Unresponsive Apache server problems

I have used Apache for years and lately I have started to have problems
with the server becoming unresponsive. It happens sporadically and it
appears to be as a result of certain kinds of traffic. I just cannot
seem to figure out what is the exact cause or how to fix it.

I am running Apache 2.2.3 on FreeBSD 5.3 and here is the MPM
configuration which is where I have tried to resolve the issue.

<IfModule mpm_prefork_module>
StartServers 7
MinSpareServers 10
MaxSpareServers 50
MaxClients 60
MaxRequestsPerChild 250
</IfModule>

I have tried many variations. What I had by default after the install
was too many children to the point that it was swapping out memory to
disc which was the cause for the slow-down then. What I have been
seeing in my access log during the current slow downs is hits on my
WordPress comment posting script. I have seen blocked access to that
URL and placed the script in a different location. It appears that
there are lots of bots all over which still hit the old URL. But there
are not many hits on this URL which would overwhelm it. At least the
number of hits is not high. Maybe the amount of data posting to the
URL is significant.

Note: I would run Apache in the threaded model to conserve memory but
it seems FreeBSD 5.3 is not ready for that. My hosting provider does
not offer the more current FreeBSD version yet. For now I have to
stick to the forked model which chews up all of that memory.

Right now the web server is sluggish but the CPU load is hanging around
zero. That tells me there is some sort of I/O blocking happening
withing the web server. Either it is queuing up tons of requests and
it is taking a long time to handle them, or something else is going
wrong.

I look at the server status and I cannot make sense of it. It does not
look any different than I have seen over the last several years.

I have installed mod_dosevasive 2.0 to detect DDOS activity and it
occasionally appends addresses to a log. In 2 weeks there are only 10
entries. That does not seem like a lot of traffic from bots, so it
indicates to me that I need to look elsewhere.

Has anyone had this problem? What can I do?

Brennan Stehling
http://brennan.offwhite.net/blog/