof() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-
-    let (info, _) = completed_data_usage_info_for_test(&[set], &all_buckets, false, false)
-        .expect("no-tier STANDARD/RRS usage does not require a tier map");
-    assert!(info.tier_stats.is_none());
-}
-
-#[test]
-fn completed_data_usage_info_accepts_no_tier_unknown_and_standard_shape() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.size = 13;
-    entry.add_tier_sizes(&HashMap::from([(
-        UNKNOWN_TIER.to_string(),
-        TierStats {
-            total_size: 3,
-            num_versions: 1,
-            num_objects: 1,
-        },
-    )]));
-    entry.add_unknown_tier_stats(&UnknownTierStats {
-        unknown_bytes: 9,
-        unknown_physical_bytes: 3,
-        unknown_objects: 1,
-        unknown_versions: 1,
-        ..Default::default()
-    });
-    entry.tier_accounting_proof = Some(TierAccountingProof {
-        logical_total: 13,
-        logical_known: 4,
-        physical_total: 7,
-        physical_known: 4,
-        ..Default::default()
-    });
-
-    let (info, _) = completed_data_usage_info_for_test(&[set], &all_buckets, false, false)
-        .expect("no-tier STANDARD plus UNKNOWN should remain publishable");
-    assert_eq!(
-        info.tier_stats.expect("unknown bucket should be retained").tiers[UNKNOWN_TIER].total_size,
-        3
-    );
-}
-
-#[test]
-fn completed_data_usage_info_accepts_unknown_only_with_current_registry_generation() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    set.info.tier_registry_generation = Some(7);
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.size = 13;
-    entry.add_tier_sizes(&HashMap::from([(
-        UNKNOWN_TIER.to_string(),
-        TierStats {
-            total_size: 3,
-            num_versions: 1,
-            num_objects: 1,
-        },
-    )]));
-    entry.add_unknown_tier_stats(&UnknownTierStats {
-        unknown_bytes: 9,
-        unknown_physical_bytes: 3,
-        unknown_objects: 1,
-        unknown_versions: 1,
-        ..Default::default()
-    });
-    entry.tier_accounting_proof = Some(TierAccountingProof {
-        logical_total: 13,
-        logical_known: 4,
-        physical_total: 7,
-        physical_known: 4,
-        ..Default::default()
-    });
-
-    let expected_sources = HashSet::from([DataUsageCacheSource::new(0, 0)]);
-    assert!(
-        completed_data_usage_info(&[set], &expected_sources, &all_buckets, &["WARM".to_string()], true, false, false,).is_some()
-    );
-}
-
-#[test]
-fn completed_data_usage_info_rejects_non_registry_tier_in_current_generation() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    set.info.tier_registry_generation = Some(7);
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.add_tier_sizes(&HashMap::from([
-        (
-            "WARM".to_string(),
-            TierStats {
-                total_size: 4,
-                num_versions: 1,
-                num_objects: 1,
-            },
-        ),
-        (
-            "RETIRED".to_string(),
-            TierStats {
-                total_size: 6,
-                num_versions: 1,
-                num_objects: 1,
-            },
-        ),
-    ]));
-    entry.tier_accounting_proof = Some(TierAccountingProof {
-        logical_total: 10,
-        logical_known: 10,
-        physical_total: 10,
-        physical_known: 10,
-        ..Default::default()
-    });
-
-    let expected_sources = HashSet::from([DataUsageCacheSource::new(0, 0)]);
-    assert!(
-        completed_data_usage_info(&[set], &expected_sources, &all_buckets, &["WARM".to_string()], true, false, false,).is_none()
-    );
-}
-
-#[test]
-fn completed_data_usage_info_rejects_legacy_proof_missing_when_tier_accounted() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.add_tier_sizes(&HashMap::from([(
-        "WARM".to_string(),
-        TierStats {
-            total_size: 10,
-            num_versions: 1,
-            num_objects: 1,
-        },
-    )]));
-    entry.tier_accounting_proof = None;
-
-    assert!(completed_data_usage_info_for_test(&[set], &all_buckets, false, false).is_none());
-}
-
-#[test]
-fn completed_data_usage_info_rejects_legacy_proof_missing_for_scalar_usage() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let mut set = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    let entry = set.cache.get_mut(&hash_path("bucket-a").key()).expect("bucket entry");
-    entry.tier_accounting_proof = None;
-
-    assert!(completed_data_usage_info_for_test(&[set], &all_buckets, false, false).is_none());
-}
-
 #[test]
 fn completed_data_usage_info_omits_tier_stats_without_tiered_objects() {
    let all_buckets = vec!["bucket-a".to_string()];
@@ -435,51 +156,6 @@ fn completed_data_usage_info_omits_tier_stats_without_tiered_objects() {
    assert!(data_usage_info.tier_stats.is_none());
 }

-#[test]
-fn completed_data_usage_info_rejects_legacy_and_new_tier_generations_mixed() {
-    let all_buckets = vec!["bucket-a".to_string()];
-    let legacy = completed_root_cache("bucket-a", 1, 10, DataUsageCacheSource::new(0, 0));
-    let mut current = completed_root_cache("bucket-a", 1, 20, DataUsageCacheSource::new(1, 0));
-    current.info.tier_registry_generation = Some(42);
-
-    assert!(
-        completed_data_usage_info_for_test(&[legacy, current], &all_buckets, false, false).is_none(),
-        "legacy and generation-tagged sets must not publish a mixed snapshot"
-    );
-}
-
-#[test]
-fn current_cache_root_with_new_tier_generation_resets_old_cache() {
-    let source = DataUsageCacheSource::new(0, 0);
-    let mut cache = completed_root_cache("bucket-a", 1, 10, source);
-    cache.info.tier_registry_generation = Some(1);
-
-    let state = current_cache_root_or_prepare_with_generation(
-        &mut cache,
-        DATA_USAGE_ROOT,
-        source,
-        0,
-        0,
-        TEST_PLAN_DIGEST,
-        DataUsageCacheReuseOptions {
-            require_source: false,
-            tier_registry_generation: Some(2),
-        },
-    );
-
-    assert!(matches!(
-        state,
-        DataUsageCacheScanState::Prepared {
-            outcome: DataUsageCachePrepareOutcome::Reset,
-            ..
-        }
-    ));
-    assert!(cache.cache.is_empty(), "old-generation entries must not be reused");
-    assert_eq!(cache.info.tier_registry_generation, None);
-    assert_eq!(cache.info.scan_plan_digest, Some(TEST_PLAN_DIGEST));
-    assert!(!cache.info.snapshot_complete);
-}
-
 #[test]
 fn completed_data_usage_info_requires_every_set_before_publish() {
    let all_buckets = vec!["bucket-a".to_string(), "bucket-b".to_string(), "bucket-empty".to_string()];
@@ -604,13 +280,6 @@ fn completed_data_usage_info_flattens_nested_bucket_entries() {
            replica_size: 2048,
            replica_count: 2,
        }),
-        tier_accounting_proof: Some(TierAccountingProof {
-            logical_total: 2048,
-            logical_known: 2048,
-            physical_total: 2048,
-            physical_known: 2048,
-            ..Default::default()
-        }),
        ..Default::default()
    };
    nested.obj_sizes.add(2048);
@@ -678,8 +347,7 @@ fn completed_data_usage_info_requires_exact_topology_sources() {
    let expected_sources = HashSet::from([DataUsageCacheSource::new(0, 0), DataUsageCacheSource::new(1, 0)]);

