Configuration
Host: Windows Server 2008 R2 SP1 (x64)
Guests: three Windows Server 2008 R2 SP1 (x64)
Problem
Windows Server Backup fails when guests are active:
Log Name: Microsoft-Windows-Backup
Source: Microsoft-Windows-Backup
Date: 5/20/2012 12:40:59
Event ID: 9
Task Category: None
Level: Error
Keywords:
User: SYSTEM
Computer: host.local-domain.com
Description:
The backup operation that started at ‘2012-05-20T16:38:15.428000000Z’ has failed because the Volume Shadow Copy Service operation to create a shadow copy of the volumes being backed up failed with following error code ‘2155348129‘. Please review the event details for a solution, and then rerun the backup operation once the issue is resolved.
When guest machines are not active, the backup finishes OK.
On host machine, in an elevated command prompt I executed:
C:\Windows\system32>vssadmin list writers
vssadmin 1.1 – Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2005 Microsoft Corp.
Writer name: ‘Task Scheduler Writer’
Writer Id: {d61d61c8-d73a-4eee-8cdd-f6f9786b7124}
Writer Instance Id: {1bddd48e-5052-49db-9b07-b96f96727e6b}
State: [1] Stable
Last error: No error
[...]
Writer name: ‘Microsoft Hyper-V VSS Writer‘
Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de}
Writer Instance Id: {0447e7f8-be3c-4f11-a5b6-0aa3155c06fb}
State: [5] Waiting for completion
Last error: Unexpected error
[...]
It shows that there is a problem with Hyper-V VSS Writer.
So far, I found the following solutions on the Internet:
- http://qa.social.technet.microsoft.com/Forums/en/windowsbackup/thread/5b552457-c8b7-406d-b6bc-339524ea3107 (add space to guest virtual machine)
- http://blogs.technet.com/b/filecab/archive/2009/09/16/diagnosing-failures-in-windows-server-backup-part-1-vss-spp-errors.aspx (general troubleshooting)
- http://207.46.172.166/en-us/library/ee692290(v=ws.10).aspx (general troubleshooting)
- http://support.microsoft.com/kb/2004712 - this one helped me to identify the issue
I performed the following steps:
- Based on link 4 above:
During an online backup Volume Shadow Copy Service (VSS) requires mounting the snapshotted VHDs in order to revert them back to their proper state. If automount is disabled, VSS cannot mount the snapshotted VHDs as required.
To determine if automount is enabled run DISKPART.EXE from a command prompt, and then run the following command without quotes at the DISKPART prompt:
“automount”
which showed that disks were not automounted
2. In elevated command prompt I typed:
MountVol /E
This seems to have fixed my issue as Windows Server Backup work fine on the host machine now.
