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rustfs/docs
Chris An d88f524d9f fix(ecstore): serve the latest readable version past dangling versions (#9004)
* fix(ecstore): select the latest version at read quorum like MinIO

GET and HEAD escalated latest-version selection to write quorum when
enough metadata answered and skipped a newer version below write quorum
on degraded reads. LIST and heal already pick the newer side of a split
write at read quorum, so such keys listed but answered 503 until heal.

Select with MinIO's getObjectFileInfo rule: the most common mod time
that reaches the object's data blocks wins, ties go to the newer time,
and one content identity at that time must reach the same quorum. Two
identities tied at the selected time fail instead of resolving by hash
order, and the selected identity's version-stack shape follows disk
order.

* fix(ecstore): resolve selection ties by disk order and guard writes

Review of the read-quorum selection found three gaps:

- Rejecting a same-time half split made explicit-version reads of a
  partially applied tagging update fail and blocked the retry that
  repairs it. Resolve ties to the identity on the lowest-index disk,
  for reads and heal alike, instead of rejecting or using map order.
- Delete markers and empty versions can lower the common read quorum
  below the selected version's data blocks, so HEAD could report a
  version GET cannot decode. Require that many copies, as MinIO's
  getLatestFileInfo does.
- A selection can now return exactly read-quorum disks, and partial
  metadata writes are not rolled back. Refuse an update before writing
  when its target disks cannot reach write quorum.

* fix(ecstore): count identity copies in the data-blocks guard

The first-candidate shortcut counts byte-identical copies, so copies
that differ only in identity-neutral fields such as replication status
were missing from the data-blocks check. When the shortcut's count
falls short, count every copy of the selected content identity before
refusing the version.

* fix(ecstore): keep commit-proof selection for system-bucket reads

Pool metadata's PREPARE/COMMIT recovery and identity epochs treat an
ordinary read of pool.bin as proof that the record committed. Under the
read-quorum rule, a COMMIT that reached only half of a 2+2 set was served
as committed, and the pool_meta_native_physical_* integration tests
failed.

Route reads through select_fileinfo_for_read: S3 buckets keep MinIO's
read-quorum rule, while is_meta_bucketname reads use the previous
algorithm unchanged as select_committed_fileinfo, so a split stays
unreadable until native recovery resolves it.

* fix(ecstore): serve the latest readable version past dangling versions

A failed versioned PUT whose rollback also failed can leave the new
version on top of fewer drives than its data blocks. Reading only each
drive's top version then left the committed version below it short of
read quorum, so GET and HEAD of the latest version answered 503 although
that version is intact in every stack. MinIO resolves the stacks in
pickLatestQuorumFilesInfo.

When every drive answered and an S3 latest read still cannot select a
version, walk the newest version headers of each stack through
exact-version reads: serve the readable version with the newest selected
modification time, skip versions whose exact read proves them dangling
(the NoSuchVersion an explicit GET reports) and queue heal for them, and
keep the read-quorum error on any other outcome. Candidates are ordered
by each version's newest modification time across drives, and at most
eight exact reads are spent.

Test PUTs now wait for every drive so tests that edit one drive's
metadata no longer race the PUT's background tail writes.

* chore(ci): shrink the error(format!) ratchet baseline for rebalance

The rebalance control and meta modules now have fewer
Error::other(format!) call sites than the baseline records, which
fails the shrink-only ratchet in Quick Checks. Record the smaller
counts.

* fix(ecstore): preserve canonical order in latest-version fallback
2026-10-28 06:16:19 +08:00
..

Documentation

Use the focused indexes rather than treating this directory as an unordered collection:

Operations

For PUT cleanup admission, blocking-pool isolation, and optional CPU affinity, see PUT cleanup isolation.

For the logical per-operation io_uring read cap, see io_uring read chunk size.

For bounded local read-backend startup and cancellation, see io_uring backend initialization.

For legacy protection assessment and bounded protected copies, see Object integrity inventory, audit, and migration.

For encrypted listing compatibility and older stored fingerprints, see Encrypted object ETags.

For durable hard quota accounting, node-outage behavior, and fence protocol upgrades, see Durable hard quotas.

Operational runbooks live under operations/. Replication operators should start with:

Runbook Use it for
Site replication operations Health fields, pending operations, outage recovery, re-pair admission, IAM/SSE boundaries, and upgrades.
Replication target check Validating an S3 destination and version fidelity before enabling replication.
Replication object size limits Multipart routing, large-object limits, and retry characteristics.
Replication outbound transport Integrity headers, generic target behavior, and transport knobs.

For the erasure-coded cluster lifecycle (planning, parity and EC:0, expansion, rebalance, decommission, heal, drive replacement, restart recovery, and the rc CLI mapping), start with Cluster and erasure-coding lifecycle operations.

For concurrent bucket creation and deletion, see Bucket operation admission.

For persisted administrator bucket tasks and bucket recreation, see Bucket heal recovery.

For interrupted object deletions and returning drives, see Delete transaction recovery.

For disk replacement across VM restarts and schema 5/6 maintenance migration, see Replacement generation recovery.

For historical GET timeouts during PUT or Heal, see Object lock contention diagnostics.

Other runbooks remain grouped by filename in operations/; architecture pages link to the relevant runbook where a cross-boundary procedure is required.

For storage dashboards, see Storage metrics and observer selection: drive ownership, snapshot freshness, counter queries, and rolling upgrades.

For per-bucket capacity and object counts, see Bucket usage metrics: OTLP export, cluster deduplication, accounting semantics, and scanner freshness.

For optional shard commitments, see Independent shard integrity rollout: activation, legacy repair results, multipart mode changes, and rollback limits.

For crates.io publication of workspace crates, see Workspace Cargo Publish: dependency ordering, dry-run, publish, and failure handling.