I was trying to use httperf to do some benchmarking on my server and the results were pretty dismal - very low connection /response rates and lots of 5xx values. While there was some other stuff running on the machine, its at least a dual core 2.6ghz with 6gb ram and it generally never goes above 1-2% cpu usage so there is a lot of slack.
Its a (suse) LAMP machine with RoR running under a vhost. A coworker did the initial setup, but I'm looking to tweak things as they are starting to get a little slow for the users.
The command I use in a start up script mongrel_rails start -d -e production -p 3000 -n 8 -c /wwwroot/path
I choose the n=8 from something I read over on http://mongrel.rubyforge.org/index.html .. can't recall the exact page but there was an estimate for 8-12 processors. Figured it couldn't hurt.
Actually it can.
http://mongrel.rubyforge.org/docs/how_many_mongrels.html
We found that 4 was our sweet spot. 5 was too many.
-philip