In this video, learn the difference between Azure managed and unmanaged virtual machine disks, including the benefits of using managed disks.
- [Narrator] Microsoft recently introduced managed disks for our Azure virtual machines in addition to the unmanaged disks that we have been using since the dawn of Azure. Virtual machine managed disks were introduced in February of 2017 and they include both the Standard and Premium disk types. Managed disks provide for easier management. This includes the ability to snapshot and backup our disks. This provides a read-only point-in-time restore.
Incremental snapshots are not supported at the time of this recording in July of 2017, but according to the Azure website it will be available in the future. We can now also create hundreds of virtual machines from a custom image without managing storage accounts. Back in the olden day of unmanaged disks we'd have to design our storage account for the number of virtual machines. With managed disks this is no longer the case. There are several virtual machine benefits to moving to managed disks.
First one being scale. With managed disks we can have 1,000 virtual machines in a scale set. That is 10 times scale improvement. And we are no longer restricted to the 20,000 IOPS per storage account. Keep in mind that this is still the limitation when using unmanaged disks. As for security, we can apply RBAC or role-based access control to our disks. We can still use Azure Disk Encryption and Storage Service Encryption to keep the data secure at rest.
If you're currently using unmanaged disks and would like to convert to a managed disk you will be happy to learn that you do not, and I'm going to repeat, not, have to create the virtual machine. Also, you do not need to calculate or create those storage accounts. And finally, you can migrate to managed disks in minutes not hours. How cool is that? Let's go ahead and take a look at a visualization between managed and unmanaged disks. So we'll start off with managed disks first.
And this diagram may be a little off-putting if you've been using availability set which you should be. Traditionally to ensure that we meet Microsoft's SLA we would group our virtual machines in an availability set. This would ensure that our virtual machines were in a separate fault and update domains but there was always a chance that those disks would be housed in the same storage unit which is a single point of failure. If we compare that to the managed environment we still have all our virtual machines and availability sets.
That does not go away. But here you'll notice our disks are isolated between storage units, ensuring that if one storage unit goes down it will not affect the other disks or virtual machines. Now you may be really excited and going, "Yes! I'm really excited! "I'm going to move to managed disks!" But there's a couple considerations you need to be aware of before jumping in to them. First and probably the most important, is that managed disks only support locally redundant storage. So if you're looking for a high availability solution or you need geographically redundant storage you may not want to choose managed disks.
And second, you do not want to use managed disks for your virtual machine diagnostics. Continue to use the unmanaged disks for that. And that's all there is to managed disks. The key benefits being the managed disks provide the ease of management but remember, virtual machine managed disks are restricted to locally redundant storage.
- Designing data storage
- Azure Blob storage
- Creating Blob storage using PowerShell
- Azure Cosmos DB
- Securing Azure SQL Database
- Selecting the appropriate storage option
- Virtual machine storage tiers
- Managed vs. Unmanaged disks