Check Apache Httpd MPM Config Limits


A little while ago I had to reboot a client’s VM because the web server forked too many processes. They were making use of PHP, but the web server had not been configured for the resulting larger process size. I searched for a tool that would analyze the size of running httpd processes, and project the impact of starting the maximum number of processes allowed by MaxClients or ServerLimit, but didn’t find anything, so ended-up writing my own.

The following script compares the size of running Apache httpd processes, the configured prefork/worker/event MPM limits, and the server’s available memory. The script exits with a warning or error message if the configured limits exceed the server’s available memory. does not use any 3rd-party perl modules, unless the --save/days/max command-line options are used, in which case you will need to have the DBD::SQLite module installed. It should work on any UNIX server that provides /proc/meminfo, /proc/*/exe, /proc/*/stat, and /proc/*/statm files. You will probably have to run the script as root for it to read the /proc/*/exe symbolic links.

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