    assert!(
-        completed_data_usage_info(&[first_set, unexpected_set], &expected_sources, &all_buckets, &[], true, false, false)
-            .is_none()
+        completed_data_usage_info(&[first_set, unexpected_set], &expected_sources, &all_buckets, true, false, false).is_none()
    );
 }

@@ -689,7 +357,7 @@ fn completed_data_usage_info_rejects_incomplete_bucket_plan() {
    let set = completed_root_cache("bucket", 2, 10, DataUsageCacheSource::new(0, 0));
    let expected_sources = HashSet::from([DataUsageCacheSource::new(0, 0)]);

-    assert!(completed_data_usage_info(&[set], &expected_sources, &all_buckets, &[], false, false, false).is_none());
+    assert!(completed_data_usage_info(&[set], &expected_sources, &all_buckets, false, false, false).is_none());
 }

 #[test]
@@ -23,7 +23,7 @@ use crate::storage_api::owner::{
 use crate::storage_api::scan::{BucketOperations as _, DeleteBucketOptions, MakeBucketOptions, ObjectIO as _};
 use crate::{
    DiskOption, ECStore, Endpoint, EndpointServerPools, Endpoints, InstanceContext, PoolEndpoints, ScannerObjectOptions,
-    ScannerPutObjReader, UNKNOWN_TIER, init_bucket_metadata_sys_for_scanner_tests, init_ecstore_config_for_scanner_tests,
+    ScannerPutObjReader, init_bucket_metadata_sys_for_scanner_tests, init_ecstore_config_for_scanner_tests,
    init_local_disks_with_instance_ctx, new_disk, path2_bucket_object_with_base_path,
 };
 use rustfs_filemeta::FileInfo;
@@ -986,8 +986,8 @@ fn is_xl_meta_path_accepts_forward_separator() {
 fn tier_stats_template_seeds_tiers_and_standard_classes() {
    let template = tier_stats_template(&["WARM".to_string(), "COLD".to_string()]);

-    assert_eq!(template.len(), 5);
-    for tier in ["WARM", "COLD", storageclass::STANDARD, storageclass::RRS, UNKNOWN_TIER] {
+    assert_eq!(template.len(), 4);
+    for tier in ["WARM", "COLD", storageclass::STANDARD, storageclass::RRS] {
        assert_eq!(template.get(tier), Some(&TierStats::default()), "missing seed for tier {tier}");
    }
 }
@@ -1328,7 +1328,7 @@ fn apply_bucket_result_to_cache_updates_bucket_entry() {
    );

    let update_time = SystemTime::now();
-    assert!(apply_bucket_result_to_cache(
+    apply_bucket_result_to_cache(
        &mut cache,
        DataUsageEntryInfo {
            name: "bucket".to_string(),
@@ -1338,51 +1338,12 @@ fn apply_bucket_result_to_cache_updates_bucket_entry() {
                objects: 2,
                ..Default::default()
            },
-            tier_registry_generation: None,
        },
        update_time,
-    ));
+    );

    assert_eq!(cache.info.last_update, Some(update_time));
    let entry = cache.find("bucket").expect("bucket entry should remain present");
    assert_eq!(entry.size, 10);
    assert_eq!(entry.objects, 2);
 }
-
-#[test]
-fn apply_bucket_result_to_cache_rejects_a_different_tier_generation() {
-    let mut cache = DataUsageCache {
-        info: DataUsageCacheInfo {
-            name: DATA_USAGE_ROOT.to_string(),
-            tier_registry_generation: Some(7),
-            ..Default::default()
-        },
-        ..Default::default()
-    };
-    cache.replace(
-        "bucket",
-        DATA_USAGE_ROOT,
-        DataUsageEntry {
-            size: 3,
-            ..Default::default()
-        },
-    );
-
-    let applied = apply_bucket_result_to_cache(
-        &mut cache,
-        DataUsageEntryInfo {
-            name: "bucket".to_string(),
-            parent: DATA_USAGE_ROOT.to_string(),
-            entry: DataUsageEntry {
-                size: 11,
-                ..Default::default()
-            },
-            tier_registry_generation: Some(8),
-        },
-        SystemTime::now(),
-    );
-
-    assert!(!applied);
-    assert_eq!(cache.find("bucket").map(|entry| entry.size), Some(3));
-    assert!(cache.info.last_update.is_none());
-}
@@ -46,7 +46,6 @@ pub const NS_SCANNER_SERVER_EPOCH_QUERY: &str = "ns_scanner_server_epoch";
 pub const NS_SCANNER_SESSION_ID_QUERY: &str = "ns_scanner_session_id";
 pub const NS_SCANNER_SESSION_SEQUENCE_QUERY: &str = "ns_scanner_session_sequence";
 pub const NS_SCANNER_PROTOCOL_VERSION_QUERY: &str = "ns_scanner_protocol";
-pub const NS_SCANNER_TIER_REGISTRY_GENERATION_QUERY: &str = "ns_scanner_tier_registry_generation";
 pub const NS_SCANNER_PROTOCOL_VERSION: u16 = 3;
 pub const SCANNER_ACTIVITY_LEGACY_PROTOCOL_VERSION: u32 = 0;
 pub const SCANNER_ACTIVITY_PREVIOUS_PROTOCOL_VERSION: u32 = 5;
@@ -58,8 +57,6 @@ pub struct NsScannerCapabilityResponse {
    pub version: u16,
    pub server_epoch: uuid::Uuid,
    pub proof: Vec<u8>,
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub supports_tier_registry_generation: Option<bool>,
 }

 pub mod admin;
@@ -43,6 +43,9 @@ allow-git = [
    # RustFS fork carrying presigned expiry and constant-time authentication fixes.
    # owner: rustfs-maintainers  review: 2026-10
    "https://github.com/rustfs/s3s.git",
+    # MiMalloc fork pinned for hotpath allocation counting support.
+    # owner: houseme  review: 2026-10
+    "https://github.com/xonatius/mimalloc_rust.git",
 ]

