After lots of feedback, Microsoft Azure has added public preview support for backing up and restoring virtual machines that use Premium Storage. This article will explain what that means for you.
Most people who are new to cloud or hosting assume that any hosted virtual machine will be backed up by default and for free. That is usually not the situation. In the case of Azure, Microsoft only added generally available support for backing up virtual machines in the second half of 2015, years after we were able to run virtual machines in Azure!
Azure Backup for IaaS virtual machines protects and restores virtual machines as an atomic unit, the same way that you might back up and restore Hyper-V or vSphere virtual machines: You back up a machine, and if that machine is lost, then you restore the entire virtual machine. I’ve had to use Azure Backup to restore my own web server, and I was glad that it worked as advertised.
Unfortunately, Azure Backup for IaaS virtual machines did not support virtual machines with Premium Storage. This caused a problem because this is the choice of storage for those that need really high IOPS or low storage latency. In fact, Microsoft even advises the use of DS-Series virtual machines for SQL Server. (As an aside, that’s not necessarily a good recommendation for the common small database because it will cost a fortune.)
So if Premium Storage is recommended for big and critical workloads, you would expect that you should be able to back up and restore those workloads, right? The answer was no, you could not, and that led to a lot of feedback from Azure customers.
My experience with Azure, and especially with the Recovery Services teams, is that they love constructive feedback to improve their products. And I wasn’t surprised to see the following tweet by @AzureBackup:
What You Need to Know
Microsoft has launched support, in public preview stage, for protecting virtual machines with disks in Premium Storage. This is a preview, so it’s not recommended for production systems – although I suspect more than just a few customers will start using this feature with production workloads.
You should note that the backup process of a virtual machine with disks in Premium Storage causes a staging location called “AzureBackup-“ to be created in the same Premium Storage account. This staging location is a container. The staging container stores a page blob for the duration of the snapshot, and it is the same size as each of the Premium Storage disks that are attached to the machine that is currently being backed up. This will have some impact on the cost of your Premium Storage account.
Microsoft recommends that any restores are done using Standard Storage (HDD) – this is apparently the most cost-effective restoration process:
- Recover the virtual machine from the selected recovery point to a Standard Storage account.
- Copy required disks to Premium Storage.
- Create an Azure virtual machine and attach the required disks.
In my tests, I created a DS-1 virtual machine in the North Europe region that had two disks:
- 127 GB OS disk on Standard Storage
- 127 GB data disk on Premium Storage
The first backup took 14 minutes, and the backup size was 11,038 MB.
- Deleted all traces of the virtual machine, including the storage account and network (the entire resource group)
- Restored the virtual machine to a new cloud service (with new Standard Storage account and virtual network)
Twenty minutes after starting the restore, I was able to log into the virtual machine.