Storage & Durability
Lesson, slides, and applied problem sets.
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Storage & Durability
Why durability
Crashes happen. Durable systems recover by replaying logs and reconstructing state.
Write-ahead log (WAL)
Persist changes before applying them in memory. On recovery, replay the WAL.
Compaction
Logs and LSM trees merge old data into new, reducing space and speeding reads.
What you will build
- WAL replay to reconstruct a key-value store
- LSM-style run merge (compaction)
- LSM read path with Bloom filters and tombstones
- Multi-way LSM compaction with tombstone GC
Module Items
WAL Replay
Replay a write-ahead log to reconstruct key-value state.
LSM Compaction Merge
Merge two sorted runs, applying overwrites and tombstones.
LSM Read Path
LSM Multi-Way Compaction