Data Protector backup job throws “Fallback to legacy filesystem backup was not allowed”

Wheb backing-up a Windows Client, sometimes the error “Fallback to legacy filesystem backup was not allowed” occurs. In most cases this is related to the CONFIGURATION object, but recently I noticed this also on the D-drive of a (SQL) server.

[Critical] From: VBDA@client “fqdnoftheclient [/D]” Time: 3/25/2014 8:16:09 AM
Fallback to legacy filesystem backup was not allowed. Aborting the backup.
[Critical] From: VBDA@client “fqdnoftheclient [/D]” Time: 3/25/2014 8:16:09 AM
[81:52] /D Not a valid mount point => aborting.

The software tries to start a backup by using the VSS integration and when this fails it fallbacks to the legacy method. If this is not defined in the backupjob properties, the backupjob will fail with the error mentioned above.


First of all, we need to find out why the VSS-backup is not successful. In the eventviewer application log we can find the following error: “Volume Shadow Copy Service error: Error calling a routine on the Shadow Copy Provider {b5946137-7b9f-4925-af80-51abd60b20d5}. Routine returned E_INVALIDARG. Routine details GetSnapshot({00000000-0000-0000-0000-000000000000},00000000001C51A0).

In first case, I always check the VSS providers and VSS writers on the client itself by executing the following commands in an elevated command prompt:

  • vssadmin list writers to verify if no error are listed and the state is stable;
  • vssadmin list providers to verify if no other VSS providers are installed (cfr. Backup Exec VSS provider).

To resolve any errors listed when executing the vssadmin list writers command, the simplest way is to reboot the server.

Once done, you can try to create a manual VSS Snapshot  by executing the following command: vssadmin create shadow /for=D: where D: refers to the error indicated in the Data Protector sessionlog.

C:\Users\account>vssadmin create shadow /for=D:
Successfully created shadow copy for ‘D:\’
Shadow Copy ID: {4f9b2ac8-3f6e-4b29-bc54-4eb279d6df2b}
Shadow Copy Volume Name: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy35

C:\Users\account>vssadmin list shadows
Contents of shadow copy set ID: {40ade498-839f-4319-a58b-cb31fef411ec}
Contained 1 shadow copies at creation time: 4/3/2014 2:14:26 PM
Shadow Copy ID: {4f9b2ac8-3f6e-4b29-bc54-4eb279d6df2b}
Original Volume: (D:)\\?\Volume{1cc4e834-edda-11e2-b05e-0050568c19bd}\
Shadow Copy Volume: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy35
Originating Machine: ELCSQL7A.EPS.Local
Service Machine: ELCSQL7A.EPS.Local
Provider: ‘Microsoft Software Shadow Copy provider 1.0′
Type: ClientAccessible
Attributes: Persistent, Client-accessible, No auto release, No writers,
Differential

If you want to delete the freshly create snapshot, this can be performed by executing the following command: vssadmin delete shadows /For=D: /Oldest.

As a best practice I activate the following options in my backup job configuration by default:

  • Options > WinFS Options > MS Volume Shadow Copy Options > Allow fallback = YES.
  • Backup Object Summary > clientname > Properties > WinFS Options > MS Volume Shadow Copy Options > Allow fallback = YES.

Afterwards the issue should be resolved.

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