Azure Backup: as the solution evolves

Microsoft recently announced important news regarding the protection of virtual machines using Azure Backup. Thanks to an update of the backup stack you can get consistent improvements that make the solution more powerful and extend the potential. In this article will be investigated the benefits obtained by the update and will be examined the steps to switch to the new backup stack.

Features introduced by the new backup stack

Instant Recovery points and performance improvements

The Azure Backup job for the protection of virtual machines can be divided into two distinct phases:

  1. Creating a snapshot of the VM.
  2. Snapshot transfer to a Recovery Service vault.

Figure 1 - Steps of the backup job

Updating the backup stack, the recovery point is made available immediately after you create the virtual machine snapshot (Phase 1), and it is usable for restore operations according to the known methods. Unlike before that it was possible to use it only at the end of phase 2. From the Azure portal it is possible to distinguish the type of recovery point, as at the end of phase 1, the recovery point type is defined as "snapshots", while at the end of the snapshot transfer to the backup vault, the recovery point type is marked as "snapshot and vault".

The snapshots created during the backup process are maintained for 7 days. With this change are reduced considerably the execution time of the restore, carried out using the snapshots, which can be used in the same way to the checkpoint created by Hyper-V or VMware.

Support for large disks

The new backup stack also allows you to protect disks of size up to 4TB, both typologies: managed and unmanaged. Previously the limit in the maximum size of protected disks was 1 TB.

Distribution of disks during the recovery of virtual machines

After the upgrade of the backup stack you have the option to choose where to place the disks unmanaged of the virtual machines during the restore process. This reduces the configurations that would be necessary, post restore activities, putting all disks within the same storage account.

The Upgrade process

In order to enjoy the benefits introduced by the new backup stack you must manually upgrade your subscription which owns the Recovery Service Vault in the manner later described.

Consideration Pre-Upgrade

Before dealing with the upgrade of the stack you should consider the following aspects:

  • Since the upgrade is enabled at the Azure subscription level, the method of performing backups is changed for all protected virtual machines, present in the specific subscription. In the future it will be possible to have more granular control of this upgrade process.
  • The snapshots are saved locally to speed up the process of creation of the recovery point and to increase the speed of the restore processes. This means that there will be costs for the storage used by the snapshots preserved for 7 days.
  • The incremental snapshots are saved as page blob. For those who use managed disks there are no additional costs, while those using unmanaged disks must also consider the cost of the saved snapshots (during the 7 days) in the local storage account.
  • In the event of restore of a premium VM, starting from a snapshot recovery point, will be present, when creating the VM performed by the restore process, a temporary storage location.
  • For premium storage account you need to consider an allocation of 10 TB, for snapshots created for the purpose of instant recovery.

How to upgrade

The upgrade can be performed directly from the Azure portal or through PowerShell commands.

By accessing the Recovery Service vault from Azure portal, a notification will appear which indicates the ability to perform the backup stack upgrade.

Figure 2 – Backup stack upgrade notification

Selecting the notification the following message will appear that allows you to start the upgrade process.

Figure 3 - Launch of the backup stack upgrade process

The same operation can be performed using the following Powershell commands:

Figure 4 – Powershell commands to register the subscription to the upgrade process

Upgrade backup stack generally takes several minutes (maximum two hours), but it has no impact on scheduled backups.


This major update of the Azure Backup stack shows that the solution is evolving to expand its capabilities and to ensure higher performance levels. To make a contribution with new ideas or vote the features that are considered most important for Azure Backup you can access this page. For more details on Azure Backup you can see the Microsoft's official documentation.

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