Swapping the OS Disk for an Azure VM

You can perform an "attach disk" restore that swaps the OS disk of an existing VM with a different OS disk.

When you swap OS disks, the original OS disk of the destination VM is retained in the Azure portal.

Encryption for swapping OS disks is handled as follows:

• If the OS disk of the destination VM is encrypted with ADE, and the OS disk of the source VM is not encrypted, then the restored OS disk is encrypted with ADE.

• If you swap an OS disk with source and destination VMs that are in different regions, then the restored OS disk is encrypted with server-side encryption (SSE) using a pairwise master key (PMK), regardless of how the OS disk of the source VM is encrypted.

• If the OS disk of a Linux source VM has fstab entries of drives that do not have the nofail setting applied, then the restored VM cannot be restarted because the Commvault software is unable to mount the drives.

Requirements

• For the disks that you want to swap, the following must be the same:

  • Generation (Generation 1, Generation 2)

  • Operating system (Windows, Linux)

  • Processor type (Arm-64, x64)

  • Security type (Trusted launch, Standard)

• If a passkey is configured for restores, you must have the passkey.

Limitations

OS disks cannot be swapped in the following cases:

• From backups of unmanaged VM disks

• From backups of encrypted VM disks

• To multiple destination VMs that are part of the same Cloud Service group

• For a VM based on an Azure VM image that has a plan

• For a source OS disk that is encrypted with Azure Disk Encryption (ADE)

Procedure

Select the Disk to Restore

1. From the Command Center navigation pane, go to Protect > Virtualization.

   The Overview page appears.

2. On the VM groups tab, in the row for the VM group that contains the disk, click the action button , and then click Restore.

   The Select restore type page appears.

3. Select Attach disk to existing VM.

   The Attach disk to existing VM page appears.

4. To select a specific MediaAgent and/or source for the restore, in the upper-right area of the page, click the Settings button .

   By default, the Commvault software automatically selects the MediaAgent and source as follows:

   • MediaAgent: The software uses the MediaAgent that performed the backup.

   • Source: By default, the software searches for the requested data in the primary copy. If the data is not found in the primary copy, the software selects a secondary or auxiliary copy.

   For more information, see MediaAgent and Copy Precedence Considerations for Virtualization Restores.

5. Select the disk to restore, and then click Restore.

   The Restore options dialog box appears.

Select the Hypervisor and VM to Restore the Disk To (Admin Users Only)

1. For Destination hypervisor, select the hypervisor to restore the disk to.

2. For Access node, leave Automatic (the default value) selected, or select an access node or an access node group.

   If you select Automatic, the Commvault software performs the restore using the most suitable access node from the destination hypervisor.

   If you select an access node group, the Commvault software performs the restore operation using the most suitable access node that is available in the access node group.

   For access node selection, the Commvault software checks for the same region. If no region match is found, then any of the available access nodes from the selected destination hypervisor or access node group is used.

3. For Destination VM, select the VM to restore the disk to.

4. For Disk name, you can enter a different name for the restored disk.

   If you do not enter a new disk name, a unique disk name is created automatically including a time stamp.

5. For Storage Account, select the storage account to restore the disk to.

6. To attach and swap the OS disk of the source VM, select Attach and swap OS disk.

Select the VM to Restore the Disk To

1. For Select destination VM, select the VM to restore the disk to.

   Only VMs that you have permissions for are available to select.

2. For Disk name, you can enter a different name for the restored disk.

   If you do not enter a new disk name, a unique disk name is created automatically including a time stamp.

3. Click Submit.