VM Backup

Veeam Backup for Microsoft Azure performs VM backup in the following way:

  1. Veeam Backup for Microsoft Azure creates snapshots of virtual disks that are attached to the processed Azure VM.

Disk snapshots are assigned Azure tags upon creation. Keys and values of Azure tags contain encrypted metadata that helps Veeam Backup for Microsoft Azure identify the related disk snapshots and treat them as a single unit — a cloud-native snapshot.

  1. If you enable image-level backup for the backup policy, Veeam Backup for Microsoft Azure performs the following operations:
  1. Launches a worker instance in an Azure region in which a processed Azure VM resides.

By default, Veeam Backup for Microsoft Azure launches worker instances using automatically created virtual network. However, you can add specific worker configurations. For more information, see Managing Worker Instances.

  1. Reads data from a cloud-native snapshot, transfers the data to a backup repository and stores it in the native Veeam format.

To reduce the amount of data read from snapshot, Veeam Backup for Microsoft Azure uses the changed block tracking (CBT) mechanism: during incremental backup sessions, Veeam Backup for Microsoft Azure compares the new cloud-native snapshot with the previous one and reads only those data blocks that have changed since the previous backup session. For more information, see Changed Block Tracking.

Note

Veeam Backup for Microsoft Azure encrypts and compresses data saved to backup repositories. For more information on data encryption, see Architecture Overview.

  1. Deallocates the worker instance when the backup session completes.
  1. If you enable the backup archiving mechanism, Veeam Backup for Microsoft Azure performs the following operations:
  1. Launches a worker instance in an Azure region in which a backup repository storing backed-up data resides.
  2. Retrieves data from the backup repository and transfers it to the target archive repository.
  3. Deallocates the worker instance when the archive session completes.

Veeam Backup for Microsoft Azure stores the backed-up data depending on the type of the virtual disk attached to the protected Azure VM:

  • Snapshots created for managed virtual disks are saved to the resource group where the Azure VM belongs.
  • Snapshots created for unmanaged virtual disks are saved to the Azure storage account where the Azure VM resides.
  • Backups created for managed and unmanaged virtual disks are saved to the target repository.

For more information on Azure virtual disk types, see Microsoft Docs.

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