Q: I recently upgraded one of my servers with a combination of new SSD and HDD disks with the intention of creating a storage pool and tiered storage for my Hyper-V VMs. However, after creating the storage pool with these new disks I was unable to create any storage tiers. When I was running the New Virtual Disk Wizard and I got to the Specify the virtual disk name dialog and the option Create storage tiers on this virtual disk was not enabled. What’s wrong?
A: Storage tiers in Windows Server 2012 R2 and Windows Server 2016 enable the server to automatically move the most frequently accessed files or hot data to fast SSD storage while less frequently accessed data or warn data is stored on slower HDD storage. However, for the New Virtual Disk Wizard to be able to create storage tiers the disks must be correctly identified with the MediaType property as a combination of SSD and HDD disks. If the disks have a MediaType of Unknown or UnSpecified the wizard will not be able to create storage tiers. To see how Windows Server has identified the MediaType for each disk you can run the following PowerShell command.
Get-PhysicalDisk | ft FriendlyName,CanPool,Size,MediaType
If you see the disks that you want to use in your storage tiers displayed with a MediaType of UnSpecified you will need to change the MediaType to the appropriate value of either SSD or HDD. It’s much more common to see this issue with HDD disks. You can change the disk’s MediaType using the PowerShell command like the one you see below. Substitute the value of the FriendlyName parameter with the name of the disk you want to change. The disk must be a member of a storage pool for this command to succeed. Do this for each of the disks that need to be a part of your tiered storage that are incorrectly identified.
Set-PhysicalDisk –FriendlyName PhysicalDisk2 –MediaType HDD