I am running my own server for 5 months with no problems but yesterday my apache didnt want to start, no errors (only warnings), i have not make any changes to the configuration, I was really scared.
The first thing I tried to do was modify my apache config (/etc/httpd/conf/httpd.conf) after changing and modifying nothing happened.
Then checked my logs /var/log/httpd/ and find:
[Fri Jul 20 18:57:26 2007] [emerg] (28)No space left on device: Couldn’t create accept lock

But I have plenty of disk space, so why this is happening?

There were myriads of semaphore-arrays left, owned by my apache-user.
ipcs -s | grep apache
Removing this semaphores immediately solved the problem.
I just typed this via SSH and the problem was solved:

ipcs -s | grep apache | awk ‘ { print $2 } ‘ | xargs ipcrm sem