* volume.fix.replication: add a well-placed replica before deleting a misplaced one
A misplaced volume with no surplus replica (replica count == copy count) used to have its misplaced replica deleted first, and the replacement copied only on the next pass. That drops the volume below its intended durability, and permanently so when no destination can accept the replacement copy. Now such volumes get a well-placed replica first, and the misplaced one is trimmed as surplus on a later pass, following the same fulfill-before-delete principle as volume.tier.move (#8950).
The classification switch is extracted into classifyReplicaSet so the add-wins-over-trim priority is unit-testable.
Also stop the fix loop when an -apply pass makes no progress (nothing copied, nothing deleted); previously an unplaceable under-replicated volume made the loop spin forever, re-collecting the topology every 15 seconds. And propagate ewg.Wait() errors instead of swallowing them.
* volume.fix.replication: drop unused allLocations from deleteOneVolume
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Co-authored-by: Chris Lu <chris.lu@gmail.com>
* volume: verify before destroy in VolumeCopy and replication repair
Four data-safety fixes around copy/repair paths that could destroy or
resurrect data before verifying the source or survivors.
(a) VolumeCopy no longer deletes a pre-existing local replica up front.
The delete is deferred until ReadVolumeFileStatus on the source succeeds,
so a transient source outage (or a retry after one) can no longer wipe a
healthy destination replica. Gated on source readability only; size/count
comparisons are intentionally not used because they invert legitimately
after divergent vacuum/compaction. Mirrored in the Rust volume server.
(b) volume.check.disk no longer resurrects vacuumed-deleted needles. A
key present-and-live on the source but entirely absent on the target is
ambiguous: it may be a genuine missing write, or a needle deleted on the
target and then vacuumed (its index entry and any tombstone are gone). An
individual needle AppendAtNs has no monotonic relation to a vacuum
watermark, so the old cutoff heuristic could not tell them apart. Without
positive proof the absence is a missing write, the safe default is to NOT
push it back. Tradeoff: a real missing write may go unrepaired until a
tombstone-aware path exists, but we never raise back deleted data.
(c) Over-replication trim no longer resurrects needles or removes the
wrong replica. The pre-delete sync now runs read-only (divergence check
only) instead of writing the doomed replica's needles into the survivor.
pickOneReplicaToDelete only ever removes the smallest of multiple healthy
writable replicas; it refuses the trim when doing so would leave only
read-only/integrity-flagged survivors, since file_count>0 alone cannot
prove the survivor's .dat is readable.
(d) Incomplete-volume (.note) cleanup keeps the shared .vif when an .ecx
for the same vid coexists on the disk, so removing an interrupted regular
copy cannot strip a coexisting EC volume's info file. VolumeCopy now
surfaces .note write/remove errors instead of ignoring them. In the Rust
volume server (where a persisting note is actually reachable) the .note
check moves below the empty-stub sweep and EC validation, keeps the .vif
on EC coexistence, and the mount path fails when a .note still persists.
* shell: scope the over-replication writable-survivor guard to the trim path only
The writable-survivor guard (never trim down to a read-only survivor) lived
inside the shared pickOneReplicaToDelete, so it also gated the misplaced-volume
relocation via pickOneMisplacedVolume -- a misplaced read-only volume (e.g. a
full one) would silently stop being rebalanced. Extract pickSmallestReplica
for the relocation path (which deletes-and-recreates and must act on read-only
replicas), and keep the writable-survivor guard only in pickOneReplicaToDelete
used by the over-replication trim.
* seaweed-volume: recompute keep_vif after invalid-EC cleanup in the .note path
keep_vif used the pre-validation ecx_exists snapshot, so when the EC-validation
step above removed the invalid .ecx/shards, the .note cleanup still preserved a
now-orphaned .vif. Re-check .ecx existence at cleanup time, matching the Go
hasEcxFile re-check.
* shell: keep placement when picking an over-replication victim to delete
The trim picked the smallest writable replica without regard to placement, so
it could delete the only replica in a required failure domain (e.g. with "100"
and replicas dc1 + two in dc2, deleting dc1 leaves both survivors in dc2).
Prefer a writable replica whose removal still satisfies placement, falling back
to the smallest writable only when none does.
Chris LuandGitHub
Max DenushevandGitHub
zehwehandChris Lu
chrislu