Frequently Asked Questions - Virtual Server Agent for Microsoft Hyper-V

Table of Contents

How do I ensure migrated virtual machines are backed up?

If you change a virtual machine's GUID when you migrate the virtual machine from one storage location to another, auto discover does not recognize the migrated virtual machine, and the virtual machine is no longer automatically backed up.

  • When you migrate a virtual machine from one storage location to another, maintain the virtual machine's GUID.
  • If you change the virtual machine's GUID during migration, manually add the virtual machine to the subclient content after the migration is complete.
     

Can I keep virtual machines online while performing a backup?

You can keep a virtual machine online while performing a backup. Ensure that the virtual machine satisfies the following requirements before performing the backup:

  • Integration services are installed and the backup integration service has not been disabled.
  • Integration services on the guest virtual machine must be set to the same level as the host Hyper-V server.
  • All disks used by the virtual machine are configured within the guest operating system as NTFS-formatted basic disks. Virtual machines that use storage on which the physical partitions have been formatted as dynamic disks or the FAT32 file system prevent an online backup from being performed. This is not the same as dynamically expanding virtual hard disks, which are fully supported by backup and restore operations.
  • Volume Shadow Copy Service must be enabled for all volumes used by the virtual machine. Each volume must also serve as the storage location for shadow copies of the volume. Ensure that the sufficient space, required for the snapshot creation, is available on each guest volume inside the virtual machine.
  • The configuration files for the virtual machine are stored with the Virtual Hard Drive (VHD) files on the host. This will ensure that the virtual machine does not go into the saved state during the snapshot creation.
  • For Hyper-V Server 2012 R2 hosts, online backups are only supported if the virtual machines being backed up have SCSI controllers.

There are also some forms of storage in Hyper-V guest virtual machines that are not supported for backup through the Virtual Server Agent.

  • Physical disks that are directly attached to a virtual machine
  • Storage accessed from a virtual machine by using an Internet SCSI (iSCSI) initiator within the guest operating system.

 If these requirements are not met, then only offline backups can run and the guest virtual machine will be unavailable for the duration of the backup.

Can I filter virtual machines with a specific operating system?

You can specify the exact name of the operating system while defining the filter. For example: Microsoft Windows Server 2003 R2, Microsoft Windows Server 2008 R2 (64-bit), Windows Server 2008 R2 Enterprise

To get an exact name of the operating system, use one of the following methods:

  • Refer to the Auto registry key on the Windows virtual machine. The OSName string will display the exact name of the operating system on the virtual machine. The registry key is located at the following location:

    Windows_virtual_machine\HKEY_LOCAL_MACHINE\Software\Microsoft\Virtual Machine\Auto

  • View the Backup Job Summary report. This report displays the exact name of operating systems on all the backed up virtual machine if the virtual machine is powered on at the time of backup and integration services are installed on the virtual machine. For more information, refer to Related Reports.

Can I include virtual machines with a specific operating system into a subclient?

You can define rule to automatically include virtual machines with a specific operating system into a subclient. You must specify the exact name of the operating system while defining the rule. For example: Microsoft Windows Server 2003 R2, Microsoft Windows Server 2008 R2 (64-bit), Windows Server 2008 R2 Enterprise

To get an exact name of the operating system, use one of the following methods:

  • Refer to the Auto registry key on the Windows virtual machine. The OSName string will display the exact name of the operating system on the virtual machine. The registry key is located at the following location:

    Windows_virtual_machine\HKEY_LOCAL_MACHINE\Software\Microsoft\Virtual Machine\Auto

  • View the Backup Job Summary report. This report displays the exact name of operating systems on all the backed up virtual machine if the virtual machine is powered on at the time of backup and integration services are installed on the virtual machine. For more information, refer to Related Reports.

How is white space handled in virtual machine capacity licensing?

When capacity licensing is used, the used space as reported by the guest OS for the virtual machine is reported against licensed capacity. For example, if the guest OS shows 20GB used on a 100GB disk, 20GB is what counts against the licensed capacity. This is the case even if a different figure is reported for VM disks on the datastore, and is not affected by deduplication or compression.

How is capacity licensing calculated for virtual machines?

Virtual machine backup job data for capacity licensing usage is calculated as follows:

  • For streaming backups and backup copy jobs, the capacity usage is based on the guest size for all virtual machines being backed up.
  • For SnapProtect backups, the capacity usage is based on the application size for the virtual machines being backed up.

