Apache performance issue, after "1000 total children" Apache no longer responds to HTTP requests. Not MaxClients issue?

Solution 1:

It is a long shot, but I have had problems like this one. I don't remember exactly what error message it was, but the reason for the problem has always been a buggy PHP program which created recursive requests (i.e. the program requests a URL which in turn re-requests the same URL etc). I have seen this for example in connection with ErrorDocument settings, where the document which should have handled the error was buggy or non-existing and which triggered an error.

You can easily verify if this could be the problem in your access.log: You should have plenty of requests from your server's IP address, all in a very short time. This works until you hit the MaxClients setting or until your system runs out of resources. The only fix is to fix the PHP program in question.