Article ID: 2549533 - View products that this article applies to.
When using System Center Data Protection Manager (DPM) 2010 to perform host level backup of guests located on a CSV in Windows 2008 Hyper-V Cluster, some recovery point jobs fail intermittently with one or more of the following errors:
Type: Recovery point
This usually occurs if the Cluster nodes hosting the Cluster Shared Volume (CSV) storage do not have a Volume Shadow Copy Service (VSS) Hardware snapshot provider installed. When no VSS hardware snapshot provider is installed, you must enable both Cluster and CSV Serialization as documented in the following TechNet article.
To see what VSS Snapshot providers are installed on the system, run VSSADMIN LIST PROVIDERS from an administrative command prompt. The default in-box system software provider is listed as follows. Note the Provider ID GUID is the same across Windows operating system versions.
Provider name: 'Microsoft Software Shadow Copy provider 1.0'
However, even when using a VSS hardware snapshot provider, the error may still occur if you have a single CSV hosting all your Guests.
If serialization is enabled and you have a special character like an & in your Hyper-V virtual machine guest name, that will cause the %programfiles%\Microsoft DPM\DPM\Config\DataSourceGroups.xml file not to be parsed properly and the serialization will not work even when configured properly.
If you believe you have serialization enabled properly, check the %programfiles%\Microsoft DPM\DPM\Config\DataSourceGroups.xml file on the DPM server for special characters like & character. The easiest way to accomplish that is to open the DataSourceGroups.xml file using Internet Explorer - there should be no errors.
Regardless if using hardware or software snapshot provider , the following registry settings allow you to make adjustments to how DPM performs retries to claim the CSV in order to get reliable backups.
CsvMaxRetryAttempt - Adjust the maximum number of times (Default is 1) the DPM agent will attempt to claim the CSV volume. The value 0xC8 = 200 times.
1) Copy the following in notepad, then save the file as csvretry.reg
Windows Registry Editor Version 5.00
2) Copy the csvretry.reg file to each node in the cluster.
3) Logon to each node in the cluster as an administrator, then right-click the csvretry.reg file and select "open with" - then "Registry Editor" option to import the registry settings.
NOTE: Should you continue to see the 0x8007173D errors, investigate further using this procedure:
1) Collect the %Programfiles%\Microsoft Data Protection Manager\DPM\Temp\DPMRACURR.ERRLOG from each node of the cluster.
Findstr /S "vsssnapshotrequestor.cpp(170) vsssnapshotrequestor.cpp(390) vsssnapshotrequestor.cpp(424) csvapi.cpp(400) vsssnapshotrequestor.cpp(585) hypervwriterhelperplugin.cpp(960) datasetfixupsubtaskbase.cpp(227) vsssnapshotrequestor.cpp(1111) freesnapshotsubtask.cpp(671)" *DPMRA*.errlog >ALL-BACKUP-START-FINISH.TXT
Open the ALL-BACKUP-START-FINISH.TXT text file in notepad and remove any entries not within the time period of the hyper-v backup times. You can see the order of the backups and the CSV retry attempts.
EXAMPLE OF GOOD HYPER-V GUEST BACKUP LOG ENTRY - Note that the ProviderID in this case is the Microsoft Software VSS Provider.
EXAMPLE OF FAILED BACKUP EVEN AFTER 4 RETRIES CsvMaxRetryAttempt = 3 and CsvAttemptWaitTime = 3 minutes
Should the Host level backups fail intermittently for other reasons, by default DPM will auto-retry the backup one hour after the original failure. Should that backup also fail, no additional retries are attempted.
To change the default auto-retry interval and count, you can adjust the following registry settings. Note: These will effect ALL DPM jobs, not just Hyper-V Guest backup jobs.
AutoRerunDelay - The delay in time in minutes before which DPM will attempt to automatically rerun failed jobs. If multiple reruns are configured, this is the gap between the reruns as well. The value of 0x3c = 60 minutes.
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Data Protection Manager\Configuration]
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Article ID: 2549533 - Last Review: September 12, 2011 - Revision: 8.0