Running Debian Squeeze on a server with 16GB of RAM. Server handles web server, mail server, DB server but I am currently busy setting it up so its almost not in use, so far only this test site has been put in place until its final configuration. so far I have followed a lot of your tutorials and ended up with: MYSQL – tuned nginx + php5-fpm – tuned, using on_demand process manager + sockets not TCP/IP + APC + WP object caching to APC APC + fast_cgi caching to tmpfs so to admire my work I tried running an ab test from another server: and it ends with: apr_socket_recv: Connection reset by peer (104) so I googled that error, then checked my error logs on the tuned server and found LOADS of these: So what’s the story here? Clearly ab should be served from the fastcgi_cache so what is failing me here? I have attempted to tune networking parameters via sysctl: During my first test, the page was not in cache so when I first ran the ab test I saw a huge CPU spike but when I tried the test again, no cpu spike since the requests were being server from the fastcgi_cache. Also if I stop php5_fpm and open the page in a browser, I'm getting the cached version so the cache works just fine.