Microsoft has issued an important update for Azure Site Recovery (ASR). The service now supports managed disks, which allows customers to attach disks to machines during migration to Azure. This release is an evolution of managed disks support, after it first came to Azure cloud in February.
Introducing this support to Azure Site Recovery allows for simpler disk management for Azure IaaS virtual machines. Microsoft points out that this removes problems with managing storage for machines after failover.
Additionally, the new ability also improves general reliability for Availability Sets. ASR can now automatically place failed over VMs into different storage scale units. This means the platform can avoid single points of failure.
In its announcement, Microsoft says managed disks can only be created for virtual machines deployed using Resource manager model. Another limitation is that VMs with managed disks must be part of availability sets with managed disks turned to yes.
The company points to other considerations for using this additional support:
- If the storage account used for replication was encrypted with Storage Service Encryption (SSE) at any point in time, creation of managed disks during failover will fail. In such a scenario, you can either set “Use managed disks” to “No” in the Compute and Network settings for the virtual machine and retry failover or disable protection for the virtual machine and protect it to a storage account which did not have Storage service encryption enabled at any point in time. Learn more about managed disks and Storage service encryption.
- For Hyper-V VM's managed by/not under the management of System Center VMM, set the option to use managed disks only if you intend to migrate your machine to Azure. This is because failback from Azure to on-premises Hyper-V environment is not currently supported for machines with managed disks.
- Data from on-premises VMs replicates to a target storage account in Azure, as is with the experience today. Managed disks are created and attached to your machine only on a failover to Azure.
- Disaster Recovery of Azure IaaS machines with managed disks is not supported currently and will be made available in the future.
Azure Site Recovery gets Disaster Recovery Options
Earlier this month, Microsoft introduced new disaster recovery options within Azure Site Recovery. The new ability allows users to restore Azure virtual machines running in the public cloud platform.
Microsoft Principal Program Manager Rochak Mittal explained how the service works:
“As you move production applications to the cloud, Azure natively provides you the high availability and reliability that your mission critical workloads need. However, compliance requirements such as ISO 27001 still require that you have a provable disaster recovery solution in place as part of a business continuity plan (BCP). The set of features that we are announcing today for Azure IaaS fill this important need.”