"Backup failed because Azure Backup was unable to create a snapshot for the selected backup volume(s) due to insufficient space."

TH 101 Reputation points
2021-11-11T09:36:26.493+00:00

Hi all,

Got a Windows 2012R2 Server (Physical machine) which has been happily backing up to a vault in Azure for a year or more. Back up is for the C: drive which is 500GB. Usually has around 50GB free space, yesterday the free space had dropped to 30GB and the backup job failed with:

"Backup failed because Azure Backup was unable to create a snapshot for the selected backup volume(s) due to insufficient space."

30GB seemed a pretty healthy amount of free space but thought this may have been the cause so I freed up another 60GB of space to take the total free space to 90GB. Yet it's still failing. The error is thus:

Severity
Critical

Alert
Backup failure

Backup item(s)
C:\ on MyServer.

Description
Backup failed because Azure Backup was unable to create a snapshot for the selected backup volume(s) due to insufficient space.

Recommended action(s)
Make sure that at least 1 GB of free space is available in each of the backed up volumes.

Time
November 11, 2021 9:22 UTC

Vault
MyVault

Given the volume in question (which i understand to be C:) has an awful lot more free space than 1GB, I'm at a bit of a loss to understand what the problem is here.

Can anyone suggest what i need to do to resolve this issue?

Thanks in advance

Azure Backup
Azure Backup
An Azure backup service that provides built-in management at scale.
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Accepted answer
  1. TH 101 Reputation points
    2021-11-22T11:12:09.337+00:00

    After some back and forth with the Azure Microsoft tech support people, the solution which fixed the issue was as follows:

    1. In Windows explorer, right click on the volume (in this case the C: drive), select “Configure Shadow Copies…”
    2. Select the C:\ volume and click on settings and set to “No limit”.
    3. Restart the Volume Shadow Copy service.

    Then i left the auto backup job to run in MARS and it worked a-ok overnight.

    Hope this is of some help to someone.


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