Backups

Commvault backs up all the virtual machines identified on the Content tab for a subclient, including virtual machines that are deployed in Azure Stack Hub.

You can perform full, incremental, or synthetic full backups of virtual machines. The first backup of a virtual machine is always a full backup, regardless of the selected backup type.

What Gets Backed Up

The following items are included in backups:

• Disks configured by users through the Azure Stack Hub portal

• Virtual machines configured with Azure Stack Hub unmanaged and managed disks. From these backups, you can restore full virtual machines and restore guest files and folders.

What Does Not Get Backed Up

The following items are not included in backups:

• Files or network drives that are shared in Azure Stack and mounted on a virtual machine.

• (Microsoft Azure limitation) If a VM is deployed through a template using dynamic disks, the VM is not protected and the backup job fails.

Backup Process

The backup operation includes the following stages:

1. Discover virtual machine in the Azure Stack Hub cloud based on subclient settings.

2. Create a client computer entry for each virtual machine discovered.

3. Identify the virtual machines targeted for backup and the VSA proxies that can be used to perform backups. VSA proxies can be installed on Azure Stack Hub virtual machines or on local physical or virtual machines.

4. Identify the disks associated with virtual machines targeted for backup.

5. Assign backup streams to proxies in round-robin sequence.

6. Engage the Virtual Server File System driver (VSCloudFS). The VSCloudFS driver is an on-demand driver that is used to upload pages and read data to or from the Azure Stack cloud. The driver is used for backups and restores of Azure Stack Hub virtual machines.

7. Create virtual machine snapshots in the Azure Stack Hub cloud. By default, Azure Stack Hub backups are crash consistent backups.

8. Clean up the Azure Stack mount point, and complete the backup job.

Backup Types

By default, backups use Changed Block Tracking (CBT).

You can perform the following types of backups, either immediately or on a schedule.

• Full backups: Back up the entire virtual machine. This is the most comprehensive backup.

• Incremental backups: Back up virtual machine data that has changed since the most recent backup.

• Synthetic Full backups: Consolidate virtual machine data from the most recent full backup with subsequent incremental backups.

For more information on backup types, see Backup Options.