I recently built a site which uses mod_perl to segment content to different user groups, and has a CMS backend. At first I had the MaxClients set to 50, and that turned out to be not nearly enough, from there we moved it to 100, which also wasn't enough. We settled on 125.

Of course this does not mean that there are always 125 child processes serving 125 concurrent requests. But on average, there are between 50-100 processes running at any given time serving concurrent requests. The site regularly gets anywhere between 900-1400 unique homepage hits per day, most of which are concetrated between 8 a.m. and noon. And being an intranet site, it is actually read/used by its users. Most sessions run approx. 20 minutes to an hour.

If I could have, I would have load balanced it, yadda yadda yadda, but economics and politics dictated that it had to run on a single dedicated Linux box with a shitload of RAM (I wasn't even allowed to put the MySQL DB on its own machine, it shares the same box).

The site has had no issues, its response time is excellent, and there has been no complaints at all. Take note that this was a transparent replacement of an existing static HTML site, so users expectations on performance were pretty high.

While I was pretty happy with the results, I would not call myself a genius.

;-)

UPDATE: Oops, the site is actually running on FreeBSD, it was late last night when I posted this. I like Linux, but i gotta give credit where credit is due. (FreeBSD 4.7-RELEASE-p22 to be exact)