Phase 3: Data Storage Trade-offs

Phase 2 leaned on a shared store and waved at durability — "the data survived a Redis restart" — then admitted the caveat: a graceful shutdown snapshotted to disk, an ungraceful one wouldn't have. Phase 3 goes inside that store and asks the question the caveat was hiding: when you tell a client saved, what exactly did you promise, and what does keeping that promise cost?

Table of Contents

The Question

The Building Blocks: What "Saved" Actually Costs