System Design the Agentic Way — Phase 3: Data Storage Trade-offs

Phase 3 of System Design the Agentic Way examines data storage trade-offs and durability. It analyzes what the promise of saved data actually costs and explores where writes are processed across four layers. The text distinguishes between write() and fsync, comparing process crashes against power loss. Additionally, it evaluates the durability window, the role of the Write-Ahead Log, and the specific performance differences regarding write amplification between B-tree and LSM storage engines.