It this patch specific to 10.1.1? I just upgraded a server that had been a fresh install of 10.0.1 to 10.1.1 last night, centos 5.5, and now I'm having the same exact issue as everyone else in this thread; a change to a plan or a new plan and apache doesn't restart on its own.
Edit: Actually after putting that new file in place, the watchdog seems to kill apache off every minute and then can't restart it, so much for that idea.
Following up, 10.0.1 we were stable, and watchdog was not running. After upgrading to 10.1.1, any change in plesk that requires an apache restart leaves apache not running. Trying to use watchdog to fix the issue results in watchdog causing apache to die off and NOT restarting, umm, yeah, kind of the opposite of what the program is supposed to do. With watchdog active, you get this in the logs when apache dies off:
[Tue Feb 01 19:00:24 2011] [emerg] (43)Identifier removed: couldn't grab the accept mutex
[Tue Feb 01 19:00:24 2011] [emerg] (43)Identifier removed: couldn't grab the accept mutex
[Tue Feb 01 19:00:24 2011] [emerg] (43)Identifier removed: couldn't grab the accept mutex
[Tue Feb 01 19:00:24 2011] [emerg] (43)Identifier removed: couldn't grab the accept mutex
[Tue Feb 01 19:00:24 2011] [emerg] (43)Identifier removed: couldn't grab the accept mutex
[Tue Feb 01 19:00:24 2011] [emerg] (43)Identifier removed: couldn't grab the accept mutex
[Tue Feb 01 19:00:24 2011] [emerg] (43)Identifier removed: couldn't grab the accept mutex
[Tue Feb 01 19:00:24 2011] [emerg] (43)Identifier removed: couldn't grab the accept mutex
[Tue Feb 01 19:00:24 2011] [emerg] (43)Identifier removed: couldn't grab the accept mutex
[Tue Feb 01 19:00:25 2011] [emerg] (22)Invalid argument: couldn't grab the accept mutex
[Tue Feb 01 19:00:25 2011] [emerg] (22)Invalid argument: couldn't release the accept mutex
[Tue Feb 01 19:00:26 2011] [emerg] (22)Invalid argument: couldn't grab the accept mutex
With watchdog disabled, at least your web server continues running, until someone changes something that requires an apache restart, then its down until your monitoring system pages you so you can manually restart it; that's great.