NetWorker: Troubleshooting Backup Failures Due to VSS Issues

Backups of a Windows client are failing due to VSS issues. There are several different reasons that could result in VSS failing to process a snapshot on the client operating system; for example: Unstable VSS writer, or insufficient space to create a snapshot.

These issues are typically indicated in the backup logs which can be observed in the NMC.

VSS OTHER: ERROR: VSS failed to process snapshot: 
90108:save: Unable to save the SYSTEM STATE save sets: cannot create the snapshot. 

7259:save: VSS reports adding volume [C:\] <file:///C:/]> to snapshot set failed for both hardware/software provider.VSS OTHER: ERROR: VSS failed to process snapshot: Unexpected VSS provider error.

VSS OTHER: ERROR: VSS failed to process snapshot: Insufficient storage available to create either the shadow copy storage file or other shadow copy data. (VSS error 0x8004231f)
90108:save: Unable to save the SYSTEM STATE save sets: cannot create the snapshot.

VSS-related events are also visible in the Windows Event Viewer on the client.

First rule out a potential capacity issue. Microsoft recommends leaving 10-15% of a drives total capacity available for completing VSS snapshots. If the capacity is above 90%, VSS snapshots may fail.

To test whether or not VSS is working correctly on the client operating system, run the following commands from an administrative command prompt:
1. Check the VSS writers status: vssadmin list writers
Example:

c:\>vssadmin list writers
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2012 Microsoft Corp.

Writer name: 'System Writer'
Writer Id: {e8132975-6f93-4464-a53e-1050253ae220}
Writer Instance Id: {34a07e16-fcdb-4ab0-b603-d58c0f741c9a}
State: [1] Stable
Last error: No error
...
...

2. If the writers are stable check for preexisting snapshots, there should be none: vssadmin list shadows
Example:

c:\>vssadmin list shadows
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2012 Microsoft Corp.

No items found that satisfy the query.

c:\>vssadmin delete shadows /all
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2012 Microsoft Corp.

Do you really want to delete 1 shadow copies (Y/N): [N]? y

Successfully deleted 1 shadow copies.

c:\>vssadmin create shadow /for=C:\
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2012 Microsoft Corp.

Successfully created shadow copy for 'C:\'
    Shadow Copy ID: {1f6a1448-daad-4e68-a334-31dd40a64dd9}
    Shadow Copy Volume Name: \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy2

5. If you successfully created a snapshot, delete it using the command from step 3 and run a backup of this client. If the backup fails with a VSS issue, contact Dell NetWorker support for assistance. It is also recommended to engage Microsoft support in the event collaboration is needed between NetWorker support and Microsoft support. 

• VSS Space Requirements: https://technet.microsoft.com/en-us/library/cc161409.aspx
• VSS Snapshot Storage: NetWorker: File system Backup Failure "Insufficient storage available to create either the shadow copy storage file or other shadow copy data"
• VSS Information: https://msdn.microsoft.com/en-us/library/windows/desktop/aa384625(v=vs.85).aspx
• More advanced VSS troubleshooting steps are documented in: VSS Tracing and Troubleshooting Options

Workaround:

The following workaround can be used to obtain successful backups without VSS.

1. Log in to the NetWorker Management Console (NMC).
2. Ensure View->Diagnostic Mode is enabled in the NMC.
3. Access the Windows client's properties from the Protection->Clients tab.
4. In the General tab of the client properties, change the Save sets field to only include volume, folder, or file names (For example: C:\).

5. In the Apps & Modules tab, set vss:*=off under Save operations.
6. Perform a backup of the client.
7. Once the VSS issues are resolved, remove the vss:*=off setting and set the client's save set field to All, or include the DISASTER_RECOVERY:\ save set to obtain system state.