My VPS is limited to 128 semaphores, which usually get finished within 3 days. I had to delete them and restart apache in order to enter sites hosting on this VPS.

this post explains much of what i face as well http://beau.org/pipermail/whitebox-users/2004-July/002269.html

My question is what is Semaphore? What casues it to end up within 3 days and how i can improve performance of my VPS?

Thank you in advance.

Here is statistics that i get when via SSH i make a command
ipcs -u

-------Semaphore Status --------
used arrays = 93
allocated semaphores = 93

Semaphore's are what the system uses to run processes, kind of like inodes on a disk, there are a limited number of Semaphore's available to access by files at any given time. Usually when Semaphore's are completely used it is because a software application exited and did not clean up when it was done, or there are too many applications using them at any point in time.