The Exchange plugin (data source) creates a snapshot of the Exchange information store using the Microsoft Volume Shadow-Copy Service (VSS).
In order for this to be successful, the following services need to be running:
- Microsoft Exchange Information Store (store.exe, the main service of Exchange)
- Volume Shadow Copy (the plugin/data source creates a snapshot of Exchange database using VSS)
- Microsoft Software Shadow Copy Provider (the writer used to work with Exchange by VSS)
The Exchange writer must be in a stable state before starting a backup. This is normally the case, but to check, run the following command from the command line:
vssadmin list writers
If it is not stable, then you need to restart the Microsoft Exchange Information Store service accessible from the Services console - Start/Run/services.msc
Should other (third party) VSS writers be present (for example: Acronis or Symantec), then it is imperative that the standard Microsoft Software Shadow Copy Provider has a higher priority than the others. This can be checked by the following registry key:
Any third party writers should be set to 0 and only Microsoft should be set to 1. If you make any changes, you need to restart the Microsoft Volume Shadow Copy Provider service.
Finally, to be absolutely sure that a successful snapshot can be made, you can run the following utility from command line:
C:\Program Files\Backup Manager\ClientTool.exe vss.exchange.check
If the result says the snapshot is created successfully, then the backup of Exchange will run fine.
Please note that in a future release, we hope to be able to indicate in the Dashboard if there are any problems with the VSS writer(s) that could cause an Exchange Backup to fail.
Potential causes of failure
If the initial backup takes longer than 24 hours to complete, the backup scheduled for the following day will be skipped with the message "Running a second simultaneous backup of VSS-based plugin is not allowed". This will show as "NotStarted" in the Dashboard.
There are several reasons that could lead to the loss of a snapshot, including a reboot of the server or a restart of the following services:
- Backup Service Controller
- Microsoft Exchange Information Store
- Volume Shadow Copy
- Microsoft Software Shadow Copy Provider
Should you have a failed backup session due to one of the above reasons, then afterwards please verify that the writer is stable by running the following command from the command line:
vssadmin list writers
Circular logging should be turned off. It will not affect the progress of the backup if it is turned on, but it can affect the integrity of the snapshot.
Databases are not mounted
Please ensure the selected Exchange databases are mounted before attempting to run the backup.
At the end of each session, Backup & Recovery informs Exchange if a snapshot of a store was successfully created. If this is the case, then Exchange itself will automatically purge transaction logs and so transaction logs are only truncated after a successful session. Exchange will not delete the logs (and the session will be unsuccessful) if Exchange determines inconsistency in the store or the logs. The integrity of Exchange can be checked using theEseutil.exe from Microsoft.
We know of one case where the server hanged during snapshot creation and a reboot was needed. The cause was the underlying HP hardware and was resolved by the following Microsoft update.
Cannot select Exchange Stores
In one or two isolated cases, some customers have reported a problem selecting the Exchange stores in Backup & Recovery as when clicking on Exchange, no tree is expanded.
The solution to this problem is to start regedit and find the following value:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem\Disable Exchange Writer
The data for that value should be set to '0'. Once done, restart both the Microsoft Exchange Information Store and Backup Service Controller services.
It should now be possible to select the Exchange stores in Backup & Recovery by clicking on Exchange to expand the tree.
Important: in line with best practice we suggest backing up the Windows registry before making any changes, as alterations to the Windows registry are immediately applied with no automatic backup.
For your consideration we have included Microsoft's warning on using their Registry Editor below:
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
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