setupReplicaReceiver now reads back canonical addresses from
the ReplicaReceiver (which applies CP13-2 canonicalization)
instead of storing raw assignment addresses in replStates.
This fixes the API-level leak where replica_data_addr showed
":port" instead of "ip:port" in /block/volumes responses,
even though the engine-level CP13-2 fix was working.
New BlockVol.ReplicaReceiverAddr() returns canonical addresses
from the running receiver. Falls back to assignment addresses
if receiver didn't report.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Adds per-replica state reporting in heartbeat so master can identify
which specific replica needs rebuild, not just a volume-level boolean.
New ReplicaShipperStatus{DataAddr, State, FlushedLSN} type reported
via ReplicaShipperStates field on BlockVolumeInfoMessage. Populated
from ShipperGroup.ShipperStates() on each heartbeat. Scales to RF=3+.
V1 constraints (explicit):
- NeedsRebuild cleared only by control-plane reassignment (no local exit)
- Post-rebuild replica re-enters as Disconnected/bootstrap, not InSync
- flushedLSN = checkpointLSN after rebuild (durable baseline only)
4 new tests: heartbeat per-replica state, NeedsRebuild reporting,
rebuild-complete-reenters-InSync (full cycle), epoch mismatch abort.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Flusher now holds WAL entries needed by recoverable replicas.
Both AdvanceTail (physical space) and checkpointLSN (scan gate)
are gated by the minimum flushed LSN across catch-up-eligible
replicas.
New methods on ShipperGroup:
- MinRecoverableFlushedLSN() (uint64, bool): pure read, returns
min flushed LSN across InSync/Degraded/Disconnected/CatchingUp
replicas with known progress. Excludes NeedsRebuild.
- EvaluateRetentionBudgets(timeout): separate mutation step,
escalates replicas that exceed walRetentionTimeout (5m default)
to NeedsRebuild, releasing their WAL hold.
Flusher integration: evaluates budgets then queries floor on each
flush cycle. If floor < maxLSN, holds both checkpoint and tail.
Extent writes proceed normally (reads work), only WAL reclaim
is deferred.
LastContactTime on WALShipper: updated on barrier success,
handshake success, and catch-up completion. Not on Ship (TCP
write only). Avoids misclassifying idle-but-healthy replicas.
CP13-6 ships with timeout budget only. walRetentionMaxBytes
is deferred (documented as partial slice).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Concurrent WriteLBA/Trim calls could deliver WAL entries to replicas
out of LSN order: two goroutines allocate LSN 4 and 5 concurrently,
but LSN 5 could reach the replica first via ShipAll, causing the
replica to reject it as an LSN gap.
shipMu now wraps nextLSN.Add + wal.Append + ShipAll in both
WriteLBA and Trim, guaranteeing LSN-ordered delivery to replicas
under concurrent writers.
The dirty map update and WAL pressure check happen after shipMu
is released — they don't need ordering guarantees.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Adds the sync_all reconnect protocol: when a degraded shipper
reconnects, it performs a handshake (ResumeShipReq/Resp) to
determine the replica's durable progress, then streams missed
WAL entries to close the gap before resuming live shipping.
New wire messages:
- MsgResumeShipReq (0x03): primary sends epoch, headLSN, retainStart
- MsgResumeShipResp (0x04): replica returns status + flushedLSN
- MsgCatchupDone (0x05): marks end of catch-up stream
Decision matrix after handshake:
- R == H: already caught up → InSync
- S <= R+1 <= H: recoverable gap → CatchingUp → stream → InSync
- R+1 < S: gap exceeds retained WAL → NeedsRebuild
- R > H: impossible progress → NeedsRebuild
WALAccess interface: narrow abstraction (RetainedRange + StreamEntries)
avoids coupling shipper to raw WAL internals.
Bootstrap vs reconnect split: fresh shippers (HasFlushedProgress=false)
use CP13-4 bootstrap path. Previously-synced shippers use handshake.
Catch-up retry budget: maxCatchupRetries=3 before NeedsRebuild.
ReplicaReceiver now initializes receivedLSN/flushedLSN from volume's
nextLSN on construction (handles receiver restart on existing volume).
TestBug2_SyncAll_SyncCache_AfterDegradedShipperRecovers flips FAIL→PASS.
All previously-passing baseline tests remain green.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Adds sync.Mutex (superMu) to BlockVol, shared between group commit's
syncWithWALProgress() and flusher's updateSuperblockCheckpoint().
Both paths now serialize superblock mutation + persist, preventing
WALTail/WALCheckpointLSN regression when flusher and group commit
write the full superblock concurrently.
persistSuperblock() also guarded for consistency.
