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Thread: Backup failed because a hot backup could not be performed for the selected guest VMs

  1. #1
    Join Date
    Mar 2014
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    4

    Default Backup failed because a hot backup could not be performed for the selected guest VMs

    I am running ZCB on a Windows Server 2012 R2 machine that hosts four Hyper-V VMs. One VM is running Windows Server 2012 R2, two are running Windows Server 2008 R2, and one is running Windows 8. So far, I have not been successful in getting any VMs to back up.

    After consulting the user guide, I discovered my issue was dynamic disks - all of my VMs were configured with dynamic disks, thus ZCB could not perform a hot backup. To test, I have converted one of the Windows Server 2008 R2 VMs to a fixed disk. I have also been careful to follow the "Child VM Snapshot" method requirements:

    •Backup (volume snapshot) Integration Service is installed and running in the child VM. The service name is "Hyper-V Volume Shadow Copy Requestor".
    - Verified.

    •The child VM must be in the running state.
    - Verified.

    •The Snapshot File Location for the VM is set to be the same volume in the host operating system as the VHD files for the VM.
    - On the host machine (Windows Server 2012 R2, Hyper-V Manager 6.3.9600.16384), research indicates that "Snapshot File Location" is now called "Checkpoint File Location." Assuming this is correct, then this requirement is verified by the following:

    Virtual Hard Disk File Path:
    V:\VMs\GIS01\GIS01.vhd

    Checkpoint File Location:
    V:\VMs\GIS01

    •All volumes in the child VM are basic disks and there are no dynamic disks.
    - Only one disk in the VM, and I converted it to basic myself.

    •All disks in the child VM must use a file system that supports snapshots (for example, NTFS).
    - Verified.

    At this point, I have run out of options to investigate, bringing me here. My only other option is to use the "Saved State" method of backing up VMs, which will require setting up scripts to trigger the PreSnapshot and PostSnapshot events, during which the VM will be unavailable. If at all possible, I'd like to avoid this.

    Please let me know if there is anything else I can do to get hot backups of Hyper-V VMs working with ZCB.

    Thank you!

  2. #2
    Join Date
    Jan 2012
    Location
    Oklahoma
    Posts
    128

    Default

    Hello,

    I've seen this happen before when there's a problem with the disks themselves. I recently assisted someone who had issues with his RAID array, which was causing his hyper-v backups to fail out even though all other requirements were met.

    Is there anything indicating disk trouble in your System or Application Events?

    Also, Windows Server 2012 R2 is not yet officially supported by ZCB, just regular Windows Server 2012. Same story with Windows 8 (supported) vs 8.1 (not yet). I expect most functions will work, but there will be gaps in functionality since the released version of ZCB was not tested against 2012 R2. I know there are problems with System State restores in 2012 R2 for sure. These problems will be fixed when official support for 2012 begins.

    Official support for Server 2012 R2 will be available when ZCB version 4.10 is released. Estimated release is early Q2, possibly as soon as early April. No firm date has yet been set.

    If there are not obvious issues from your Events, would you be so kind as to open a support ticket and provide DEBUG logs? We should be able to tell if this is a OS compatibility issue or of it's something else.

    [url]http://help.zmanda.com/display/KB/Collecting+ZCB+logs+for+troubleshooting[/url]

  3. #3
    Join Date
    Mar 2014
    Posts
    4

    Default

    Eric,

    Thanks for the quick response. Though I am not an expert, there are no events that would indicate to me any issue with the RAID array. The server itself is over two years old, but all hard drives that are part of the array were purchased new and have been in service for less than two months.

    To that end, I have gone ahead and created a support case (#14634) and uploaded logs through the ZCB UI. Either via the support case or via this forum, please let me know if the answer does turn out to be Windows Server 2012 R2 compatibility issues. If so, I will be content to wait for the ZCB update in Q2. Otherwise, I'll be happy to try any other options or troubleshooting to solve the issue.

  4. #4
    Join Date
    Jan 2012
    Location
    Oklahoma
    Posts
    128

    Default

    I've responded to your ticket. Thanks for opening it!

    Let's you or I put the results here once we figure this out.

  5. #5
    Join Date
    Jan 2012
    Location
    Oklahoma
    Posts
    128

    Default

    Thanks for your time troubleshooting the VSS issues we found. It turned out to be a red herring, but it was worth checking into.

    In the end, it looks like this is indeed a compatibility issue with Server 2012 R2, which uses a completely different namespace than 2012 and earlier.

    Some discussion on the topic can be found here:
    [url]http://social.technet.microsoft.com/Forums/windowsserver/en-US/2e136429-48b2-4f5b-9fc9-f41a6f8ae8a6/cant-query-vms-file-using-rootvirtualization-wmi-namespace-in-windows-2012-r2?forum=winserverhyperv[/url]

    This will be resolved in ZCB 4.10, which will more than likely be available in early April.

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