Troubleshooting ASP.Net Application Pools on IIS6

[Littlejohn2003]

I have several sites running on Windows 2003 Server in true IIS 6 mode
with Application pools. One site has about 9 Virtual Directories in
it that are all configured to run as applications. Each of these have
a dedicated application pool with all different memory settings in the
Memory Recycling area.

The applications are all .Net based applications. They are all pretty
frequently used apps and as a rule of thumb, we assigned more memory
in the app pools to the busier sites and less to the least busy sites.

Here's the deal. Every once in a while, the application will hang up
and not respond. Once I recycle the application, it's fine.
I don't really get a whole lot of info from the developers other than
"The site is hung up" The only thing I see is stuff like this in the
eventlog. This is usually AFTER I recycle the application and it
start working again.

----------------------------------------------------
Event Type: Warning
Event Source: W3SVC
Event Category: None
Event ID: 1013
Date: 11/18/2004
Time: 2:37:21 PM
User: N/A
Computer: <server name>
Description:
A process serving application pool <app name>' exceeded time limits
during shut down. The process id was '344'.

For more information, see Help and Support Center at

http://go.microsoft.com/fwlink/events.asp.

----------------------------------------------------


I'd like to know what I can do to troubleshoot this. Is there any
other logs I can check? Are there any diagnostic tools that I can
check?