Difference between IIS7 Website Reset and IIS7 Website Stop / Start

Question

I have a web site with a DLL issue (we developed the DLL as part of the application). At some point, the DLL becomes corrupted and is unable to perform its' task properly from that point forward across the entire site to all users, even though the corruption is caused by a single user session (I assume)

Through the IIS7 GUI, if I restart the web site: Manage Wesbite --> Restart the problem is still present. If I however Stop and Start the website: manage Website --> Stop then Manage Website --> Start something is cleared and the problem goes away .... until the next time

Obviously I need to track down the cause of the corruption, and happy to listen to any ideas you might have, but I am interested also in the difference between what is actually happening when I reset and when I start / stop

Regards, Mark

Answer 1

To completely clear out bad settings in memory you should perform an application pool recycle. That restarts the actual w3wp.exe worker process.

Restarting the website is a brief change that doesn't really restart the app pool. Stopping and starting must be long enough to allow the app pool to stop, but it's not consistent either.

To recycle the app pool, find which app pool your site is using with the "Basic Settings" link under the Actions pane. Then from the Application Pools section you can restart your app pool.

Check out Week 16 of my video series. It explains app pool recycles in more depth.

As for the actual root cause, Debug Diag is a good tool that will allow you to get a memory dump when the issue occurs. That will hopefully give you enough clues on the root issue.