> Considering the first point we decided to give up external caches like Redis, Memcached or Couchbase mainly because of additional time needed on the network.

> Considering the first point we decided to give up external caches like Redis, Memcached or Couchbase mainly because of additional time needed on the network. Uh... we regularly get performance better than what the OP has described in their "needs" with Redis. It can run in memory - on the same machine and has plenty of HTTP frontends you can work on (not a lot of networking).