Hello,

I relise that it may have been hammered on quite a few times already, but I cannot understand the results I'm getting. I have a rather basic setup on Ubuntu Server 11.04, where nginx (run as root) spawns 2 worker_processes and serves a basic HTML page. Each of these processes should have its worker_connections set to 8192. There's no limit_zone defined. worker_rlimit_nofile is set to 65536, keepalive_timeout 5.

Verifying max load, I run ab from another server on the subnet. It works fine with "ab -kc 8000 -n 16000 http://10.1.1.10/". However, when I do "ab -kc 10000 -n 16000 http://10.1.1.10/", ab shows about 3486 failed requests in its results (Length: 1743, Exceptions: 1743), while nginx's error.log features numerous "2011/10/11 16:49:24 [alert] 12081#0: 8192 worker_connections are not enough" errors.

Testing a number of settings, it seems that there's a close to 1-1 relationship between worker_connections and the maximum concurrency parameter to ab that doesn't produce errors. I tried setting worker_processes to some high number (like 16), but it seems to have no effect whatsoever.

Can you please let me know why this setup might not be serving the "promised" ;-) worker_processes * worker_connections connections? Is it possible that new connections are not being evenly distributed to the two processes? Apologies if this is some basic error on our side, we're still learing (and admiring) nginx and are more used to IIS!

Kind regards,
Dawid Ciecierski