In my personal experience, the first step in tuning Apache was "put a nginx server in front of it". Running out of workers (either processes in the prefork mode

In my personal experience, the first step in tuning Apache was "put a nginx server in front of it". Running out of workers (either processes in the prefork model, or threads otherwise) was in my experience way too easy, especially when keepalive is enabled (even a couple of seconds of keepalive can be painful). The async model used by nginx can handle a lot more connections before running out of resources.