It turns out that most caching algorithms we use in practice (CDNs, memcached, storage, etc.) are still pretty far from the optimal hit ratio/ miss ratio. See,

It turns out that most caching algorithms we use in practice (CDNs, memcached, storage, etc.) are still pretty far from the optimal hit ratio/ miss ratio. See, e.g., recent work that exposes that gap (I'm an author) https://www.cs.cmu.edu/~dberger1/pdf/2018PracticalBound_SIGMETRICS.pdf https://www.cs.cmu.edu/~dberger1/pdf/2018PracticalBound_SIGM... https://github.com/dasebe/optimalwebcaching https://github.com/dasebe/optimalwebcaching