DPM 2012 R2 recovery issue of Hyper-V virtual machines RRS feed

  • Question

  • Hello,

    When we try to list the items in a protected VHDX files we receive the following error:

    DPM cannot browse the contents of the virtual machine on the protected computer dpm01.fabrika.local. Item level recovery is not supported in the following scenarios.
    1. The VHD contains a dynamic disk inside the guest OS.
    2. The VHD has no volume.
    3. HyperV role is not installed on DPM server.
    4. Automatic mounting of volumes is disabled on the DPM server.

    1) Try enabling automatic mounting of volumes using mountvol on the DPM server to preform item level recovery.
    2) Otherwise perform a full restore of the virtual machine.

    ID: 958
    Details: Internal error code: 0x80990F4E

    Not all virtual machines experience this error. Machines that do experience the error sometimes can be recovered as a full VHDX file, but sometimes even that is not possible. Then it fails with the error on RaReadData function (I will post the exact error later).

    We are using Hyper-V 2012 R2 virtual machines, DPM 2012 R2 with UR8 that is also installed inside a virtual machine. Storage Pool VHDX files for DPM are located on a Hyper-V host volume that has deduplication enabled. We have followed the DPM deduplication white paper and have configured the environment as suggested but we don't have Scale-Out file server cluster. However, it should be supported because in the FAQ section of the whitepaper it is suggested that deduplication can also be configured without it:

    Q: It looks as though DPM storage VHDX files must be deployed on remote SMB file shares only. What will happen if I store the backup VHDX files on dedup-enabled volumes on the same system where the DPM virtual machine is running?

    A: As discussed above, DPM, Hyper-V and dedup are storage and compute intensive operations. Combining all three of them in a single system can lead to I/O and process intensive operations that could starve Hyper-V and its VMs. If you decide to experiment configuring DPM in a VM with the backup storage volumes on the same machine, you should monitor performance carefully to ensure that there is enough I/O bandwidth and compute capacity to maintain all three operations on the same machine.

    So far we have managed to reproduce the problem on two separate environments so it is not something related specifically to the environment but rather to the DPM itself. We have also noticed that the data is recoverable and readable before it is deduplicated but once the optimization process completes, we experience the issue for some VMs. Maybe it is to early to talk about data corruption but we are not able to recover the data.

    Any suggestions?

    Dinko Fabricni

    Sunday, November 29, 2015 8:13 AM