Files
seaweedfs/weed/storage/blockvol/test/component
pingqiuandClaude Opus 4.6 ebe95b6e2e fix: flusher OOM on multi-block writes + testrunner enhancements
Bug: flusher.go:336 allocated make([]byte, entryLen) per dirty block
instead of per unique WAL entry. A 4MB WriteLBA creates 1024 dirty map
entries (one per 4KB block), all sharing the same WAL offset. The flusher
read the full 4MB WAL entry 1024 times into separate buffers:
1024 × 4MB = 4GB per 4MB write → OOM on mkfs.ext4.

Root cause: flusher assumed 1:1 dirty-block-to-WAL-entry mapping.
WriteLBA supports multi-block writes but the flusher never deduplicated
shared WAL offsets.

Fix: deduplicate WAL reads by WalOffset in flushOnceLocked(). Multiple
dirty blocks from the same WAL entry share one read buffer and one
DecodeWALEntry call. Memory: O(WAL_entries × size) not O(blocks × size).
For a 4MB write: 4GB → 4MB.

Verified on hardware (m01/M02 25Gbps RoCE):
- Before: mkfs.ext4 → VS RSS 100MB→25GB → OOM killed
- After: mkfs.ext4 → VS RSS 129MB stable, mkfs succeeds
- pgbench TPC-B c=4: 1,248 TPS (RF=1, previously blocked by OOM)

Tests added:
- flusher_test.go: flush_multiblock_shared_wal_read (16 blocks share
  one WAL offset, flush dedup verified)
- flusher_test.go: flush_multiblock_data_correct (3 mixed multi-block
  writes, all data correct after flush)
- test/component/large_write_test.go: 7 component tests (single 4MB,
  sequential mkfs sim, concurrent, mixed sizes, production volume,
  flusher throughput 30s sustained)
- iscsi/large_write_mem_test.go: 2 iSCSI session memory tests (4MB
  R2T flow, slow device)

Testrunner enhancements (same commit — all tested on hardware):
- discover_primary action: maps primary IP → topology node name,
  supports alt_ips for multi-NIC (RoCE + management)
- NodeSpec.AltIPs field for multi-NIC node identification
- 5 new YAML scenarios: ec3, ec5, degraded sync_all/best_effort, pgbench
- All 13 hardware-verified scenarios PASS

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-02 14:24:10 -07:00
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