[calloc]

The only reason I still run Apache is because a lot of PHP stuff requires mod_rewrite to create pretty URL's and I haven't had the time to rewrite them using LUA so I can use Lighttpd.

But on the same server, using PHP-FPM with FastCGI on both lighttpd and Apache I am serving almost 4x the requests that Apache is serving with less memory overhead. Switching the sites that are currently running on Lighttpd back to Apache as I attempted to do not to long ago to only have to maintain a single server made Apache die a miserable fast death. It just could not keep up, I've had friends look over my config (datacenter techs, help people scale their stuff, porn mostly) and they said it looked fine. Apache was the limiting factor here.

I moved from prefork to threaded, that helped a little, but not much. Apache was just using a lot of memory, and overall did not provide the performance I wanted. Switched back to lighttpd, load on the server went down, and the websites were responsive as before.

[powertower]

"made Apache die a miserable fast death. It just could not keep up, I've had friends look over my config (datacenter techs, help people scale their stuff, porn mostly) and they said it looked fine."

Apache crashing under load is indicative of seriously bad MPM settings: specifically the # of processes / threads allowed to be used (and some other settings such as KeepAlive timeout, how php is being used, etc).

With a properly configured MPM, anything coming over the process / thread limit goes into a backlog queue which is 511 entries long. Anything over this just gets dropped.

To iterate, Apache does not crash under load (too many requests), it crashes due to too many processes / threads (an MPM setting) being used and sometimes due to leaking modules such as mod_python/ruby.