Protecting Azure IaaS VMs with Managed Disks with Site Recovery

Microsoft Azure Site Recovery team has just announced the capability to protect Azure IaaS VMs with managed disks using ASR as a public preview in all ASR enabled regions. This was an important steps as lot of customers were expecting to protect their VM workloads with managed disks, compared to the previous unmanaged disk scenario.

A2A Managed Disk Architecture

The challenge here was how do you replicate disk without requiring a VM object. To overcome this hurdle, ASR uses one storage account, in source region which will cache the disks to the target region. This enables ASR to create a replica managed disk in the target region for each VM protected in the primary region and this replica disk will be the data store for the source disk in the primary region. One important thing to note is that the initial replication between the source and target happens externally using a snapshot at the VM level, so are delta syncs.

Things to Remember

  • VM protection can be enabled via VM settings blade or in the recovery services vault settings.
  • If you have VMs with unmanaged disks that are currently protected by ASR, you need to disable protection and convert the VMs to managed disks first as conversion from unmanaged to managed disks while protected by ASR is not supported.
  • There is an option for you to selected the type of the replica disks, to standard or premium. See below screenshot.
  • Only one cache storage account is needed to so store the data changes from source to primary regions, but you can leverage multiple cache accounts per VM as well.