6.2 Loss Windows and Choosing Persistence

Choosing a persistence mechanism answers only half of the durability question. The previous lesson showed how Redis writes the order service's 20 GB of carts, sessions and counters to disk: RDB forks a child that snapshots the whole dataset, and AOF appends every write command to a multi-part log that a rewrite compacts. That service receives 5,000 writes per second, so every second of lost data is about 5,000 lost writes.

This lesson measures what each setting can lose and how fast the instance comes back