If calls to VSS management interface APIs are made while protected snapshot replications are occurring, the APIs encounter performance issues in Windows Server 2008 and in Windows Vista SP1

Consider the following scenario:

• You are running a Windows Server 2008-based or Windows Vista Service Pack 1 (SP1)-based system.
• On this system, an application or service calls Volume Shadow Copy Service (VSS) management interface APIs.
• These VSS management interface APIs are called while many snapshot replications are occurring.
• The snapshot replications are in protection mode.

In this scenario, the VSS management interface APIs encounter performance issues, or these APIs time out. Therefore, applications that call these APIs also encounter performance issues or job failures.

For example, assume that you perform a Bare Metal Restore (BMR) for a Windows Small Business Server (Windows SBS) 2008-based system. Then, you use Windows Server Backup (WSB) to perform a backup operation after the BMR operation. In this situation, the first attempt fails and generates the following error message:

This issue occurs because a performance bug in VSS causes opening operations to take a long time when there are many existing shadow copies. In the example in the "Symptoms" section, the WSB operation uses System Provider of Volume Shadow Copy Service (VSS) to create a shadow copy during the backup process. When the first instance of a shadow copy is created after a BMR operation, this triggers the opening operations for existing shadow copies on the mounted volumes. Therefore, an operation time-out occurs in WSB and eventually causes the backup process to fail.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the �Hotfix Request� page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

Prerequisites

To apply this hotfix, you must have Windows Server 2008 or Windows Vista SP1 installed.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other previously released hotfixes.

Registry information

To use this hotfix, you do not have to make any changes to the registry.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2008 and Windows Vista note

The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately. MUM and MANIFEST files, and the associated security catalog (.cat) files, are critical to maintaining the state of the updated component. The security catalog files (attributes not listed) are signed with a Microsoft digital signature.

For all supported 32-bit versions of Windows Server 2008 and of Windows Vista

For all supported 64-bit versions of Windows Server 2008 and of Windows Vista

For all supported Itanium-based versions of Windows Server 2008

To work around this problem, run the backup process again.

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

Previously, restoring the complete system required that you first reinstall the operating system and then restore the data. However, in a BMR, you can start the system from the operating system CD and then use an ASR floppy disk to recover the system directly from a backup.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information for Windows Server 2008 and for Windows Vista

Additional files for all supported 32-bit versions of Windows Server 2008 and of Windows Vista

Additional files for all supported 64-bit versions of Windows Server 2008 and of Windows Vista

Additional files for all supported Itanium-based versions of Windows Server 2008