 [bans]
@@ -1,149 +0,0 @@
-# CI gate matrix
-
-This file is the source of truth for which validation runs on each event, its
-configured wall-clock budget, and whether it can block a merge. Test taxonomy,
-naming, and nextest serialization rules remain in [README.md](README.md); e2e
-membership and counts remain in
-[e2e-suite-inventory.md](e2e-suite-inventory.md).
-
-The distinction between **required** and **report-only** is load-bearing:
-a failing job blocks a merge only when its exact check name is present in the
-live `main` ruleset. A workflow name, a `merge_group` trigger, or a red PR check
-does not make a job required by itself.
-
-## Required merge checks
-
-The live `main` ruleset (`6436880`) currently requires exactly these contexts:
-
-| Required context | Producer | Validation |
-|---|---|---|
-| `CLA Check` | `.github/workflows/cla.yml` | Contributor agreement |
-| `Quick Checks` | `.github/workflows/ci.yml` | Formatting and repository guard scripts |
-| `Test and Lint` | `.github/workflows/ci.yml` | Clippy, workspace nextest excluding `e2e_test`, doctests, and migration proofs |
-
-For pull requests limited to the paths excluded by the main CI workflow,
-`.github/workflows/ci-docs-only.yml` reports `Quick Checks` and
-`Test and Lint` under the same names. It runs the real quick checks and the
-planning-document guard; it does not claim that Rust compilation or runtime
-tests ran. Despite the workflow name, these paths also include selected deploy,
-workflow, and lock files.
-
-Verify the live rule rather than trusting this snapshot before changing merge
-policy:
-
-```bash
-gh api repos/rustfs/rustfs/rulesets/6436880 \
-  --jq '.rules[] | select(.type == "required_status_checks") | .parameters'
-```
-
-The ruleset currently has `strict_required_status_checks_policy=false`.
-`Continuous Integration` accepts `merge_group` events and runs `e2e-full` for
-them, but `End-to-End Tests (full merge gate)` is not currently a required
-context. Therefore the repository is prepared to test a merge-queue SHA, but
-the workflow alone does not prove that every merge passed that lane.
-
-## Pull request and merge matrix
-
-Budgets below are job `timeout-minutes`, not typical runtimes. “Report-only”
-means the result is visible and actionable but is not in the live required
-context list.
-
-| Event | Validation | Budget | Merge status | Reproduction |
-|---|---|---:|---|---|
-| PR, non-doc change | `Quick Checks` | 10 min | Required | `make pre-commit` (broader local umbrella) |
-| PR, non-doc change | `Test and Lint` | 90 min | Required | `cargo nextest run --profile ci --all --exclude e2e_test` |
-| PR, non-doc change | `Typos` | 10 min | Report-only | `typos` |
-| PR, non-doc change | `ILM Integration (serial)` | 90 min | Report-only | Use the exact command in `.github/workflows/ci.yml` |
-| PR, non-doc change | rio-v2 / swift / sftp test-and-lint variants | 90 min each | Report-only | `cargo nextest run` with the workflow's feature set |
-| PR, non-doc change | `Build RustFS Debug Binary` | 30 min | Report-only; prerequisite for black-box lanes | `cargo build -p rustfs --bins` |
-| PR, non-doc change | `io_uring Integration (real)` | 30 min | Report-only | `cargo test -p rustfs-ecstore --lib uring_ -- --test-threads=1 --nocapture` |
-| PR, non-doc change | `End-to-End Tests` (`e2e-smoke` plus `s3s-e2e`) | 30 min | Report-only | `cargo nextest run --profile e2e-smoke -p e2e_test`; then `./scripts/e2e-run.sh ./target/debug/rustfs <data-dir>` |
-| PR, non-doc change | `S3 Implemented Tests` | 60 min | Report-only | Build `rustfs`, then run `scripts/s3-tests/run.sh` with `DEPLOY_MODE=binary`, `TEST_MODE=single`, and `MAXFAIL=0` |
-| PR, non-doc change | `S3 Lifecycle Behavior Tests` | 30 min | Report-only | Use the accelerated scanner environment in `.github/workflows/ci.yml` with `scripts/s3-tests/run.sh` |
-| PR touching dependency or workflow inputs | Cargo Deny / Workflow Pin Report / Dependency Review | 20 / 5 / 30 min | Report-only | `cargo deny check`; `scripts/security/check_workflow_pins.sh` |
-| PR touching architecture rules or architecture docs | `Architecture Migration Rules` | 10 min | Report-only | `scripts/check_architecture_migration_rules.sh` |
-| PR touching Nix or workspace manifests | `Nix Build & Check` | 60 min | Report-only | `nix flake check` |
-| PR limited to main-CI-excluded paths | companion `Quick Checks` and `Test and Lint` | 10 min each | Required | `git diff --check`; `make doc-paths-check` when documentation paths changed |
-| `merge_group` | Standard CI plus `e2e-full` | 55 min for `e2e-full` | Standard required contexts only; `e2e-full` report-only | `cargo nextest run --profile e2e-full -p e2e_test` |
-| Push to `main` | Standard CI plus `e2e-full` | 55 min for `e2e-full` | Post-merge detection | Same as `merge_group` |
-| PR touching fuzz inputs or harness paths | Build plus five 60-second fuzz smoke targets | 60 min build; 30 min per target | Report-only | `MAX_TOTAL_TIME=60 ./scripts/fuzz/run.sh` |
-| PR touching selected ecstore disk/format paths | `Rename Safety` on Windows | 60 min | Report-only | Run the four `cargo test -p rustfs-ecstore --lib <filter>` commands in `windows-filesystem.yml` on Windows |
-
-The authoritative e2e filters live in `.config/nextest.toml`; extend a profile
-instead of adding a second ad-hoc selector. Before a profile runs,
-`scripts/check_test_wiring.py` compares its exact membership to the committed
-digest so a silent test drop fails closed.
-
-## Scheduled and manual validation
-
-Scheduled lanes are independent fault domains. They do not block a pull
-request, but their workflow-local gate can fail the run and scheduled failures
