FIX: Memory leak in Rhs.exe after you configure the IIS 7.5 W3SVC service in a Windows Server 2008 R2 SP1 failover cluster

Symptoms

After you use the Clusweb7.vbs script to configure the following service in a Windows Server 2008 R2 Service Pack 1 (SP1) failover cluster, a memory leak occurs in the Resource Hosting Subsystem (Rhs.exe) process:

• Internet Information Services (IIS) 7.5 World Wide Web Publishing Service (W3SVC) 
  

Therefore, the Rhs.exe process continuously increases its memory usage.

When this issue occurs, an out of memory condition may occur in the clustered W3SVC service.

Notes

• The Clusweb7.vbs script is described in the Microsoft Knowledge Base (KB) article 970759.

• This issue does not occur when you use IIS 7.5 in a Windows Server 2008 R2 failover cluster.

Cause

This issue occurs because the memory of IAppHostElement objects is not released.

When the Clusweb7.vbs script runs, the GetAdminSection function allocates memory to merge one or more individual IAppHostElement objects. These objects are used at one or more locations in the path hierarchy. However, the memory for these objects is not released. Therefore, the memory leak that is described in the "Symptoms" section occurs when the LooksAlive function in the Clusweb7.vbs script calls the GetAdminSection function.

Note This issue occurs in only Windows Server 2008 R2 SP1 because the GetAdminSection function is internally introduced as a new feature in Windows Server 2008 R2 SP1.

Resolution

Status

Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.

Workaround

To work around this issue, restart the computer that is running the IIS service. 

More Information

To reproduce this issue on an IIS 7.5 server in a non-cluster environment, run the following script that is in the Clusweb7.vbs script:

SITES_SECTION_NAME = "system.applicationHost/sites" APPLICATION_POOLS_SECTION_NAME = "system.applicationHost/applicationPools" CONFIG_APPHOST_ROOT = "MACHINE/WEBROOT/APPHOST" Do LooksAlive() WScript.Sleep(500) Loop Function LooksAlive( ) Dim adminManager, index Set adminManager = CreateObject("Microsoft.ApplicationHost.AdminManager") Set sitesSection = adminManager.GetAdminSection(SITES_SECTION_NAME, CONFIG_APPHOST_ROOT) set configSection = adminManager.GetAdminSection(APPLICATION_POOLS_SECTION_NAME, CONFIG_APPHOST_ROOT) Set adminManager = nothing End FunctionNote When you run this script, a memory leak occurs in the Wscript.exe process. You can use Task Manager to monitor the memory usage of the Wscript.exe process.

For more information about the Clusweb7.vbs script, click the following article number to view the article in the Microsoft Knowledge Base:

970759 Configuring IIS 7.0 World Wide Web Publishing Service in a Windows Server 2008 failover cluster
Note The article 970759 applies to also Windows Server 2008 R2.

A similar issue occurs when you use Internet Information Services (IIS) 7.0 in a Windows Server 2008 failover cluster. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

2163398  A memory leak occurs in the Rhs.exe process when you configure IIS 7.0 World Wide Web Publishing Service in a Windows Server 2008 failover cluster