===== What to Do When Apache Runs Out of Semaphores =====

Taken from [[http://bergie.iki.fi/blog/if-your-apache-ever-runs-out-of-semaphores---/]]

If you get this error message when trying to start Apache, then you're out of [[http://en.wikipedia.org/wiki/Semaphore_(programming)|semaphores]]:

  #apachectl start
  Ouch! ap_mm_create(1048576, "/var/run/httpd.mm.22903") failed
  Error: MM: mm:core: failed to acquire semaphore (No space left on device): OS: Invalid argument
  /usr/sbin/apachectl start: httpd could not be started

The easy fix is to just remove all semaphores owned by Apache:

# /usr/bin/ipcrm sem $(/usr/bin/ipcs -s | grep apache | awk '{print$2}')

Got the fix from [[http://forums.cacti.net/about675.html|cacti forum]].