IIS Worker Process
Applies To: Windows Server 2008
An Internet Information Services (IIS) worker process is a windows process (w3wp.exe) which runs Web applications, and is responsible for handling requests sent to a Web Server for a specific application pool.
The following is a list of all aspects that are part of this managed entity:
Internet Information Services (IIS) worker processes serve an application pool and can be in a starting, running, stopping, or unknown state. In IIS 7.0, worker processes are managed by WAS (the Windows Process Activation Service). If a worker process fails to respond, it may be recycled by WAS.
In Internet Information Services (IIS) 7.0, worker processes can trace request activity. Of the requests that reach the worker process, you can log successful requests, failed requests, or all requests. In order to log this information, the worker process identity must have permissions to create directories and subdirectories, and to write files to the directory configured for the site.