Managing Application Pools in IIS 7
Applies To: Windows 7, Windows Server 2008, Windows Server 2008 R2, Windows Vista
An application pool is a group of one or more URLs that are served by a worker process or a set of worker processes. Application pools set boundaries for the applications they contain, which means that any applications that are running outside a given application pool cannot affect the applications in the application pool.
Application pools offer the following benefits:
Improved server and application performance. You can assign resource-intensive applications to their own application pools so that the performance of other applications does not decrease.
Improved application availability. If an application in one application pool fails, applications in other application pools are not affected.
Improved security. By isolating applications, you reduce the chance that one application will access the resources of another application.
In IIS 7, application pools run in one of two modes: integrated mode and classic mode. The application pool mode affects how the server processes requests for managed code. If a managed application runs in an application pool with integrated mode, the server will use the integrated, request-processing pipelines of IIS and ASP.NET to process the request. However, if a managed application runs in an application pool with classic mode, the server will continue to route requests for managed code through Aspnet_isapi.dll, processing requests the same as if the application was running in IIS 6.0.
Most managed applications should run successfully in application pools with integrated mode, but you may have to run in classic mode for compatibility reasons. Test the applications that are running in integrated mode first to determine whether you really need classic mode.
For information about the levels at which you can perform these procedures, and the modules, handlers, and permissions that are required to perform these procedures, see Application Pools Feature Requirements (IIS 7).
This task includes the following procedures: