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Restore, live browse, or GUI mount of application-aware snapshots fail with error "VSS software snap not found"

Symptom

Restore, live browse, or GUI mount of application snapshots on Windows hosts might fail. The following error appears in the Job Pending Reason (JPR) and the CVMA.log file.

VSS software snap not found

Application snapshots are contained in the VSA hardware snapshot that is created by an application-aware backup job.

Cause

This issue can occur in the following cases:

  • Volumes on the disks from the VSA backup that are attached to the mount host during the application snapshot mount do not come online automatically.
  • The VSS software snapshot is not found because VSS marked it as a stale entry.

Resolution

  1. Perform the restore, live browse, or GUI mount of application snapshots.

    For a restore, specify the VSA proxy with the Use Proxy option on the Data Path tab of the Advanced Restore Options dialog box.

  2. If the operation still fails, perform these additional steps:
    1. On the mount host, VSA proxy, or source VM where the application snapshot is being mounted, enable automount by running the following command from the Windows command prompt:

      diskpart> automount enable

      By default, the snapshot is mounted on the destination application client for the restore.

    2. The shadow storage for a VSS snapshot of an application volume must be associated to the same volume as the volume being snapped.

      Use the vssadmin add shadowstorage command to set the shadow storage association for a volume on guest VMs. The following example for an application that resides on volume D: specifies that volume D: is to be used for storage and that the maximum size for storage space should be 900 MB:

      vssadmin add shadowstorage /for=D: /on=d: /maxsize=900mb

    3. Retry the operation.
  3. For IntelliSnap application-aware backups of VMware VMs, if the operation still fails, configure the nRevertShadowsBeforeMount additional setting on the mount host (for example, the VSA proxy or the destination application client), as shown in the following table.

    For instructions on adding additional settings from the CommCell Console, see Adding or Modifying Additional Settings from the CommCell Console.

    Property

    Value

    Name

    nRevertShadowsBeforeMount

    Category

    iDataAgent\VSA_APP_AWARE

    Type

    Integer

    Value

    1

    This additional setting reverts the VSS shadows on the VM that is temporarily mounted from the VSA hardware snap, instead of trying to mount the VSS shadow.

  4. If the operation still fails, perform these additional steps:
    1. Perform an out-of-place restore of the full VM.
    2. On the restored VM, manually revert VSS shadows on all of the VM disks:

      Run the following commands from the command prompt and identify the list of shadow copy IDs for each disk using the creation timestamp:

      diskshadow
      list shadows all

      Run the following command for each shadow copy ID:

      revert shadow_copy_id

    3. Manually restore data from the restored VM to the destination VM using the database dump files.
  5. For future application-aware backups, consider one of the following solutions:
    • To use application-consistent snapshots instead of VSS shadows for application-aware backups of VMware or Hyper-V VMs, add the nEnableHypervisorAppConsistentBackup additional setting to the VSA proxy and the application client computer, as shown in the following table.

      For instructions about adding an additional setting from the CommCell Console, see Adding or Modifying Additional Settings from the CommCell Console.

      Property

      Value

      Name

      nEnableHypervisorAppConsistentBackup

      Category

      VirtualServer

      Type

      Integer

      Value

      1

    • Instead of performing application-aware backups, deploy an in-guest agent for backups of application data.

      Note: If you configure the nEnableHypervisorAppConsistentBackup additional setting, so that backups use application-consistent hypervisor snapshots instead of VSS shadows, application-aware backups are not supported for applications that use nested mount points for application configuration. As a workaround, you can reconfigure the application to use different drive letters for each file location, or install an application agent on the virtual machine and use that agent to perform backups.

Last modified: 5/21/2020 9:17:17 PM