-are routed to the shared failure-issue action. The scheduled-validation
-watchdog and freshness workflow separately detect incomplete runs and missing
-schedules.
-
-| Cadence (UTC unless noted) | Workflow / validation | Budget | Verdict and artifacts | Reproduction |
-|---|---|---:|---|---|
-| Daily 02:17 | Fuzz: five nightly corpus targets | 60 min build; 60 min per target | Gate; corpus/crash artifacts, scheduled failure alert | `MAX_TOTAL_TIME=<seconds> ./scripts/fuzz/run.sh` |
-| Daily 03:17 | MinIO interop (EC + SSE read parity) | 40 min | Gate; scheduled failure alert | Dispatch `minio-interop.yml` or follow its pinned Docker fixture steps |
-| Daily 04:29 | Replication / cluster-fault / protocol e2e | 45 / 90 / 90 min | Three independent gates; JUnit, membership, and server logs | `cargo nextest run --profile e2e-repl-nightly -p e2e_test`; `--profile e2e-nightly`; `-j 1 --profile e2e-protocols` |
-| Daily 06:31 | Warp performance A/B | 180 min | Regression budget gate; A/B summaries and server logs | `bash scripts/run_hotpath_warp_abba.sh --help` |
-| Daily 00:07 Asia/Shanghai (16:07 UTC previous day) | Nightly GNU build and Vault lanes | 150 / 90 / 60 min | Build, live Vault, and HA failover gates | Use the commands and pinned Vault images in `nightly-gnu.yml` |
-| Daily 03:23 | Security Audit | 20 / 5 min, plus 30 min on PR dependency review | Cargo Deny and workflow-pin gates; scheduled failure alert | `cargo deny check`; `scripts/security/check_workflow_pins.sh` |
-| Daily 23:47 | Scheduled Validation Freshness | 10 min | Fails when a critical schedule was never created or is stale | Dispatch `scheduled-validation-freshness.yml` |
-| Sunday 00:11 | Full `Continuous Integration` matrix | Per-job budgets above | Weekly variant coverage, including dormant rio-v2 binary/e2e lanes | Dispatch `ci.yml` |
-| Sunday 01:13 | Seven-platform build matrix | 150 min per platform | Build/package integrity; scheduled failure alert | Dispatch `build.yml` with an exact platform set |
-| Sunday 02:19 | Ceph s3-tests full sweep: single and real four-node, four shards each | 180 min per shard | Compatibility gate; report, JUnit, exact node IDs, and server logs | `scripts/s3-tests/run.sh` against an existing single or distributed target |
-| Sunday 06:41 | Mint | 120 min | **Report-only by design**; per-suite PASS/FAIL/NA and raw `log.json` | Reproduce the pinned Docker sequence in `mint.yml` or dispatch it |
-| Sunday 07:43 | Workspace line coverage | 120 min | Report-only trend; lcov and JSON retained 90 days | `make coverage` |
-| Monthly, day 1 06:37 | Runner Hygiene | 15 min | Validates runner ephemerality; scheduled failure alert | Dispatch `runner-hygiene.yml` |
-
-Manual `workflow_dispatch` exists for the scheduled workflows above. Manual
-runs are debugging evidence and intentionally do not open scheduled-failure
-issues. A manual performance run may explicitly allow a known regression; that
-override must not be treated as an ordinary passing baseline.
-
-## Release validation
-
-Release validation is post-merge and tag-driven; it does not substitute for a
-pull-request gate.
-
-| Event | Validation | Budget | Result |
-|---|---|---:|---|
-| Push to `main` or weekly schedule | `Build and Release` platform matrix | 150 min per platform | Build artifacts for all selected targets; no release publication on a main push |
-| Valid release or preview tag | `Build and Release` plus asset checks | 150 min per platform | Draft release, checksummed assets, and publish step |
-| Successful non-preview release-tag build | Docker image build and image scan | 60 min build; 30 min scan | Multi-architecture images plus vulnerability report |
-| Successful release-tag build | DEB/RPM packaging | 30 min per architecture | Packages and checksum files uploaded to the release |
-| Successful non-preview release-tag build | Helm template test and package | 30 min build; 30 min publish | Versioned chart and repository index |
-
-Use an exact preview tag for end-to-end release rehearsal. Manual dispatches
-are backfill/debug paths and do not prove the automatic `workflow_run` chain.
-
-## Evidence requirements
-
-A green check is useful only when it proves the intended behavior ran:
-
- Record the exact commit SHA and run URL.
- Separate product failure from runner prerequisites, service readiness, and
-  cancellation. Repair the precondition, then rerun the exact workload.
- Preserve membership manifests, JUnit, raw compatibility logs, seeds, and
-  server logs where the workflow provides them.
- For a bug fix or a new fault checker, provide sensitivity evidence: the old
-  behavior or an intentional mutation must fail the new oracle, and the fixed
-  behavior must pass it.
- Never promote a report-only lane to required from one green run. Require at
-  least 14 days and 30 representative pull requests with at least 99% complete
-  execution, then update the ruleset and this table together.
-
-## Change checklist
-
-Update this file in the same pull request when any of these change:
-
- workflow triggers, job names, timeouts, or nextest profile ownership;
- required status contexts or strict/merge-queue policy;
- scheduled cadence, alert routing, artifact contract, or local reproduction;
- report-only versus gating semantics.
-
-Do not copy per-module test counts here. Update
-[e2e-suite-inventory.md](e2e-suite-inventory.md) and its enforced membership
-digest instead.
@@ -336,13 +336,13 @@ opentelemetry = { workspace = true }
 tracing-opentelemetry = { workspace = true }
 # Data structures
 hashbrown = { workspace = true, features = ["serde", "rayon"] }
-rustfs-mimalloc = { workspace = true }
+mimalloc = { workspace = true }