Removes temporary log.Printf lines in the open/recovery path that
were added during BUG-RESTART-ZEROS investigation.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Adds sync.RWMutex (ioMu) to BlockVol enforcing mutual exclusion
between normal I/O and destructive state operations.
Shared (RLock): WriteLBA, ReadLBA, Trim, SyncCache, replica
applyEntry, rebuild applyRebuildEntry — concurrent I/O safe.
Exclusive (Lock): RestoreSnapshot, ImportSnapshot, Expand,
PrepareExpand, CommitExpand, CancelExpand — drains all in-flight
I/O before modifying extent/WAL/dirtyMap.
Scope rule: RLock covers local data-structure mutation only.
Replication shipping is asynchronous and outside the lock, so
exclusive holders block only behind local I/O, not network stalls.
Lock ordering: ioMu > snapMu > assignMu > mu.
Closes the critical ER item: restore/import vs concurrent WriteLBA
silent data corruption gap.
3 new tests: concurrent writes allowed, real restore-vs-write
contention with data integrity check, close coordination.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Preset system: ResolvePolicy resolves named presets (database, general,
throughput) with per-field overrides into concrete volume parameters.
Create path now uses resolved policy instead of ad-hoc validation.
New /block/volume/resolve diagnostic endpoint for dry-run resolution.
Review fix 1 (MED): HasNVMeCapableServer now derives NVMe capability
from server-level heartbeat attribute (block_nvme_addr proto field)
instead of scanning volume entries. Fixes false "no NVMe" warning on
fresh clusters with NVMe-capable servers but no volumes yet.
Review fix 2 (LOW): /block/volume/resolve no longer proxied to leader —
read-only diagnostic endpoint can be served by any master.
Engine fix: ReadLBA retry loop closes stale dirty-map race when WAL
entry is recycled between lookup and read.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Add PressureState() and writer wait tracking to WALAdmission, WALStatus
snapshot API on BlockVol, WAL sizing guidance pure functions, Prometheus
histogram/gauge/counter exports, and admin /status WAL fields. 23 new
tests (7 admission, 10 guidance, 6 QA adversarial).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Two-phase prepare/commit/cancel protocol ensures all replicas expand
atomically. Standalone volumes use direct-commit (unchanged behavior).
Engine: PrepareExpand/CommitExpand/CancelExpand with on-disk
PreparedSize+ExpandEpoch in superblock, crash recovery clears stale
prepare state on open, v.mu serializes concurrent expand operations.
Proto: 3 new RPCs (PrepareExpand/CommitExpand/CancelExpandBlockVolume).
Coordinator: expandClean flag pattern — ReleaseExpandInflight only on
clean success or full cancel. Partial replica commit failure calls
MarkExpandFailed (keeps ExpandInProgress=true, suppresses heartbeat
size updates). ClearExpandFailed for manual reconciliation.
Registry: AcquireExpandInflight records PendingExpandSize+ExpandEpoch.
ExpandFailed state blocks new expands until cleared.
Tests: 15 engine + 4 VS + 10 coordinator + heartbeat suppression
regression + updated QA CP82/durability tests with prepare/commit mocks.
Also includes CP11A-1 remaining: QA storage profile tests, QA
io_backend config tests, testrunner perf-baseline scenarios and
coordinated-expand actions.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add counters (total, soft, hard, timeout) and wait-time histogram to
WALAdmission, wired through EngineMetrics and exported as Prometheus
metrics. Six new tests verify all code paths. Nil-safe for backwards
compatibility.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
All three io_uring backends (iceber, giouring, raw) now require explicit
build tags — no tag means standard-only. Each backend registers its name
via IOUringImpl so startup logs show compiled implementation alongside
requested/selected backend mode.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace UseIOUring bool with IOBackend IOBackendMode (tri-state):
- "standard" (default): sequential pread/pwrite/fdatasync
- "auto": try io_uring, fall back to standard with warning log
- "io_uring": require io_uring, fail startup if unavailable
NewIOUring now returns ErrIOUringUnavailable instead of silently
falling back — callers decide whether to fail or fall back based
on the requested mode. All mode transitions are logged:
io backend: requested=auto selected=standard reason=...
io backend: requested=io_uring selected=io_uring
CLI: --io-backend=standard|auto|io_uring added to iscsi-target.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
1. HIGH: LinkedWriteFsync now uses SubmitLinkRequests (IOSQE_IO_LINK)
instead of SubmitRequests, ensuring write+fdatasync execute as a
linked chain in the kernel. Falls back to sequential on error.
