Unfortunatly this is somewhat of a vague question. But one i face every now and then.
Right now my server is a fully managed CentOS 5 - Plesk 9.2.1.
In recent days the server keeps choking where apache (or) mysql or both seem to slow down significantly and pages aren't returned or are returned incredibly slowly, restarting mysql helps, sometimes restarting apache helps, and others i need to restart the whole server (SSH starts to really work slow).
So my question is, what would be the process that you debug a webserver for issues of performance where you are getting downtime?
I don't think the server is getting too much traffic (although it is getting consistant traffic) just something seems to kill it...
Where do i start!