rustfs/docs/operations/tier-ilm-debugging.md

Tier / ILM Transition Debugging Guide

How to debug lifecycle tiering (hot → cold transition) issues: inspecting xl.meta, tracing the versionId sent to the remote tier, and known pitfalls.

Code map (post #3929 layout):

Concern	Location
ILM actions (transition_object, expire_transitioned_object, get_transitioned_object_reader, gen_transition_objname)	crates/ecstore/src/bucket/lifecycle/bucket_lifecycle_ops.rs
Erasure-set transition/restore entry points	crates/ecstore/src/set_disk/ and crates/ecstore/src/store/
WarmBackend trait (put/get/remove/in_use)	crates/ecstore/src/services/tier/warm_backend.rs
Per-provider tier backends (S3, MinIO, GCS, Azure, …)	crates/ecstore/src/services/tier/warm_backend_*.rs
Remote-tier sweep (delete_object_from_remote_tier)	crates/ecstore/src/bucket/lifecycle/tier_sweeper.rs
ObjectInfo / TransitionedObject types	crates/ecstore/src/object_api/types.rs
FileMeta / FileInfo / version metadata	crates/filemeta/src/
Dual-key internal metadata helpers (insert_bytes / get_bytes)	crates/utils/src/http/metadata_compat.rs

Metadata key conventions

Internal metadata is stored under both x-rustfs-internal-<suffix> and x-minio-internal-<suffix> for MinIO interoperability. get_bytes prefers the RustFS key and falls back to the MinIO key.

Suffix	Meaning
transition-status	"complete" when tiered
transitioned-object	tier key path (stored without the tier prefix; get_dest adds it)
transitioned-versionID	S3 version_id returned by tier PUT (16 raw UUID bytes, or absent)
transition-tier	tier name
tier-free-versionID	delete-marker version for free-version sweep

Reading binary values must reject empty/malformed/nil values (regression covered in crates/filemeta/src/filemeta/version.rs tests):

get_bytes(&self.meta_sys, SUFFIX_TRANSITIONED_VERSION_ID)
    .and_then(|v| Uuid::from_slice(v.as_slice()).ok())
    .filter(|u| !u.is_nil())
// None for: absent key, wrong-length bytes, nil UUID

transition_version_id == None means the tier bucket is unversioned; the GET/DELETE against the tier must then send no versionId parameter. A nil UUID (00000000-…) sent as ?versionId= causes NoSuchVersion.

Inspect xl.meta directly

cargo build -p rustfs-filemeta --example dump_fileinfo
./target/debug/examples/dump_fileinfo /srv/rustfs/data/disk0/{bucket}/{object}/xl.meta
# Shows: transition_status, transition_tier, transitioned_obj, transition_ver_id

• transition_ver_id: <none> → no versionId will be sent to the tier (correct for a non-versioned tier bucket).
• transition_ver_id: <uuid> → that UUID will be sent as ?versionId=<uuid>.

There is one xl.meta per erasure shard disk ({disk}/{bucket}/{object}/xl.meta); all shards of a healthy object should be identical. dump_versions (same crate) lists every version in a file.

Trace the versionId at runtime

RUST_LOG=rustfs_ecstore::bucket::lifecycle=debug rustfs …

• fetching transitioned object from tier — DEBUG, before the tier request.
• tier GET failed — ERROR, includes tier_version_id.

If both x-rustfs-internal-transitioned-versionID and x-minio-internal-transitioned-versionID are the empty string, the object was transitioned to a non-versioned tier bucket and no versionId must be sent.

Manual transition run

Manual transition run is an operator trigger for the existing lifecycle transition evaluator. It does not force objects that are not due under the bucket lifecycle rule, and it does not bypass versioning, replication, delete-marker, directory-marker, tier, or in-flight transition checks.

The admin endpoint is:

POST /rustfs/admin/v3/ilm/transition/run?bucket=<bucket>&prefix=<prefix>&tier=<tier>&dryRun=true&maxObjects=10000&maxDurationSeconds=30

Only bucket is required. prefix, tier, dryRun, maxObjects, and maxDurationSeconds narrow or bound the run. maxObjects defaults to 10000 and is capped at 100000. maxDurationSeconds is optional, capped at 3600, and enforced as a best-effort budget checked between listed object versions and pages; an in-flight listing call is not cancelled.

The current contract is enqueue_only: the response reports what this bounded scan evaluated and enqueued into the in-memory transition queue. state=completed means the bounded scan reached the end of its current scope without queue pressure or configured budget truncation. It does not mean every remote tier PUT has completed. state=partial means the run stopped early because it hit maxObjects, maxDurationSeconds, or queue pressure (skipped_queue_full, skipped_queue_closed, or skipped_queue_timeout).

job_id and status_endpoint are currently null. There is no durable background job, no restart recovery cursor, no cluster-wide single-flight admission, no status polling endpoint, and no cancel endpoint for this trigger yet. Re-running the command is safe only in the normal lifecycle sense: already in-flight object versions are deduplicated in the local process, but separate nodes do not yet share a durable manual-run admission record.

Recommended operator flow:

rc admin ilm transition run local/mybucket --prefix logs/ --tier cold --dry-run --max-objects 1000 --max-duration-seconds 30
rc admin ilm transition run local/mybucket --prefix logs/ --tier cold --max-objects 1000 --max-duration-seconds 30

Inspect the aggregate counters before widening scope. Full object-key lists are intentionally not returned by the admin response. If RUSTFS_RPC_SECRET or other credentials were pasted into an issue, chat, log, or ticket while debugging tiering, rotate them on every node, restart the cluster with the new value, and redact the exposed copy before sharing more diagnostics.

Historical fixes (for context, already merged)

• Expire/GET race (NoSuchVersion during expiry of a tiered object): expire_transitioned_object used to delete the remote tier version before local metadata, so a concurrent GET between the two steps read a stored version_id whose remote version was already gone. Fixed in #3491: local metadata is deleted first (making the object unreachable), and remote-tier cleanup is driven by persisted free-version recovery (crates/ecstore/src/bucket/lifecycle/tier_free_version_recovery.rs). Invariant — keep local-first ordering: never remove a remote tier version while live local metadata still points at it. Regression test: serial_tests::test_expire_transitioned_object_never_races_concurrent_get in crates/scanner/tests/lifecycle_integration_test.rs (runs in the CI ILM Integration serial lane) pins both the local-first ordering and the "concurrent GET never sees NoSuchVersion" contract.
• Nil-UUID versionId sent to tier (NoSuchVersion): reading code used Uuid::from_slice(..).unwrap_or_default(), converting an empty metadata value into Uuid::nil(). Fixed by the and_then/filter pattern above.
• warm_backend_s3sdk ignored the remote version and range options on GET/DELETE.
• copy_object returned 501 (NotImplemented) for tiered objects on self-copy with --storage-class, blocking de-tiering via mc cp --storage-class STANDARD obj obj. Fixed by writing the tier-fetched put_object_reader back through put_object.