In the License Summary Report, the Job Size column lists guest sizes for virtual machines included in full or synthetic full streaming backups (including backup copy jobs) and application sizes for snapshots. 

Capacity usage is summarized as follows:

  • Virtual machine streaming backups are included in the Data Protection Enterprise Infrastructure or Data Enterprise Core Infrastructure license count (depending on the storage policy configuration).
  • Backup copy operations are included in the Data Protection Enterprise Infrastructure license count.
  • Archived VMs are included in the Data Archive Enterprise Infrastructure license count.
  • SnapProtect backups are included in the Data Protection Snapshot count.

When the same virtual machine is included in multiple backup jobs, only one of the jobs counts against capacity usage. If a virtual machine is included in multiple subclients, the latest backup provides the size included in overall capacity usage. If a virtual machine is included in both backups and archiving jobs, the guest size for the VM counts toward the Data Protection Enterprise Infrastructure or Data Enterprise Core Infrastructure license.

  • Service Pack 5 introduced capacity licensing based on guest VM size. To ensure that the capacity licensing details are accurate, you must upgrade SnapProtect Version 9 virtualization clients to Version 10. After the upgrade, make sure to run full backup jobs (not synthetic full).
  • Logical volume manager (LVM) metadata processing for volumes encrypted using BitLocker is currently not supported. Decrypting contents of such volumes may not be feasible during backup because decryption requires a recovery password or a decryption key. Because metadata collection for the volume fails, the reported guest size for virtual machines with encrypted volumes may be incorrect and a file-level browse operation for the encrypted volume cannot display file information.

Verifying Backup Job Data for Virtual Machines

To get a detailed listing of backup job data for each virtual machine, you can log in to the CommServer host using qlogin and run the following stored procedure on the CommServe database:

qoperation execscript -sn QS_CLAGetVSADetails –cs commserve_host_name –file file_name -format csv

The resulting output shows the size of the latest backup job for each virtual machine. The size value is the guest size for the VM, or the used space if guest size is unavailable; the size value for all VMs is used in the overall capacity licensing calculation.

The output also shows which license category each VM counts against, and provides instance, backup set, subclient, and job information for each VM.

How can I use the software VSS provider from Microsoft?

As an alternative to using a hardware VSS provider that is not supported or has not been tested, you can configure the VSSProvider additional setting to use the software VSS provider from Microsoft:

  1. To find the ID, run the following command on the client computer:

    vssadmin list providers

  2. Copy the provider ID for the software VSS provider from Microsoft.

    An example of a provider ID is 400a2ff4-5eb1-44b0-8a05-1fcac0bcf9ff.

  3. From the CommCell Browser, navigate to Client Computers.
  4. Right-click the client and select Properties.
  5. Click Advanced, then click the Additional Settings tab.
  6. Click Add.
  7. On the Add Additional Settings dialog box, provide the following information:
    • In the Name box, type VSSProvider.
    • The Category field is automatically set to VirtualServer and the Type field is set to STRING.
    • In the Value file, enter the VSS Provider ID for Microsoft.
  8. Click OK to save additional settings, advanced settings, and client properties.

Your backup operations will use the VSS Provider from Microsoft.

What are the BackupSnapshot.xml or AutoRecovery.avhdx files for Microsoft Hyper-V Server 2012 R2?

When using Microsoft Hyper-V Server 2012 R2 to back up Windows virtual machines with the latest integration services installed, a virtual machine checkpoint is created when the volume shadow is created. This operation causes some additional files to be included in the backup, including BackupSnapshot.xml and AutoRecovery.avhdx files for each disk. The checkpoint information is automatically merged as the volume shadow is completed, and does not exist for the lifetime of the backup; but these files appear when browsing the backup data.

When you perform a restore of a full virtual machine, these files are restored along with the virtual machine. After the restore, the files are automatically integrated when the virtual machine is powered on for the first time.

You can also restore a virtual machine disk file and use that to access the disk; the files produced by the checkpoint operation are not required for that restore. If you restore a virtual machine disk and use that to create a new virtual machine, the files created for the checkpoint are not included, and the resulting virtual machine is not necessarily application consistent with the virtual machine at the time of the backup.