Have you got this error from Apache?
[notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[error] (28)No space left on device: Cannot create SSLMutex
At first glance it appears that you may be out of disk space but the issue is ipc or interprocess communication.
This will clear out the ipcs processes so things can work, this often happens during high traffic and may be a sign of DDOS.
The command below will fix it, it will list al........
[Wed Jan 08 18:50:07 2014] [emerg] (28)No space left on device: Couldn't create accept lock (/etc/httpd/logs/accept.lock.15449) (5)
This may happen when trying to restart Apache and you find it dies right after starting and check /var/log/httpd/error_logs.
What is the cause of this?
You could be out of disk space (if you're not then see #2 and below)
You're out of Semaphores, you need to kill all the old ones.........