NetBackup™ for Hyper-V Administrator's Guide

The following notes and restrictions apply to NetBackup for Hyper-V:

• For VSS with disk arrays:

  To use a hardware array snapshot, make sure that the hardware array's VSS provider supports the snapshots that involve the Hyper-V writer. Consult the release notes of the array vendor or VSS provider.

• NetBackup for Hyper-V does not support the NetBackup Instant Recovery feature.

• The following is due to a Microsoft limitation: NetBackup for Hyper-V does not support VSS or WMI backup or restore of the vhdx files that are shared among multiple VMs.

• To perform Hyper-V backups with the SAN Client feature, install SAN Client on the Hyper-V server. Do not install SAN Client on the virtual machines. For more information on SAN Client with Hyper-V, see the NetBackup SAN Client and Fibre Transport Guide.

  Note:

  The SAN Client feature for Hyper-V is only supported for the VSS backup method (not for WMI).

• The following is due to a Microsoft limitation: If the VM's virtual disk files reside in a volume or folder that is compressed, NetBackup cannot use the WMI backup method to create a snapshot of the VM. The snapshot job fails with status 156, "snapshot error encountered."

  As a workaround, remove compression from the volume or folder where the virtual disk resides and rerun the backup.

• NetBackup for Hyper-V supports Windows NTFS file encryption and compression, for backup and restore. However, it does not support NetBackup's compression or encryption options (in the NetBackup policy attributes).

  For UNIX or Linux guest operating systems: NetBackup for Hyper-V does not support any type of compression or encryption, whether they are set in NetBackup or in the guest OS.

  Note:

  The compressed Windows NTFS files are backed up and restored as compressed files.

• If a policy is changed from manual selection to Intelligent policy (or vice versa), note: The next backup of the VM is a regular full backup, even if a backup already exists for that VM.

  For example:

  • In a new Hyper-V policy, the Select manually option on the Clients tab is used to select a VM. The first backup from the policy runs.

  • If the primary VM identifier is a host name, ensure that you configure Microsoft failover cluster with FQDN of VM getting protected.

  • In the policy, an Intelligent Policy query is used to select the same VM, and the VM is backed up a second time. Because of the switch from manual selection to query-based selection, this second backup is a regular full backup. Note that for a policy that uses Enable block-level incremental backup (BLIB) or BLIB plus Accelerator, the backup processing is not limited to changed blocks only.

    For the second backup, the Detailed status log includes a message similar to the following:

    Sep 29, 2016 11:16:53 AM - Info bpbrm (pid=13680) There is no 
    complete backup image match with track journal, a regular full 
    backup will be performed.

    The same backup behavior occurs if the policy's VM selection is switched from query-based to manual selection: The second backup is a regular full backup.

• For the WMI backup method with the Enable block-level incremental backup option (with or without Accelerator): If the VM has multiple virtual disks that have the same disk UUID, NetBackup performs a full backup of those disks. It does not perform an incremental backup of them. The disks that have unique IDs undergo an incremental backup, as expected. In the Activity Monitor, the job details include messages such as the following:

  The virtual machine (Name: testVM, GUID: 98321741-A936-4128-8AB0-07099B23E25C) uses 
  multiple disks with the same disk Id.
  Disk Id: 7198C033-AB5D-4585-905D-0DA68D26F9C5  Disk path: E:\VMs\testVM\testVM1.vhdx
  Disk Id: 7198C033-AB5D-4585-905D-0DA68D26F9C5  Disk path: E:\VMs\testVM\testVM2.vhdx
  You may lose optimization during the backups for the above listed disks.

  To perform incremental backup of these virtual disks, assign a unique ID to each disk. For example, you can use the Set-VHD PowerShell cmdlet to reset the disk ID for testVM1 as follows:

  Set-VHD -Path E:\VMs\testVM\testVM1.vhdx - ResetDiskIdentifier

  In the case of the differencing disks, you must run additional commands to re-create the disk chain. For more details on the Set-VHD cmdlet, see the following Microsoft TechNet article:

  https://technet.microsoft.com/en-us/library/hh848561.aspx

• Additional notes are available on Accelerator:

  See Accelerator notes and requirements for virtual machines.

• The following is due to a Microsoft limitation: NetBackup for Hyper-V does not support backup of encrypted vhd or vhdx files.

• The following is due to a Microsoft limitation; this note applies to the VSS backup method only. For the virtual machines that have a FAT or FAT32 file system, NetBackup supports only Hyper-V offline backup.

  See About Hyper-V online and offline backups for VSS.

• The WMI backup method (for Hyper-V Server 2016 and later) does not employ online vs offline backups.

  See WMI backup method: State of the virtual machine before and after restore.

• For the VSS backup method: If a virtual machine is in the Paused state when the backup starts, the virtual machine is placed in the Saved state after the backup completes.

• The WMI backup method supports the option Consistency level (on the policy's Hyper-V tab under Advanced). The available settings are Application consistent then crash sonsistent, Application consistent, and Crash consistent.

  For the WMI backup method, note the following:

  • If a virtual machine is in the Paused state during backup and Consistency level is set to Application consistent, the backup fails during snapshot creation. If Consistency level is set to Application consistent then crash consistent or Crash consistent, the backup succeeds. The virtual machine is in the Off state after the restore.

  • If a virtual machine is in the Saved state during backup and Consistency level is set to Application consistent, the backup fails during snapshot creation. If Consistency level is set to Application consistent then crash consistent or Crash consistent, the backup succeeds. The virtual machine is in the Saved state after the restore.

  See Consistency level parameter (WMI).

• NetBackup for Hyper-V has certain character restrictions for virtual machine display names.

  See NetBackup character restrictions for Hyper-V virtual machine display names.

• NetBackup for Hyper-V does not support restores with the Fibre Transport data transfer method.

• More information is available on the restore of Hyper-V virtual machines.

  See Notes on individual file restore.

  See Notes on full virtual machine restore.

• More information about NetBackup for Hyper-V support is available in the following documents:

  • The NetBackup Software Compatibility List:

    NetBackup Compatibility List for all Versions

  • Support for NetBackup in virtual environments:

    http://www.veritas.com/docs/000006177