Build a Write-Ahead Log with Snapshots

log replay, snapshots, crash recovery

Challenge 4 of Storage & CachingIntermediate~60 min

Make your KV store survive restarts. Implement a write-ahead log, replay it to rebuild state, snapshot the dataset to compact the log, and recover cleanly even after a crash mid-write.

6 steps

1. 1Append-Only Write-Ahead Log
2. 2Log Set and Delete Operations
3. 3Replay the Log to Rebuild State
4. 4A Durable Key-Value Store
5. 5Snapshots & Compaction
6. 6Surviving a Crash Mid-Write