pileup of httpd processes in RUN state

[Luke Smith <luke.thomas.smith@xxxxxxxxx>]

I have an on-again-off-again problem with httpd procs in RUN state piling up and choking the server. My load goes over 100, CPU and memory are consumed, and the site goes down. I can't isolate why it happens at some times and not others. I feel like I must be committing some basic config error. Does anyone recognize this pattern? Is there a setting that I'm missing? I have tried to set things reasonably in httpd.conf:

[snip]
ServerRoot "/usr/local"
Listen 80

      Timeout 300
      KeepAlive On
      MaxKeepAliveRequests 100
      KeepAliveTimeout 15
      MinSpareServers 16
      MaxSpareServers 64
      StartServers 16
      MaxClients 256
      MaxRequestsPerChild 10000
[/snip]

Do I need to put this in the various vhosts, too?

Apache 2.2, mod_php / PHP 5.3, FreeBSD 7.1, Drupal site, also Wordpress, 2GB RAM.

I have the exact problem that this person had years ago:

http://mail-archives.apache.org/mod_mbox/httpd-users/200605.mbox/%3C3aaaa3a0605242302n188c8f98r5308d3cee858b22c@xxxxxxxxxxxxxx%3E

[snip from old question]

Every now and then the httpd processes all get stuck on RUN state and start piling up eventually causing swapping but when things are normal the server has a lot of free ram and is far from swapping. 2 gig ram and normal use under 1 gig.

When they are all in RUN state the server is unresponsive on http or very slow and ssh is fine but a bit slow. The way out is killall -9 httpd and then it usually runs ok for a while again, this behaviour started occuring out of nowhere without me doing anything no config change etc,

I suspect a few things, one been mysql since the 2 busiest sites are forums and the other been the hard drive as I noticed weird pauses when doing tasks every now and then even when the server is low load.

What also makes me suspect the hd is that cpu usage is often high on system especially when its clogging up, system is often higher then user.

[/snip]

Thanks --

 Luke