Hyper-V backup fails with Error creating VSS snapshot (4037858)

Hyper-V backup fails with Error creating VSS snapshot

In the binary log we see the following entries:

Error      2015/02/25 11:54:24      70           Data Plugin         HOST01               Error creating VSS snapshot

Error      2015/02/25 11:54:24      70           Data Plugin         HOST01               Failed to backup VM VMOPENERP

Error      2015/02/25 12:14:27      70           Data Plugin         HOST01               Error creating VSS snapshot

Error      2015/02/25 12:14:27      70           Data Plugin         HOST01               Failed to backup VM VMDC03

Below are 2 possible causes of this problem that may help resolve the problem:

1/ this problem can be caused by The 'Maximum Shadow Copy Storage space' limitation on the space that can be used when creating VSS shadowcopies might be too small for creation of the shadowcopy.

Use the command below to verify that the 'Maximum Shadow Copy Storage space' isn't too small:

        vssadmin List ShadowStorage

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Below is sample output showing that 17 GB of 20 GB maximum space is being used by VSS shadowcopies on a volume, we would recommend that the maximum size value be increased.

        Used Shadow Copy Storage space: 17.053 GB (22%)

        Allocated Shadow Copy Storage space: 18.02 GB (24%)

        Maximum Shadow Copy Storage space: 20 GB (26%)

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Resolution

If the OS's current Shadow Copy settings seem to be too small, that limit can be increased by using the following Windows command:

        vssadmin Resize ShadowStorage

Example:

vssadmin resize shadowstorage /For=D: /On=D: /MaxSize=50GB

In order to do the resize, please follow Microsoft's recommendations on the following Microsoft TechNet KB article:

        http://technet.microsoft.com/en-us/library/cc788050.aspx

Note:  This issue is strictly a Windows issue and in no way NetVault-related.

2/ netvault uses the 'Microsoft Software Shadow Copy provider 1.0' abd if we have other providers they can be used and cause the backup failure in this way. To check providers use the following command.

vssadmin list providers

below we see that there are two providers and the 'Microsoft File Share Shadow Copy provider' will need to be removed.

Provider name: 'Microsoft File Share Shadow Copy provider'

   Provider type: Fileshare

   Provider Id: {89300202-3cec-4981-9171-19f59559e0f2}

   Version: 1.0.0.1

Provider name: 'Microsoft Software Shadow Copy provider 1.0'

   Provider type: System

   Provider Id: {b5946137-7b9f-4925-af80-51abd60b20d5}

   Version: 1.0.0.7

you will need to schedule following changes to configure the  vss provider for the hyper-v host.

Does the following registry key for the "Microsoft File Share Shadow Copy provider" exist?

      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VSS\Providers\{89300202-3cec-4981-9171-19f59559e0f2}

If so, removal of that registry key, then rebooting should remove that secondary VSS hardware provider from the system, which should also remove the conflict when trying to pull the VSS shadowcopy from the default Windows VSS hardware provider.

Aways take  a backup of the registry** (export to a .REG file) from the Hyper-V host before removing the "Microsoft File Share Shadow Copy provider" .

Remove  "Microsoft File Share Shadow Copy provider"

      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VSS\Providers\{89300202-3cec-4981-9171-19f59559e0f2}

Then reboot the Hyper-V host and check if issue still exists.

Note if you have any other provider than 'Microsoft Software Shadow Copy provider 1.0' you will need to remove these providers as well.