LESSONS LEARNED FROM RUNNING REDIS AT SCALE

Summary from the TLDR Web Dev newsletter

Mattermost scaled to 100,000 users by integrating Redis as an external cache, solving scaling bottlenecks caused by their previous in-memory LRU cache and its inefficient cache invalidation process. Optimizing Redis usage involved choices like selecting the `rueidis` library, mandating pipelining and client-side caching for reduced latency and syscall overhead, and using `MGET`/`MDELETE` for efficient bulk operations.