Which application pool is it?

If you are running multiple web sites on your IIS web server you will eventually need to know which worker process is associated with a particular application pool.  It may be for baseline information or troubleshooting but at one point or another you will need to cross reference an application pool to a w3wp worker process.

Opening up Task Manager and clicking on the Processes tab presents you with a view like this.  As you can see, it’s not real easy to tell which application pool you are looking at when referencing the resource usage of a w3wp worker process .  Sometimes the User Name helps to narrow it down but what do you do if there are a few different processes using the same User Name?  There is a tool for that.

In IIS 7 you can use the command-line tool, appcmd.exe.  By entering “appcmd list wp” without the quotes into a command prompt window, you will get a list of worker processes, their Process IDs, and the name of the application pool.  You should note that if you are on an IIS 6 server, the command is “iisapp” without the quotes.

This is great but we still don’t have all the information needed to cross reference the application pool to Task Manager.  The next thing we need to do is go back to the Task Manager menu and click View -> Select Columns.  That will bring up a new window.  Check the box on the first field, PID (Process Identifier).  Then click OK.

Going back to Task Manager we can see that there is a new column, PID.  The value in this column can be cross referenced to the Process ID that was returned from appcmd.  Using this information we can easily track down the application pool that we are looking at in Task Manager.

Rick is a Senior Support Lead at OrcsWeb, a hosted server company providing managed hosting solutions.