 [target.'cfg(target_os = "linux")'.dependencies]
 libsystemd.workspace = true

 [target.'cfg(not(target_os = "windows"))'.dependencies]
-rustfs-mimalloc-sys.workspace = true
+libmimalloc-sys.workspace = true

 [dev-dependencies]
 uuid = { workspace = true, features = ["v4", "v5", "fast-rng", "macro-diagnostics"] }
@@ -369,8 +369,14 @@ pub fn allocator_reclaim_controller_snapshot(ctx: &CancellationToken) -> Allocat
 }

 #[cfg(not(target_os = "windows"))]
+#[allow(unsafe_code)]
 fn collect_allocator_memory(force: bool) -> Result<(), String> {
-    rustfs_mimalloc::MiMalloc::collect(force);
+    // SAFETY: `mi_collect` is provided by the active global allocator backend
+    // on this target family. It is explicitly intended to reclaim retained
+    // pages/segments and does not require additional invariants from the caller.
+    unsafe {
+        libmimalloc_sys::mi_collect(force);
+    }
    Ok(())
 }

@@ -26,22 +26,22 @@ struct MiMallocAllocator;
 unsafe impl GlobalAlloc for MiMallocAllocator {
    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
        // SAFETY: the caller upholds GlobalAlloc's contract for layout.
-        unsafe { rustfs_mimalloc::MiMalloc.alloc(layout) }
+        unsafe { mimalloc::MiMalloc.alloc(layout) }
    }

    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
        // SAFETY: the caller upholds GlobalAlloc's contract for layout.
-        unsafe { rustfs_mimalloc::MiMalloc.alloc_zeroed(layout) }
+        unsafe { mimalloc::MiMalloc.alloc_zeroed(layout) }
    }

    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
        // SAFETY: ptr and layout came from this allocator and are forwarded unchanged.
-        unsafe { rustfs_mimalloc::MiMalloc.dealloc(ptr, layout) }
+        unsafe { mimalloc::MiMalloc.dealloc(ptr, layout) }
    }

    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
        // SAFETY: ptr and layout came from this allocator and are forwarded unchanged.
-        unsafe { rustfs_mimalloc::MiMalloc.realloc(ptr, layout, new_size) }
+        unsafe { mimalloc::MiMalloc.realloc(ptr, layout, new_size) }
    }
 }

@@ -51,7 +51,7 @@ static GLOBAL: hotpath::CountingAllocator<MiMallocAllocator> = hotpath::Counting

 #[cfg(not(all(feature = "hotpath", feature = "hotpath-alloc")))]
 #[global_allocator]
-static GLOBAL: rustfs_mimalloc::MiMalloc = rustfs_mimalloc::MiMalloc;
+static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;

 fn main() {
    let _hotpath_guard = hotpath::HotpathGuardBuilder::new("main").build();
@@ -71,9 +71,8 @@ mod tests {
        allocation.extend_from_slice(&[7_u8; 64]);

        assert_eq!(allocation.len(), 64);
-        let heap = rustfs_mimalloc::heap::Heap::main();
        // SAFETY: the live Vec pointer is valid to inspect for heap ownership.
-        assert!(unsafe { heap.contains(allocation.as_ptr()) });
+        assert!(unsafe { libmimalloc_sys::mi_is_in_heap_region(allocation.as_ptr().cast()) });
    }

    #[test]
@@ -86,13 +85,12 @@ mod tests {
        let layout = Layout::from_size_align(32, 8).expect("valid test allocation layout");
        let grown_layout = Layout::from_size_align(64, 8).expect("valid grown test allocation layout");
        let allocator = super::MiMallocAllocator;
-        let heap = rustfs_mimalloc::heap::Heap::main();

        // SAFETY: The pointer is checked for null before use and later released
        // through the same allocator with the corresponding layout.
        let ptr = unsafe { allocator.alloc_zeroed(layout) };
        assert!(!ptr.is_null());
-        assert!(unsafe { heap.contains(ptr) });
+        assert!(unsafe { libmimalloc_sys::mi_is_in_heap_region(ptr.cast()) });
        assert!(unsafe { std::slice::from_raw_parts(ptr, 32).iter().all(|byte| *byte == 0) });

        // SAFETY: `ptr` was allocated by `allocator` with `layout`; on failure
@@ -104,7 +102,7 @@ mod tests {
            panic!("mimalloc realloc failed in allocator smoke test");
        }

-        assert!(unsafe { heap.contains(grown_ptr) });
+        assert!(unsafe { libmimalloc_sys::mi_is_in_heap_region(grown_ptr.cast()) });
        // SAFETY: `grown_ptr` was reallocated by `allocator` and is released
        // with the matching grown layout.
        unsafe { allocator.dealloc(grown_ptr, grown_layout) };
@@ -17,7 +17,10 @@ use rustfs_io_metrics::{
    record_cpu_usage, record_memory_usage, record_process_memory_split,
 };
 use serde::Serialize;
+#[cfg(any(test, not(target_os = "windows")))]
 use serde_json::Value;
+#[cfg(not(target_os = "windows"))]
+use std::ffi::CStr;
 use std::path::Path;
 use std::sync::{Arc, Mutex, OnceLock};
 use std::time::Duration;
@@ -228,18 +231,7 @@ fn read_cgroup_memory_snapshot() -> Option<CgroupMemorySnapshot> {
    read_cgroup_v2().or_else(read_cgroup_v1)
 }

-fn read_allocator_memory_snapshot() -> Option<AllocatorMemorySnapshot> {
-    let json = rustfs_mimalloc::MiMalloc::stats_json();
-    if json.is_empty() {
-        return None;
-    }
-    let observation = parse_mimalloc_stats_json(&json)?;
-    Some(AllocatorMemorySnapshot {
-        backend: crate::allocator_reclaim::allocator_backend(),
-        observation,
-    })
-}
-
+#[cfg(any(test, not(target_os = "windows")))]
 fn numeric_json_value(value: &Value) -> Option<u64> {
    match value {
        Value::Number(number) => number
@@ -250,6 +242,7 @@ fn numeric_json_value(value: &Value) -> Option<u64> {
    }
 }

+#[cfg(any(test, not(target_os = "windows")))]
 fn numeric_json_field(value: &Value, field: &str) -> Option<u64> {
    match value {
        Value::Object(fields) => fields
@@ -261,6 +254,7 @@ fn numeric_json_field(value: &Value, field: &str) -> Option<u64> {
    }
 }

+#[cfg(any(test, not(target_os = "windows")))]
 fn mimalloc_stat_field(value: &Value, metric: &str, field: &str) -> Option<u64> {
    match value {
        Value::Object(fields) => {
@@ -277,10 +271,12 @@ fn mimalloc_stat_field(value: &Value, metric: &str, field: &str) -> Option<u64>
    }
 }

+#[cfg(any(test, not(target_os = "windows")))]
 fn mimalloc_stat_current(value: &Value, metric: &str) -> Option<u64> {
    mimalloc_stat_field(value, metric, "current")
 }

+#[cfg(any(test, not(target_os = "windows")))]
 fn mimalloc_stat_sum(value: &Value, metrics: &[&str], field: &str) -> Option<u64> {
    metrics
        .iter()
@@ -289,6 +285,7 @@ fn mimalloc_stat_sum(value: &Value, metrics: &[&str], field: &str) -> Option<u64
        .filter(|value| *value > 0)
 }

