People do all sorts of optimizations over their primary storage layer. AWS has built a whole product around a Redis based caching mechanism (to get sub-millisecond response times)

Their diagram below really outlines the prevalent architecture very well:


  • Client layer with UI’s, apps etc.
  • Storage layer with multiple databases / file-systems
  • Caching layer in between

Writing and managing a caching layer is not easy. Reminds me of the famous CS phrase:

There are only two hard things in Computer Science: cache invalidation and naming things.

– Phil Karlton