Exchange 2007 Service Pack 2 introduces the ability to take Exchange-aware, VSS backups on Windows Server 2008. This is via a plug-in to the Windows Server Backup tool that is native to the operating system. For those who are not aware of this functionality, you can read more about it here:
Using Windows Server Backup to Back Up and Restore Exchange Data
Notice the last bullet point on this page, though:
"The plug-in does not support the Exchange Replica VSS Writer that is part of the Replication service. As a result, you cannot use Windows Server Backup to backup passive copies of storage groups."
Your first thought in reading this may be simply that you cannot backup the passive node of a Cluster Continuous Replication (CCR) cluster with Windows Server Backup. However, this also applies to standalone servers that are Standby Continuous Replication (SCR) targets or that have Local Continuous Replication (LCR) enabled. When Windows Server Backup processes a backup of a server with LCR or SCR enabled, it calls the VSS Writer from the Replication service instead of the VSS Writer from the Information Store service. Since Windows Server Backup was not designed or tested for use with the Replication Service, the Exchange-aware portion of the backup fails.
The backup will complete, but you will see this error in the status window of the backup job:
The following error event will be logged in the Application Log:
Log Name: ApplicationSource: Microsoft-Windows-BackupDate: 10/14/2009 8:44:53 AMEvent ID: 565Task Category: NoneLevel: ErrorKeywords: User: SYSTEMComputer: server1.domain.comDescription:Consistency check for component '1a0a0e79-76ce-4985-aa99-35f5018b0ed7'\'Microsoft Exchange Server\Microsoft Information Store\SERVER1' failed. Application 'Exchange' will not be avaliable in the backup done at time '10/14/2009 8:44:42 AM'
In order to take an online Exchange-aware backup of a server using LCR or serving as an SCR target you must disable the Replica VSS Writer used by LCR. To do so, follow these steps:
1. Open Registry Editor and browse to the HKEY_LOCAL_MACHINE\Software\Microsoft\Exchange\Replay\Parameters registry key.
2. Add a new DWORD value named EnableVSSWriter and set the value to 0 (zero).
3. Restart the Microsoft Exchange Replication Service.
This will allow Windows Server Backup to use the Microsoft Exchange Information Store service's VSS Writer to perform the backup. You can confirm that the backup was successful by starting the Recovery Wizard in Windows Server Backup and verifying that you are able to select the Exchange application for recovery.
Does making this change affect the normal operation of LCR? Will it continue functioning?
No affect on LCR operation. This simply disables the VSS Writer for the Replication Service. If you implement a third-party backup utility later, you would need to reverse this setting in order to backup the replica copy of the database.
I suppose that the VSS Write for the Replication service need not be disabled if the LCR copy of the database is on a different volume and I do not back up that volume. In othe words: There are no changes necessary in the registry if I just back up volumes that do not contain LCR copies of the exchange databases?
I have a SCC HA setup.
Does this fix have any effect on it also?
This fixed my problem with the consistency check failing for Exchange 2010 in a DAG configuration.
This SMB uses Exchange Server 2007 with SP3 in Active-Passive mode and CCR enabled. There is one Storage Group and a single domain. We are backing the Passive node.
Before applying EnableVSSWriter in the HKEY registry we were in fact seeing backups completing with this error. After applying this recommendation, the backup shows Successful but the log files did not truncate and the partition size remained the same. Are we missing a step in the VSS Backup work flow ?
This SMB uses Exchange Server 2007 with SP3 in Active-Passive mode and CCR enabled. There is one Storage Group and a single domain. We are backing up the Passive node.
I still get the same fail message after the change. Ive restarted the Replication Service however does the server have to be restarted? Any advice appreciated.
Mine used to work after adding this entry, now it still fails with the same error. Any help would be appreciated.