Which process running on an IIS server spawns a w3wp.exe for each asp.net application?

Which process running on an IIS web server is responsible for the creation of w3wp.exe worker processes for each asp.net开发者_运维知识库 application?

With IIS 7, the actual process that creates the w3wp.exe (worker process) is known as the IIS Windows Process Activation Service (WAS):

Windows Process Activation Service (WAS) manages application pool configuration and the creation and lifetime of worker processes for HTTP and other protocols. The World Wide Web Publishing Service (W3SVC) and other services depend on WAS.

If you use a tool such as Process Explorer you can see the process tree including the parent process of your w3wp3.exe:

A w3wp.exe process is started for each app-pool that you have running.

There is also a process started for each element of a web-garden that you are running.

Just thought I'd throw in a little extra I've just found - we have a test IIS server that is inactive 90% of the time and although it has 6 application pools that are started according to the IIS management console, there were no instances of w3wp.exe running. Once I actually opened the website in my browser it spawned an instance to serve the request.