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Application-consistent checkpoints for VHD set

    Question

  • Hi, everyone. I am trying to implement backup of Hyper-V guest cluster on Windows server 2016. Guest cluster nodes are windows server 2016 virtual machines with VHD set as a shared storage. Based on the description from TechNet, it is possible to include such disks into application-consistent checkpoints:

    VHD Set files are a new shared Virtual Disk model for guest clusters in Windows Server 2016. VHD Set files support online resizing of shared virtual disks, support Hype-V Replica, and can be included in application-consistent checkpoints.

    I am trying to call the CreateSnapshot method of the Msvm_CollectionSnapshotService, passing instance of 
    Msvm_VirtualSystemCollection with guest cluster virtual machines as members, but it fails with an error:

    'Win2016-node2' could not create auto virtual hard disk: General access denied error (0x80070005). (Virtual machine ID ADC556DC-427B-4F67-A128-D14F4F782C2A)

    All virtual machines files are located on CSV, including VHD set files. I found that similar issues occur if a virtual hard disk is located in root folder of CSV, but that's not my scenario, all files are located in non-root folders. 

    I granted NT VIRTUAL MACHINE\ADC556DC-427B-4F67-A128-D14F4F782C2A and second guest cluster VM full control permissions, but the problem still occurs.

    Can anyone guess, what is the reason of this error? I would appreciate any thoughts and ideas.


    Wednesday, February 08, 2017 9:52 AM

All replies

  • Hi Vadym,

    If you create a snapshot manually, is it successful?

    I suppose what you are doing is related to coding, and it seems I could not find related information about the error.

    You may also try to post in MSDN forum for help.

    Best Regards,

    Leo


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    Thursday, February 09, 2017 5:22 AM
    Moderator
  • Hi Leo,

    Checkpoint creation from Failover Cluster Manager GUI fails with error:

    "Cannot take checkpoint for 'Win2016-node2' because one or more shareable VHDX are attached and this is not part of a checkpoint collection."

    Can you recommend where exactly on MSDN forum it is better to post such question? Yes, it's related to coding, but it's even more related to Hyper-V.

    Friday, February 10, 2017 9:35 AM
  • Hi Vadym,

    The only related information I could find about is stating it as supported, nothing about the error.

    I would post here if I got any updates on it.

    Best Regards,

    Leo


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

    Monday, February 13, 2017 7:06 AM
    Moderator
  • Same issue here: https://social.technet.microsoft.com/Forums/windowsserver/en-US/0d6cddde-3ff3-4a50-a627-6ad7bf7667fd/cannot-create-checkpoint-when-shared-vhdset-vhds-is-used-by-vm-not-part-of-a-checkpoint?forum=winserverClustering

    And also we have the same issue. Need to find a solution quickly.

    Kind regards

    Michael

    Monday, February 13, 2017 8:26 AM
  • Hi there,

    Yes, while working with shared disks I also got 'General access denied' unexpected errors. However I haven't got the reason, the problem was transient.

    I suggest to collect tcpdump of the traffic between RSVD client (HyperV) and RSVD server (SOFS) and to check what particuar step is failing. I know that CreateSnapshot flow includes several stages, maybe server replies failure somewhere in the middle.

    Monday, February 13, 2017 11:13 AM
  • Hi Volodymyr,

    Thanks for sharing your experience, it's good to know that someone also faced the same problem. I already tried to track vmms.exe process activity during CreateSnapshot call with Process Monitor from Sysinternals, but I haven't found any "Acess denied" errors. But I'll try to collect tcpdump, maybe it will help to figure out what's the problem.

    Monday, February 13, 2017 12:09 PM
  • Hi there,

    do you have KB3213986 installed on the Host System? This is what is causing the error on my end. Uninstalling leads to a BSOD, so I have no solution to that yet. Kind of waiting for a patch here without knowing what the exact reason is (Best guess would be a code issue with vmms.exe).

    Have you solved your problem in the meantime?

    Monday, April 10, 2017 6:31 AM