Azure Site Recovery for Shared Disks

Hello Guys,

Azure Site Recovery (ASR) is a service that helps you protect your workloads from disasters by replicating them to Azure or another region. ASR supports various types of workloads, including Windows Server Failover Clusters (WSFC) that use shared disks.

Shared disks are a feature that allows multiple VMs to access the same disk simultaneously, enabling scenarios such as SQL FCI, SAP ASCS, Scale-out File Servers, and more. However, replicating shared disks can be challenging, as they require consistency across all the VMs and disks of the cluster.

That’s why ASR has introduced a new feature in private preview: DR for Azure Shared Disks. This feature allows you to protect, monitor, and recover your WSFC-clusters as a single unit across its DR lifecycle, while also generating cluster-consistent recovery points.

In this post, we will show you how to use this feature and what benefits it offers.


To use DR for Azure Shared Disks, you need to meet the following requirements:

  • You have a WSFC cluster running on Azure VMs with Windows Server 2016 or above.
  • You have attached one or more shared disks to the cluster using the Azure Shared Disks feature.
  • You have enabled ASR for the VMs in the cluster and configured the replication settings.
  • You have signed up for the private preview here.

How it works

DR for Azure Shared Disks works by replicating the shared disks along with the other disks of the cluster using ASR’s replication engine. The replication engine ensures that the recovery points are consistent across all the VMs and disks of the cluster, including the shared disk.

When you enable DR for Azure Shared Disks, you will see a new option in the ASR portal: Protect Cluster. This option allows you to select a WSFC cluster and protect it as a single entity. You can also monitor the protection and health of the cluster and all its nodes from a single page.

When you perform a failover operation, you can choose to failover the entire cluster at once, or select individual nodes to failover. ASR will automatically create and attach the shared disk in the target region and ensure that the cluster is up and running.


DR for Azure Shared Disks offers several benefits over the traditional approach of replicating each VM and disk separately:

  • Simplified management: You don’t need to worry about managing multiple replication policies, recovery plans, or failover operations for each VM and disk in the cluster. You can protect and recover the cluster as a whole with a few clicks.
  • Cluster consistency: You don’t need to worry about data corruption or application errors due to inconsistent recovery points. ASR ensures that the recovery points are consistent across all the VMs and disks of the cluster, including the shared disk.
  • Faster recovery: You don’t need to wait for each VM and disk to be recovered separately. ASR recovers the cluster as a single unit, reducing the downtime and complexity.


DR for Azure Shared Disks is currently in private preview and has some limitations that will be resolved in public preview:

  • The scope is limited to forward direction protection. Once a failover is performed, you will have to re-enable replication for reverse direction protection.
  • Any node ownership changes within the cluster (also called cluster failovers) will require a disk re-sync.
  • The feature does not support Linux clusters or clusters with more than 4 nodes.

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