We have an IIS 7.5 web service on Windows Server 2008 that handles WCF requests from C# clients. This service is configured to have Maximum Worker Processes = 1, so it is not a web garden.
IIS is setup to recycle itself at the same time every day (3 AM). I am trying to debug gnarly connection issues, so I wanted to be sure the application pool was not recycling itself. I configured the pool to log an event when it recycles itself.
To my surprise, I see the following entries in the System event log:
Level: Information Date/Time: 3/23/2012 3:00:00 AM - Source: WAS - Event ID: 5076
A worker process with process id of '6636' serving application pool 'MyAppPool' has requested a recycle because it reached its scheduled recycle time.
Level: Information Date/Time: 3/23/2012 2:59:39 AM - Source: WAS - Event ID: 5076
A worker process with process id of '9364' serving application pool 'MyAppPool' has requested a recycle because it reached its scheduled recycle time.
IIS is correctly recycling the application pool at 3 AM. However, I do not understand why I would be getting two recycle events in the log within a few seconds of each other. The maximum number of processes is 1. Does IIS sometimes allocate multiple processes for an application pool that is specified as having 1 process?
-- edit --
I connected at about 4 PM today and only saw 1 w3wp.exe process. There are no other event log entries that would indicate a crash.