One of our production servers started to send out alerts because the memory consumption was too high. A first look at the server showed us that one of the w3wp processes was consuming most of the available resources on the server.
Sidenote: Web applications running within Microsoft’s Internet Information Services (IIS) utilize what is known as IIS worker processes. These worker processes run as w3wp.exe, and there are typically multiple per server.
So we knew that one of our web applications was causing trouble. The question of course now is which one?
As the resource manager only showed us the process id, we couldn’t immediately give the answer. But with some extra command line magic we got the answer.
To get the information we need we used the appcmd utility. This tool allows; among other things; to list the IIS worker processes.
We executed appcmd list wps and got the the list of worker processes with their PIDs.
c:\Windows\System32\inetsrv>appcmd list wps
WP "46848" (applicationPool:BerichtenBox Services)
WP "23640" (applicationPool:ird3graphql)
WP "35632" (applicationPool:VervoerSvc)
WP "28616" (applicationPool:MailService)
WP "46452" (applicationPool:DefaultAppPool)
WP "12612" (applicationPool:arno)
WP "29144" (applicationPool:BIG)
WP "15388" (applicationPool:Toa)
WP "46208" (applicationPool:DocumentStorageServices)
WP "35716" (applicationPool:auth3services)
Now it was easy to map the process id to the correct application pool. Next step is to further investigate why this application was causing such high memory usage but that is maybe for another post…
More information
What is w3wp.exe? - IIS Worker Process Explained (stackify.com)