[mdlug] [Apache] High Load Issues... ?

[Wojtak, Greg]

I recently updated from RHEL 4 to CentOS 5, taking Apache along for the ride (2.0 -> 2.2).  Recently (only in our production environment), we've been seeing load randomly shoot up to around 130 or so.  One of the things I've noticed is that during these occurrences, apache is always on top when running top, though it is always different PID's, and (this is the one that gets me) memory utilization drops tremendously.  I assume there is some kind of garbage cleanup going on.   Does anyone know what apache might be doing that frees up approximately 200 MB or more of physical RAM?  Any other insights?

The only other information I can provide is that it is a Linux/Apache/MS-SQL/PHP set up.  We've tried duplicating this in our test and beta environments without success, so it is hard to get a handle on what is going on.  We're fairly certain it's not a high traffic situation, since each of our 4 web servers is running less than 100 httpd procs at any given time and we can generate far more "traffic" in our beta environment than prod ever sees.

Any ideas?

Thanks!

Greg Wojtak