This is a problem that I have done twice in a couple of months. Basically, I called, saying that our site is giving an HTTP 503 error, I look at the IIS7 manager and notice that AppPool has shut down. I reboot it, and it continues to joyfully continue it until after a few months it repeats itself.
The IIS manager processes four sites, both times this question arose on one site. The version of .NET Framework used is v4.0.
In the event log I see the following
IIS Web Server:
Warning: event 5011, "The process serving the application pool" foo "caused a fatal communication error with Windows Activation Service. The process identifier was" X ". The data field contains the error number." - This warning appears 5 times, with 5 difference values for X, this happens after about 10-15 seconds between each warning.
Error: Event 5002 "Application pool" foo "is automatically disabled due to a series of failures of the process (s) serving this application pool.
Application Log:
Error: Event 1000: "Invalid application name: w3wp.exe, version 7.5.7601.17514, timestamp: 0x4ce7afa2.
Invalid module name: clr.dll version 4.0.30319.17929, tamp time: 0x4ffa59b1. Exception Code L 0x0000fd "
Information: Event 1001 "Error bucket, type 0
Event Name: APPCRASH Response: Not Available "
The above two events occur over the same period of time, first an error, followed by two information events. This happens five times and is queued with alerts from the web server log.
If someone can clarify what is happening, it will be very appreciated. I would prefer not to worry about our site disappearing from the Internet because the application pool decided to shut down.
I know that Rapid Fail Protection (which causes a shutdown after a certain number of failures) can be disabled, but I would rather deal with the main problem.