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Backup Failing of Hyper-V VM

Thread needs solution
Beginner
Posts: 7
Comments: 15

Hi,

I'm running Hyper-V on a 2012 R2 Host with currently just a single 2012 R2 Guest VM.
I'm on the latest version of Acronis 11.5.37884 installed on the Host

I have a backup job which I am running manually which is backing up the Guest VM. This was all working fine initially for a couple of weeks.
This is a test server and so I was taking backups of the guest as and when I made changes to the guest VM. Which has basically just been a test server to plan for an SBS 2008 to 2012 R2 migration

Then suddenly and I'm not entirely sure when exactly the backups started to fail with the error below.
I've done a full uninstall, cleanup, re-install of Acronis, new backup job and it still fails.
On the host I have a C:\ partition which has 90GB free out of 127GB and a D:\ partition which has 655GB free from 1.51TB
Guest VM currently only has a 149GB C: partition with 138B free
Backups fail with or without VSS enabled and shadow copy has been enabled and configured on both host and guest.

The error I get is....

Failed to start creating the volume snapshot.
Additional info:
--------------------
Error code: 50242
Module: 16
LineInfo: 14181c22ef45b0ed
Fields: $module : hv_srv_vs_38774
Message: Failed to start creating the volume snapshot.
--------------------
Error code: 50281
Module: 16
LineInfo: 14181c22ef45aa24
Fields: $module : hv_srv_vs_38774
Message: VSS writer 'Microsoft Hyper-V VSS Writer' with class ID '66841CD4-6DED-4F4B-8F17-FD23F8DDC3DE' has failed to process the snapshot.
--------------------
Error code: 65520
Module: 0
LineInfo: bd28fdbd64edb8f8
Fields: code : 2147754995, $module : hv_srv_vs_38774
Message: Unknown Win32 error
--------------------

Event Logs show errors
8229 - A VSS writer has rejected an event with error 0x800423f3
8220 - Ran out of time while deleting files. I thought this may just be a time-out error so I increased the VSS timeout on the host to 30mins but still fails.

VSSAdmin List Writers Shows....
Hyper-V VSS Writer in 'Retryable Error'
Error State 8 - Failed

Would really appreciate any help!

Thanks, David

0 Users found this helpful
Acronis Program Manager
Posts: 22
Comments: 3120

Hi David,

The root cause here is in the failing Hyper-V VSS writer and there should be some more errors in the event logs which would give more clues. In the following thread installation of latest MS updates fixed the same problem: https://forum.acronis.com/forum/45420 . From other sources I see that rebooting the entire Hyper-V host helps to reset the VSS writer state and bring it to normal.

If the above doesn't help and digging further into event logs doesn't give more clues, then I'd recommend contacting our support team for assistance (probably involvement of Microsoft support will also be required) with the logs + event logs from Hyper-V host and the guest VM.

Thank you.
--
Best regards,
Vasily
Acronis Virtualization Program Manager

Beginner
Posts: 7
Comments: 15

Hi,

Thanks for the response.

I already have update KB2883200 and the host has been rebooted lots.

I don't have a current valid support agreement as we are testing Acronis on Hyper-V using an NFR key. Obviously once we're happy that it works ok, we'll be buying it for all our new virtualized servers running Hyper-V as we do for all our 75 or so physical servers we have.

I might just flatten the host and start from scratch and try and monitor when and if it goes wrong again to try pin point the change made on the Host/VM that causes this issue. As I said it was working perfectly fine for 2 weeks and that was without any configuration. I just installed Acronis and created a backup job and it worked. Didn't even configure shadow copies, etc at that point.

The only thing that changed was the VM went from a workgroup Server 2012 R2 to being on a domain and then promoted to single DC, removing existing SBS server from the domain.

Thanks, David

Acronis Program Manager
Posts: 22
Comments: 3120

Hi David,

It could be that the VSS writer indeed broke after DC join or DC promotion. Given that this was the only event between normal backups and failures - I'd troubleshooted the problem by trying to take native VSS backup (with Windows Backup -> back up system state) from inside the VM. Probably there are some permissions issues with the accounts used to run the VSS writers under. See also below thread which might be related:

http://social.technet.microsoft.com/forums/windowsserver/en-US/29f1543a-3481-481f-8f1e-c79332959d24/vss-warning-after-domain-controller-promotion

Thank you.
--
Best regards,
Vasily
Acronis Virtualization Program Manager