<b>This week in caching: making your cache observable</b>

<b>This week in caching: making your cache observable</b>
You can't tune what you can't see. Curated:
— <i>The four numbers to graph</i> — hit ratio, eviction rate, memory used vs max, and average key age; what each one tells you when it moves.
— <i>Eviction rate as an early warning</i> — why a climbing eviction rate predicts a hit-ratio cliff before users feel it.
— <i>Per-key-pattern metrics</i> — instrumenting cache calls by key prefix so you find the one namespace thrashing your whole instance.
— <i>Redis INFO and keyspace hits/misses</i> — the built-in stats most people never query.
— <i>Latency, not just hit rate</i> — when a 'fast' cache is slower than the DB for tiny payloads.
Credits to the Datadog Redis dashboards and Grafana community boards.
Bookmark: the eviction-rate-as-canary piece — the metric that warns you a day before the incident.