Choose memcached as the default cache because it keeps the cache boundary clear.
It offers no persistence, so your app must rebuild cached values from the source of truth after a restart or eviction. It also pushes failure handling into client code, so engineers must decide how the app behaves during a cache miss, timeout, or outage.
With Redis, teams can add persistence, replication, and richer data structures, then start depending on the cache like a database without giving it the care a database needs.
