Microsoft has recently announced the ability of Azure Site Recovery (ASR) to set up Disaster Recovery (DR) for IaaS VMs using managed disks. This feature allows ASR to become an all-encompassing disaster recovery solution for applications hosted on IaaS VMs, including those hosted on VMs with managed disks.

Managed disks allow for storage management simplification as well as the durability and availability for disk usage. When virtual machines on managed disks are being protected, Azure Site Recovery creates a replica managed disk in the target region corresponding to each managed disk of the production VM in the primary region. The replica disk becomes the data store for the source disk in the primary region and helps to avoid the need of creating multiple storage accounts to store data for the protected machines.

Here is an example of a protecting computer-generated machine with five managed disks.

  • Enable VM protection via the virtual machine experience or through the recovery services vault experience.
  • In case of the need to change VMs on unmanaged disks currently protected by ASR to VMs on managed disks, protection has to be disabled first. Next, convert them to VMs with managed disks and protect them back. Conversion of the VMs, while the protection is on, is not supported.
  • Depending on the performance requirements one can also specify the type of replica managed disk as standard or premium.
  • A cache storage account is created per recovery services vault in the source region and re-used across your protected VMs during the protection set up. This account temporarily stores any data changes on the protected machines until they are transferred to the secondary region. One account can handle the data changes for multiple VMs. Option to specify the cache storage account per VM is also available.


Protecting via the virtual machine experience

Fig 1: Protecting via the virtual machine experience


Protecting via the recovery services vault experience

Fig 2: Protecting via the recovery services vault experience

This feature is deployed in all Azure production regions where ASR is supported. Microsoft is planning to roll out this capability to national clouds soon.


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