Magnolia's default cache consists of the following submodules:
Cache Browser app — displays the current state of caches on public instances and lets you delete cached items
Cache core — defines what to cache, when to flush the cache, and headers passed to browsers.
Cache Tools app — displays the number of cached elements and lets you flush caches manually.
Ehcache module — default cache implementation. Robust and proven. Does not persist a restart.
Memcached implementation — shared (distributed) cache between instances. Persists a restart.