Microsoft does not support the use of Volume Shadow Copy Service to back up guest machines by way of a Virtual Server 2005 host computer

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INTRODUCTION

Microsoft does not support the use of Volume Shadow Copy Service (VSS) on a computer that is running Microsoft Virtual Server 2005 to back up a running guest virtual machine. If you try to use VSS on a Virtual Server 2005 host computer, your guest backups may be unreliable or corrupted.

Note VSS is supported on Virtual Server 2005 guest virtual machines. Additionally, you can use VSS to back up all other applications on the host computer that support the VSS infrastructure.

MORE INFORMATION

VSS requires a snapshot of the program state. To create this snapshot, the program must typically reach a consistent state and then become inactive to enable VSS to create the snapshot.

Virtual Server programs run in a volatile state because their extensive optimizations deal with large flows of transactions and of messages. Because Virtual Server programs keep data in a constant state of flux between memory and disk, it may be difficult to locate data that must be archived.

Without the support for the interfaces that VSS provides to take a snapshot of the program state, VSS cannot perform the shadow copy of the host computer and guarantee that a consistent state of the guest virtual machine will be obtained. If you use VSS without the support for the interfaces, you may cause data corruption.

Starting with Microsoft Virtual Server 2005 R2 SP1 and for virtual machine guests that support VSS, such as Windows Server 2003, you now have the option for live backup of virtual machines by using backup software that supports Volume Shadow Copy, the new Virtual Server VSS Writer (VS Writer). Be aware that neither Windows Backup (NTbackup) nor Windows Server Backup support the VS Writer. Microsoft Data Protection Manager 2007 will back up virtual machines and the virtual server configuration by using the VS Writer.

The following file is available for download from the Microsoft Download Center:

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Download the Microsoft Virtual Server 2005 R2 Service Pack 1 - Enterprise Edition package now. (http://www.microsoft.com/downloads/details.aspx?familyid=bc49c7c8-4840-4e67-8dc4-1e6e218acce4)

For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 (http://support.microsoft.com/kb/119591/ ) How to obtain Microsoft support files from online services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.

For information about how to back up and restore Virtual Server, see the following Microsoft TechNet Web site:

http://technet.microsoft.com/en-us/library/cc720377.aspx (http://technet.microsoft.com/en-us/library/cc720377.aspx)

For information about how to plan a backup and restore of data, see the following Microsoft TechNet Web site:

http://technet.microsoft.com/en-us/library/cc720328.aspx (http://technet.microsoft.com/en-us/library/cc720328.aspx)