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Hyper-V not merging snapshots automatically - Disk merge failed. RRS feed

  • Question

  • Hi,

    I have asked this question before however the same problem has occurred and is driving me crazy. Now we have a 2016 Hyper-V environment with Server 2016 VMs. We run daily backups using DPM 2016.

    Now I came in after the weekend to find that all of my VM backups had failed and every VM that had failed had a .avhdx file left behind. I have tried shutting down the virtual machine but I get caught out with "Merge in Progress - Failed".

    Sometimes when I shutdown the virtual machine it will fail to start and say that there is an issue with the virtual hard disk chain and it needs to be reconnected.

    The only way I have found to fix it is to manually merge the virtual hard disks and then re-create the virtual machine. This works and then I can take another backup however a few days later the same issue will happen again.

    I don't have time to constantly merge virtual machines every other day and of course it affects the production environment. There have been changes to our group policy and as it is affecting all of our hosts I wonder if this is the problem however I am not sure what to look at. I heard about the "Logon as a service" causing an issue however this made no change for me.

    If anyone has any ideas I would love to hear them, currently going through it with Microsoft Support however they don't listen to the issue.

    Tuesday, October 8, 2019 9:39 AM

Answers

  • Hi Daniel,

    Sorry for not getting back to you!

    I have actually found out the issue myself (which is awesome as this has been happening for a little while) it turns out it was related to group policy and the way that "Logon as a service" had been setup. Basically both NT VIRTUAL MACHINE\Virtual Machines & NT SERVICES\ALL SERVICES was missing from that particular GPO meaning that we were having all kinds of issues with backups, Hyper-V management etc.

    So after modifying group policy and adding those back in, GPUPDATE /FORCE on all hosts and merging is now happening as normal.

    The main test will be tomorrow morning to see if I have any lingering snapshots from tonights backup but yes, problems solved!

    • Marked as answer by Kyle Moody Monday, October 14, 2019 3:19 PM
    Monday, October 14, 2019 3:19 PM

All replies

  • Hi,

    Thanks for posting in our forum!

    >>Now I came in after the weekend to find that all of my VM backups had failed and every VM that had failed had a .avhdx file left behind. 

    Is there any related error message in Event Viewer?

    >>The only way I have found to fix it is to manually merge the virtual hard disks and then re-create the virtual machine. 

    I think what we need to do at present is to discuss with DPM experts how to solve the problem of virtual machine backup failure.Let's focus on this issue first with DPM experts.

    In addition, i mentioned that you have already open a case to MS support, but they don't listen to your issue.

    I believe that Microsoft supporters will contact you soon and work with you to solve this problem. If you have any progress and feedback, you are welcome to come back and share with us at any time!

    At present, we need to wait for the voice from DPM forum and MS Support.

    Really appreciated your understanding!

    Best Regards,

    Daniel


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Wednesday, October 9, 2019 7:53 AM
    Moderator
  • Hi,
    Just want to confirm the current situations.
    Please feel free to let us know if you need further assistance.
    Best Regards,
    Daniel

    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Friday, October 11, 2019 8:12 AM
    Moderator
  • Hi,
    This is Daniel and wish you all the best!
    As this thread has been quiet for a while, we will mark it as ‘ Propose answered’ as the information provided should be helpful. If you need further help, please feel free to reply this post directly so we will be notified to follow it up. You can also choose to unmark the propose answer as you wish.
    BTW, we’d love to hear your feedback about the solution. By sharing your experience you can help other community members facing similar problems. Thanks for your understanding and efforts.
    Best Regards,
    Daniel

    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, October 14, 2019 2:23 AM
    Moderator
  • Hi Daniel,

    Sorry for not getting back to you!

    I have actually found out the issue myself (which is awesome as this has been happening for a little while) it turns out it was related to group policy and the way that "Logon as a service" had been setup. Basically both NT VIRTUAL MACHINE\Virtual Machines & NT SERVICES\ALL SERVICES was missing from that particular GPO meaning that we were having all kinds of issues with backups, Hyper-V management etc.

    So after modifying group policy and adding those back in, GPUPDATE /FORCE on all hosts and merging is now happening as normal.

    The main test will be tomorrow morning to see if I have any lingering snapshots from tonights backup but yes, problems solved!

    • Marked as answer by Kyle Moody Monday, October 14, 2019 3:19 PM
    Monday, October 14, 2019 3:19 PM
  • Ok,thanks for your sharing!


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Tuesday, October 15, 2019 1:16 AM
    Moderator