Analyze SharePoint web app pool memory leak, crash, performance issues using Debugdiag tool

I recently came across multiple issues related to w3wp process of SharePoint web application pool where you see w3wp process is crashing, app pool get disabled/down, w3wp process does not respond to new user web request, slow performance. That is when, debugdiag came handy to diagnose the problems.Just download and install the debugdiag 1.2 and follow below instructions.

1.       Create a Crash Rule in Debug Diagnostic 1.2 with the following steps:

a.       Open DebugDiag (Start -> Programs -> Debug Diagnostic Tool 1.2)

b.      Select "Crash" and click Next

c.       If the crashing process is w3wp.exe then choose the option  A specific IIS application pool and click Next and choose the application pool that is crashing from the list and click Next. (Note: The Application pool list may be empty if the IIS 6 Metabase Compatibility is not installed. In such a case you can always type the name of the application pool and click Next)

d.      If the crashing process is not w3wp.exe then choose the option A specific process and click Next and choose the process name from the list and click Next.

e.      Click Next in Advanced Configuration (Optional), click on Breakpoints and then click on Add Breakpoint

f.        Choose NTDLL!ZwTerminateProcess from the list and change the Action Type to Full User Dump and Action Limit to 5 and click on Ok. Once you hit OK, the window should look like this.

g.       Click on Save and Close

h.      Click Next for "Rule Name". The "Userdump Location" can be changed here.

i.         Select "Activate the rule now" and click Finish

1.       Notice the Status is Active. The Userdump Count will increase each time a dump file is created.

2.       Wait for the issue to happen..