+#[cfg(any(test, not(target_os = "windows")))]
 fn parse_mimalloc_stats_json(stats_json: &str) -> Option<AllocatorMemoryObservation> {
    let value = serde_json::from_str::<Value>(stats_json).ok()?;
    let malloc_metrics = ["malloc_normal", "malloc_huge"];
@@ -315,6 +312,33 @@ fn parse_mimalloc_stats_json(stats_json: &str) -> Option<AllocatorMemoryObservat
    }
 }

+#[cfg(not(target_os = "windows"))]
+#[allow(unsafe_code)]
+fn read_allocator_memory_snapshot() -> Option<AllocatorMemorySnapshot> {
+    // SAFETY: `mi_stats_get_json` returns a null-terminated JSON buffer owned by
+    // mimalloc when called with a null input buffer. The mimalloc API requires
+    // freeing that buffer with `mi_free`; parsing finishes before the buffer is freed.
+    let observation = unsafe {
+        let stats_ptr = libmimalloc_sys::mi_stats_get_json(0, std::ptr::null_mut());
+        if stats_ptr.is_null() {
+            return None;
+        }
+
+        let observation = CStr::from_ptr(stats_ptr).to_str().ok().and_then(parse_mimalloc_stats_json);
+        libmimalloc_sys::mi_free(stats_ptr.cast());
+        observation?
+    };
+    Some(AllocatorMemorySnapshot {
+        backend: crate::allocator_reclaim::allocator_backend(),
+        observation,
+    })
+}
+
+#[cfg(target_os = "windows")]
+fn read_allocator_memory_snapshot() -> Option<AllocatorMemorySnapshot> {
+    None
+}
+
 fn configured_memory_observability_interval_secs() -> u64 {
    rustfs_utils::get_env_u64(ENV_MEMORY_OBSERVABILITY_INTERVAL_SECS, DEFAULT_MEMORY_OBSERVABILITY_INTERVAL_SECS).max(1)
 }
@@ -542,13 +566,6 @@ mod tests {
        assert_eq!(parse_mimalloc_stats_json(r#"{ "allocator": "unknown" }"#), None);
    }

-    #[test]
-    fn read_allocator_memory_snapshot_uses_mimalloc_stats_json() {
-        let snapshot = super::read_allocator_memory_snapshot();
-        #[cfg(not(target_os = "windows"))]
-        assert!(snapshot.is_some(), "allocator snapshot should be available on non-Windows");
-    }
-
    #[test]
    fn memory_observability_snapshot_reports_disabled_when_metrics_are_disabled() {
        let snapshot = build_memory_observability_status_snapshot(false, 15, false);
@@ -19,15 +19,13 @@ use crate::storage::storage_api::rpc_consumer::http_service::{
    DEFAULT_READ_BUFFER_SIZE, DeleteOptions, DiskStore, NS_SCANNER_PROTOCOL_VERSION, NsScannerCapabilityResponse,
    PUT_FILE_AUTH_TRAILER_LEN, PUT_FILE_AUTH_V1, PUT_FILE_CAPABILITY_VERSION, PutFileCapabilityResponse, StorageDiskRpcExt as _,
    WALK_DIR_STREAM_COMPLETION_V1, WalkDirOptions, check_and_record_signed_rpc_nonce, find_local_disk_by_ref,
-    sign_ns_scanner_capability_with_tier_registry_generation, sign_put_file_capability, verify_put_file_auth_trailer,
-    verify_rpc_signature,
+    sign_ns_scanner_capability, sign_put_file_capability, verify_put_file_auth_trailer, verify_rpc_signature,
 };
 #[cfg(test)]
 use crate::storage::storage_api::rpc_consumer::http_service::{
    NS_SCANNER_BODY_SHA256_QUERY, NS_SCANNER_CAPABILITY_CHALLENGE_QUERY, NS_SCANNER_CYCLE_QUERY, NS_SCANNER_LEADER_EPOCH_QUERY,
    NS_SCANNER_REQUEST_ID_QUERY, NS_SCANNER_SERVER_EPOCH_QUERY, NS_SCANNER_SESSION_ID_QUERY, NS_SCANNER_SESSION_SEQUENCE_QUERY,
-    NS_SCANNER_TIER_REGISTRY_GENERATION_QUERY, PUT_FILE_CAPABILITY_CHALLENGE_QUERY, PUT_FILE_CAPABILITY_QUERY,
-    WALK_DIR_BODY_SHA256_QUERY,
+    PUT_FILE_CAPABILITY_CHALLENGE_QUERY, PUT_FILE_CAPABILITY_QUERY, WALK_DIR_BODY_SHA256_QUERY,
 };
 use crate::storage::storage_api::runtime_sources_consumer::runtime_sources;
 use crate::storage::storage_api::tonic_rpc_auth_failure_reason;
@@ -292,8 +290,6 @@ struct NsScannerQuery {
 struct NsScannerCapabilityQuery {
    ns_scanner_protocol: Option<u16>,
    ns_scanner_challenge: Option<uuid::Uuid>,
-    #[serde(rename = "ns_scanner_tier_registry_generation")]
-    ns_scanner_tier_registry_generation: Option<bool>,
 }

 fn verify_ns_scanner_body_digest(query: &NsScannerQuery, body: &[u8]) -> bool {
@@ -414,9 +410,7 @@ async fn handle_internode_rpc(req: Request<Incoming>) -> Response<Body> {
        (Method::GET, WALK_DIR_PATH) | (Method::HEAD, WALK_DIR_PATH) => handle_walk_dir(req).await,
        (Method::GET, NS_SCANNER_PATH) => match parse_query::<NsScannerCapabilityQuery>(&req) {
            Ok(query) if query.ns_scanner_protocol == Some(NS_SCANNER_PROTOCOL_VERSION) => match query.ns_scanner_challenge {
-                Some(challenge) if !challenge.is_nil() => {
-                    ns_scanner_capability_response(challenge, query.ns_scanner_tier_registry_generation == Some(true))
-                }
+                Some(challenge) if !challenge.is_nil() => ns_scanner_capability_response(challenge),
                Some(_) | None => response_with_status(StatusCode::BAD_REQUEST, "namespace scanner challenge is invalid"),
            },
            Ok(_) => response_with_status(StatusCode::UPGRADE_REQUIRED, "namespace scanner protocol is unsupported"),
@@ -472,34 +466,31 @@ fn record_internode_rpc_error(operation: Option<&'static str>) {
    }
 }