2. HIGH: PreadBatch/PwriteBatch chunk ops by ring capacity to prevent
"too many requests" rejection when dirty map exceeds ring size (256).
3. MED: CloseBatchIO() added to Flusher, called in BlockVol.Close()
after final flush to release io_uring ring / kernel resources.
4. MED: Sync parity — both standard and io_uring paths now use
fdatasync (via platform-specific fdatasync_linux.go / fdatasync_other.go).
Standard path previously used fsync; now matches io_uring semantics.
On non-Linux, fdatasync falls back to fsync (only option available).
10 batchio tests, all blockvol tests pass.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add iouring_linux.go (build-tagged linux && !no_iouring) using
iceber/iouring-go for batched pread/pwrite/fdatasync. Includes
linked write+fsync chain for group commit optimization.
iouring_other.go provides silent fallback to standard on non-Linux.
blockvol.go wires UseIOUring config flag through to flusher BatchIO.
NewIOUring gracefully falls back if kernel lacks io_uring support.
10 batchio tests, all blockvol tests pass unchanged.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Sparse delta-file snapshots with copy-on-write in the flusher.
Zero write-path overhead when no snapshot is active.
New: snapshot.go (SnapshotBitmap, SnapshotHeader, delta file I/O)
Modified: flusher.go (flushMu, CoW phase in FlushOnce, PauseAndFlush)
Modified: blockvol.go (Create/Read/Delete/Restore/ListSnapshots, recovery)
Modified: wal_writer.go (Reset for snapshot restore)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add ALUA (Asymmetric Logical Unit Access) support to the iSCSI target,
enabling dm-multipath on Linux to automatically detect path state changes
and reroute I/O during HA failover without initiator-side intervention.
- ALUAProvider interface with implicit ALUA (TPGS=0x01)
- INQUIRY byte 5 TPGS bits, VPD 0x83 with NAA+TPG+RTP descriptors
- REPORT TARGET PORT GROUPS handler (MAINTENANCE IN SA=0x0A)
- MAINTENANCE OUT rejection (implicit-only, no SET TPG)
- Standby write rejection (NOT_READY ASC=04h ASCQ=0Bh)
- RoleNone maps to Active/Optimized (standalone single-node compatibility)
- NAA-6 device identifier derived from volume UUID
- -tpg-id flag with [1,65535] validation
- dm-multipath config + setup script (group_by_tpg, ALUA prio)
- 12 unit tests + 16 QA adversarial tests + 4 integration tests
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add SimulatedMaster test helper + 20 assignment sequence tests (8 sequence,
5 failover, 5 adversarial, 2 status). Add BlockVolumeStatus struct and
Status() method. Includes QA test files for CP1-CP4a. 940 total unit tests.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add master-driven lifecycle operations: promotion, demotion, rebuild,
and split-brain prevention. All testable on Windows with mock TCP.
New files:
- promotion.go: HandleAssignment (single entry point for role changes),
promote (Replica/None -> Primary with durable epoch), demote
(Primary -> Draining -> Stale with drain timeout)
- rebuild.go: RebuildServer (WAL catch-up + full extent streaming),
StartRebuild client (WAL catch-up with full extent fallback,
two-phase rebuild with second catch-up for concurrent writes)
Modified:
- wal_writer.go: ScanFrom() method, ErrWALRecycled sentinel
- repl_proto.go: rebuild message types + RebuildRequest encode/decode
- blockvol.go: assignMu, drainTimeout, rebuildServer fields;
HandleAssignment/StartRebuildServer/StopRebuildServer methods;
rebuild server stop in Close()
- dirty_map.go: Clear() method for full extent rebuild
32 new tests covering WAL scan, promotion/demotion, rebuild server,
rebuild client, split-brain prevention, and full lifecycle scenarios.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Primary ships WAL entries to replica over TCP (data channel), confirms
durability via barrier RPC (control channel). SyncCache runs local fsync
and replica barrier in parallel via MakeDistributedSync. When replica is
unreachable, shipper enters permanent degraded mode and falls back to
local-only sync (Phase 3 behavior).
Key design: two separate TCP ports (data+control), contiguous LSN
enforcement, epoch equality check, WAL-full retry on replica,
cond.Wait-based barrier with configurable timeout, BarrierFsyncFailed
status code. Close lifecycle: shipper → receiver → drain → committer →
flusher → fd.
New files: repl_proto.go, wal_shipper.go, replica_apply.go,
replica_barrier.go, dist_group_commit.go
Modified: blockvol.go, blockvol_test.go
27 dev tests + 21 QA tests = 48 new tests; 889 total (609 engine + 280
iSCSI), all passing.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
