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How to use Windows Server Backup with DAG members

When your Exchange Server is part of a Database Availability Group, the Exchange Writer can lead to your Windows Server Backup failing. Here's how to resolve this issue.

All backup tools are not created equally. When your tight budget requires you to depend on Windows Server Backup, there might be issues. For instance, if you try to use the tool on a server that is part of a Database Availability Group (DAG), the slightest inconsistency in the Exchange data can cause the backup to throw errors, which will cause the backup to fail.

Here's why this happens: When you're using Windows Server Backup, there are a number of moving parts, including the Volume Shadow Service (VSS) writers; these small services allow applications to take advantage of the larger VSS server. There are numerous writers that work with Windows Server Backup, and one that can give you fits when your Exchange Server is part of a DAG is the Exchange Writer. When an inconsistency is found in a mail store, the writer will fail (this is especially true when the DAG hosts active and passive database copies), and your backup will fail. The only thing you can do is disable the Exchange VSS writer on the server to be backed up. I'll walk through this process so you can get your Windows Server Backup churning away on your Exchange server.

Caution: The process requires editing the Windows Registry, and I highly encourage you to back up your registry before making any changes. If you incorrectly edit the Windows Registry, it can cause catastrophic problems on your server.

Step 1: Open the Registry Editor

Click Start and then enter the command regedit in the Run dialog. Once the new window opens, navigate to HKEY_LOCAL_MACHINE | Software | Microsoft | ExchangeServer | v14 | Replay | Parameters (Figure A). Figure A

Do not delete any of the current DWORDS. (Click the image to enlarge.)

Step 2: Add a new DWORD

Right-click the right pane and select New | DWORD. In the resulting window (Figure B), enter the following:
Value Name: EnableVSSWriter

Value Data: 0

Base: Hexadecimal
Figure B

Once you enter the correct information, click OK to finish the edit.

Step 3: Exit the Registry Editor

After all the correct changes have been made, click File | Exit to close out of the editor.

Step 4: Restart Microsoft Exchange Replication Service

Click the Start button and enter services.msc in the Run dialog. In this new window, search for the Microsoft Exchange Replication Service (Figure C). Right-click that entry and select Restart. Figure C

You can also restart the service by selecting the entry and clicking Restart above the service description. (Click the image to enlarge.)

Your Windows Server Backup should start working again. You can run a Backup Once test by opening up the Windows Server Backup tool and clicking Action | Backup Once. Run this backup with the settings from the scheduled backup, and if it succeeds, congratulations!

Note: If you opt to use a third-party backup solution, you will want to delete the DWORD you created and then restart the Microsoft Exchange Replication Service.

About

Jack Wallen is an award-winning writer for TechRepublic and Linux.com. He’s an avid promoter of open source and the voice of The Android Expert. For more news about Jack Wallen, visit his website getjackd.net.

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