-fn ns_scanner_capability_response(challenge: uuid::Uuid, include_tier_registry_generation: bool) -> Response<Body> {
+fn ns_scanner_capability_response(challenge: uuid::Uuid) -> Response<Body> {
    let server_epoch = *NS_SCANNER_SERVER_EPOCH;
-    let proof =
-        match sign_ns_scanner_capability_with_tier_registry_generation(challenge, server_epoch, include_tier_registry_generation)
-        {
-            Ok(proof) => proof,
-            Err(err) => {
-                error!(
-                    event = EVENT_RPC_REQUEST_FAILED,
-                    component = LOG_COMPONENT_INTERNODE_RPC,
-                    subsystem = LOG_SUBSYSTEM_NAMESPACE_SCANNER,
-                    operation = INTERNODE_OPERATION_NS_SCANNER,
-                    result = "failed",
-                    status_code = StatusCode::UPGRADE_REQUIRED.as_u16(),
-                    rpc_path = NS_SCANNER_PATH,
-                    method = %Method::GET,
-                    reason = "capability_authentication_unavailable",
-                    error = %err,
-                    "internode rpc request failed"
-                );
-                return response_with_status(StatusCode::UPGRADE_REQUIRED, "namespace scanner RPC authentication is unavailable");
-            }
-        };
+    let proof = match sign_ns_scanner_capability(challenge, server_epoch) {
+        Ok(proof) => proof,
+        Err(err) => {
+            error!(
+                event = EVENT_RPC_REQUEST_FAILED,
+                component = LOG_COMPONENT_INTERNODE_RPC,
+                subsystem = LOG_SUBSYSTEM_NAMESPACE_SCANNER,
+                operation = INTERNODE_OPERATION_NS_SCANNER,
+                result = "failed",
+                status_code = StatusCode::UPGRADE_REQUIRED.as_u16(),
+                rpc_path = NS_SCANNER_PATH,
+                method = %Method::GET,
+                reason = "capability_authentication_unavailable",
+                error = %err,
+                "internode rpc request failed"
+            );
+            return response_with_status(StatusCode::UPGRADE_REQUIRED, "namespace scanner RPC authentication is unavailable");
+        }
+    };
    let body = match rmp_serde::to_vec_named(&NsScannerCapabilityResponse {
        version: NS_SCANNER_PROTOCOL_VERSION,
        server_epoch,
        proof,
-        supports_tier_registry_generation: include_tier_registry_generation.then_some(true),
    }) {
        Ok(body) => body,
        Err(err) => {
@@ -1685,13 +1676,12 @@ mod tests {
        LOG_SUBSYSTEM_NAMESPACE_SCANNER, LOG_SUBSYSTEM_ROUTING, NS_SCANNER_BODY_SHA256_QUERY,
        NS_SCANNER_CAPABILITY_CHALLENGE_QUERY, NS_SCANNER_CYCLE_QUERY, NS_SCANNER_LEADER_EPOCH_QUERY, NS_SCANNER_PATH,
        NS_SCANNER_REQUEST_ID_QUERY, NS_SCANNER_SERVER_EPOCH_QUERY, NS_SCANNER_SESSION_ID_QUERY,
-        NS_SCANNER_SESSION_SEQUENCE_QUERY, NS_SCANNER_TIER_REGISTRY_GENERATION_QUERY, NsScannerCapabilityResponse,
-        NsScannerQuery, PUT_FILE_AUTH_STREAM_PATH, PUT_FILE_CAPABILITY_PATH, PUT_FILE_STREAM_PATH, PutFileQuery,
-        READ_FILE_STREAM_PATH, WALK_DIR_BODY_SHA256_QUERY, WALK_DIR_PATH, WalkDirQuery, append_walk_dir_completion,
-        internode_http_operation, internode_rpc_subsystem, is_internode_rpc_path, ns_scanner_response_body,
-        ns_scanner_server_epoch_matches, put_body_size_mismatch, put_file_auth_nonce, put_file_capability_response,
-        put_file_server_epoch_matches, put_file_stage_error_message, put_file_target_lock, read_file_body_stream,
-        read_file_stream_buffer_size, remote_scanner_claim_rejection, response_with_disk_error,
+        NS_SCANNER_SESSION_SEQUENCE_QUERY, NsScannerQuery, PUT_FILE_AUTH_STREAM_PATH, PUT_FILE_CAPABILITY_PATH,
+        PUT_FILE_STREAM_PATH, PutFileQuery, READ_FILE_STREAM_PATH, WALK_DIR_BODY_SHA256_QUERY, WALK_DIR_PATH, WalkDirQuery,
+        append_walk_dir_completion, internode_http_operation, internode_rpc_subsystem, is_internode_rpc_path,
+        ns_scanner_response_body, ns_scanner_server_epoch_matches, put_body_size_mismatch, put_file_auth_nonce,
+        put_file_capability_response, put_file_server_epoch_matches, put_file_stage_error_message, put_file_target_lock,
+        read_file_body_stream, read_file_stream_buffer_size, remote_scanner_claim_rejection, response_with_disk_error,
        supports_walk_dir_stream_completion, validate_walk_dir_completion_request, verify_internode_rpc_signature,
        verify_ns_scanner_body_digest, verify_walk_dir_body_digest, walk_dir_response_body, write_authenticated_put_file,
        write_body_chunks_to_writer, write_put_file_body_chunks_to_writer,
@@ -2124,51 +2114,6 @@ mod tests {
        );
        assert!(serde_urlencoded::from_str::<NsScannerQuery>(&query).is_err());
        assert!(serde_urlencoded::from_str::<super::NsScannerCapabilityQuery>("ns_scanner_protocol=1&unexpected=true").is_err());
-        let marked =
-            format!("ns_scanner_protocol=3&ns_scanner_challenge={request_id}&{NS_SCANNER_TIER_REGISTRY_GENERATION_QUERY}=true");
-        assert_eq!(
-            serde_urlencoded::from_str::<super::NsScannerCapabilityQuery>(&marked)
-                .expect("generation marker should be accepted")
-                .ns_scanner_tier_registry_generation,
-            Some(true)
-        );
-    }
-
-    #[test]
-    fn namespace_scanner_capability_response_support_is_optional_for_old_peers() {
-        #[derive(serde::Deserialize)]
-        #[serde(deny_unknown_fields)]
-        struct LegacyCapabilityResponse {
-            version: u16,
-            server_epoch: uuid::Uuid,
-            proof: Vec<u8>,
-        }
-
-        let old = rmp_serde::to_vec_named(&NsScannerCapabilityResponse {
-            version: super::NS_SCANNER_PROTOCOL_VERSION,
-            server_epoch: uuid::Uuid::new_v4(),
-            proof: vec![1, 2, 3],
-            supports_tier_registry_generation: None,
-        })
-        .expect("old response shape should encode");
-        let decoded: NsScannerCapabilityResponse = rmp_serde::from_slice(&old).expect("old response should decode");
-        assert_eq!(decoded.supports_tier_registry_generation, None);
-        let legacy_decoded: LegacyCapabilityResponse =
-            rmp_serde::from_slice(&old).expect("legacy reader should decode old shape");
-        assert_eq!(legacy_decoded.version, super::NS_SCANNER_PROTOCOL_VERSION);
-        assert!(!legacy_decoded.server_epoch.is_nil());
-        assert_eq!(legacy_decoded.proof, vec![1, 2, 3]);
-
-        let current = rmp_serde::to_vec_named(&NsScannerCapabilityResponse {
-            version: super::NS_SCANNER_PROTOCOL_VERSION,
-            server_epoch: uuid::Uuid::new_v4(),
-            proof: vec![1, 2, 3],
-            supports_tier_registry_generation: Some(true),
-        })
-        .expect("new response shape should encode");
-        let decoded: NsScannerCapabilityResponse = rmp_serde::from_slice(&current).expect("new response should decode");
-        assert_eq!(decoded.supports_tier_registry_generation, Some(true));
-        assert!(rmp_serde::from_slice::<LegacyCapabilityResponse>(&current).is_err());
    }

