Backing Up Virtual Machines

You can back up virtual machines from a subclient or from a backup set (to include all subclients for the backup set). For each subclient, you must add the virtual machines to be backed up in the subclient content.


  • If virtual machines are encrypted using Azure Key Vault:
    • To perform backups, your Azure Key Vault and virtual machines must reside in the same Azure region and subscription.
    • You cannot run a backup for a Linux guest VM that has only the operating system disk encrypted (using Azure Key Vault). However, if this type of guest VM is included in a backup job, the job will not fail. The backup job will complete with errors (identifying the VM that is not backed up).

Before You Begin

  • Backups for virtual machines that contain a large number of files might take longer, because Commvault needs to break up large page ranges to ensure that pages can be read within the time limit that Azure sets for reads. To improve the speed of backups, defragment disks that contain large numbers of files before performing the backup.
  • For Azure volumes that were created by striping multiple blobs (virtual disks), it is recommended that you use an in-guest agent to protect the volume to ensure no loss of data. During the backup process, Azure is required to create a snapshot of each individual blob (virtual disk) in the volume using Azure API. These snapshots are taken consecutively (not simultaneously). If there is a time delay at any point during these operations, there is a possibility of data loss. To use an in-guest agent to protect the volume, refer to File System Backup and Recovery.


  1. From the CommCell Browser, expand Client Computers > virtualization_client > Virtual Server > instance > backup_set.
  2. Start the backup from the subclient or backup set:
    • From the subclient, right-click the subclient and click Backup.
    • From the backup set, right-click the backup set and click Backup All Subclients; then click Yes to confirm.
  3. In the Backup Options dialog box, choose the backup type.
  4. Optional: To schedule the backup, click Schedule.

    For more information on scheduling, see Scheduling.

  5. Optional: To further customize the backup operation, click Advanced.

    For more information about advanced options, see Advanced Backup Options.

  6. Optional: To save the current backup options as a script file, click Save as Script.

    For more information, see Save as Script Overview.

  7. Click OK to start the backup job.

    The VSA proxy coordinator assigns virtual machines to proxies for backup using round-robin logic.

You can track the progress of the job from the Job Controller. When the backup is complete, the Job Controller displays Completed.

After your backup job is complete, you can view the backup job history. For more information, see Job History.

Last modified: 8/20/2020 8:20:42 PM