We have an Apache webserver running on CentOS 5.6 (installed via yum). Today we have had an expected influx of new users -- however unexpectedly we seem to have hit a limit of 300 accesses per second -- I have a graph (which Stack overflow is not leting me upload), but it shows that three times today (when our site almost ground to a halt) the "accesses / second" hit 300 and stayed for a while. As I type the current figure is 292.23 and the max today is 300.41.
We are running PHP inside the apache process, and that is connecting to a MySQL server (different physical box). However we're happy that MySQL is responding fine.
We've upped our limits in the httpd.conf from the default 256, however this hasn't had an effect on the magic 300 figure. We've searched both the
httpd.conf file for 300 and cannot find it. Below is the prefork config we are now using:
<IfModule prefork.c> StartServers 8 MinSpareServers 5 MaxSpareServers 20 ServerLimit 400 MaxClients 400 MaxRequestsPerChild 4000 </IfModule>
If anybody has any clue to what is causing this 300 limit I'd greatly appreciate it.