    #[test]
@@ -224,8 +224,8 @@ pub(crate) mod rpc_consumer {
        pub(crate) use super::super::storage_contracts::{
            NS_SCANNER_BODY_SHA256_QUERY, NS_SCANNER_CAPABILITY_CHALLENGE_QUERY, NS_SCANNER_CYCLE_QUERY,
            NS_SCANNER_LEADER_EPOCH_QUERY, NS_SCANNER_REQUEST_ID_QUERY, NS_SCANNER_SERVER_EPOCH_QUERY,
-            NS_SCANNER_SESSION_ID_QUERY, NS_SCANNER_SESSION_SEQUENCE_QUERY, NS_SCANNER_TIER_REGISTRY_GENERATION_QUERY,
-            PUT_FILE_CAPABILITY_CHALLENGE_QUERY, PUT_FILE_CAPABILITY_QUERY, WALK_DIR_BODY_SHA256_QUERY,
+            NS_SCANNER_SESSION_ID_QUERY, NS_SCANNER_SESSION_SEQUENCE_QUERY, PUT_FILE_CAPABILITY_CHALLENGE_QUERY,
+            PUT_FILE_CAPABILITY_QUERY, WALK_DIR_BODY_SHA256_QUERY,
        };
        pub(crate) use super::super::storage_contracts::{
            NS_SCANNER_PROTOCOL_VERSION, NsScannerCapabilityResponse, PUT_FILE_AUTH_TRAILER_LEN, PUT_FILE_AUTH_V1,
@@ -233,8 +233,8 @@ pub(crate) mod rpc_consumer {
        };
        pub(crate) use super::super::{
            DeleteOptions, DiskStore, StorageDiskRpcExt, WalkDirOptions, check_and_record_signed_rpc_nonce,
-            find_local_disk_by_ref, sign_ns_scanner_capability_with_tier_registry_generation, sign_put_file_capability,
-            verify_put_file_auth_trailer, verify_rpc_signature,
+            find_local_disk_by_ref, sign_ns_scanner_capability, sign_put_file_capability, verify_put_file_auth_trailer,
+            verify_rpc_signature,
        };
    }

@@ -520,10 +520,9 @@ pub(crate) mod ecstore_rpc {
    pub(crate) use rustfs_ecstore::api::rpc::{
        KMS_SIGNAL_SUBSYSTEM, LocalPeerS3Client, PEER_RESTDRY_RUN, PEER_RESTSIGNAL, PEER_RESTSUB_SYS, PeerRestClient,
        PeerS3Client, SERVICE_SIGNAL_REFRESH_CONFIG, SERVICE_SIGNAL_RELOAD_DYNAMIC, TONIC_RPC_PREFIX,
-        check_and_record_signed_rpc_nonce, normalize_tonic_rpc_audience,
-        sign_ns_scanner_capability_with_tier_registry_generation, sign_put_file_capability, sign_tonic_rpc_response_proof,
-        tonic_boot_epoch_challenge, tonic_boot_epoch_response_headers, tonic_rpc_auth_failure_reason,
-        verify_put_file_auth_trailer, verify_rpc_signature, verify_tonic_canonical_body_digest,
+        check_and_record_signed_rpc_nonce, normalize_tonic_rpc_audience, sign_ns_scanner_capability, sign_put_file_capability,
+        sign_tonic_rpc_response_proof, tonic_boot_epoch_challenge, tonic_boot_epoch_response_headers,
+        tonic_rpc_auth_failure_reason, verify_put_file_auth_trailer, verify_rpc_signature, verify_tonic_canonical_body_digest,
        verify_tonic_mutation_body_digest, verify_tonic_rpc_signature_with_bootstrap,
    };
    #[cfg(test)]
@@ -1732,16 +1731,8 @@ pub(crate) fn verify_put_file_auth_trailer(
    ecstore_rpc::verify_put_file_auth_trailer(url, method, nonce, trailer)
 }

-pub(crate) fn sign_ns_scanner_capability_with_tier_registry_generation(
-    challenge: uuid::Uuid,
-    server_epoch: uuid::Uuid,
-    supports_tier_registry_generation: bool,
-) -> std::io::Result<Vec<u8>> {
-    ecstore_rpc::sign_ns_scanner_capability_with_tier_registry_generation(
-        challenge,
-        server_epoch,
-        supports_tier_registry_generation,
-    )
+pub(crate) fn sign_ns_scanner_capability(challenge: uuid::Uuid, server_epoch: uuid::Uuid) -> std::io::Result<Vec<u8>> {
+    ecstore_rpc::sign_ns_scanner_capability(challenge, server_epoch)
 }

 pub(crate) fn sign_put_file_capability(
@@ -241,7 +241,7 @@ env \
  RUSTFS_TEST_VAULT_FAILOVER_MARKER="$MARKER" \
  RUSTFS_TEST_VAULT_OLD_LEADER="$OLD_LEADER" \
  cargo test -p rustfs-kms --test vault_ha_failover_live \
-    vault_raft_leader_failure_recovers_kv2_and_transit_decrypts -- \
+    vault_raft_leader_failure_preserves_kv2_and_transit_decrypts -- \
    --ignored --nocapture --test-threads=1 &
 TEST_PID=$!