Storage for Hyper-V host isn’t so cheap, that’s even more true with high availability.
This is something you may don’t know, but by default, when you create a new VM, the “Automatic Stop Action” is “Save” :
As you can read on the screen-shot, the hypervisor will reserve the VM amount of RAM on the physical host disk (or SAN/SOFS) in the VM folder :
It can be pretty invasive with pretty big host, and pretty useless if the VM is on a cluster. Indeed, in a cluster, if a host shutdown, the VM will live migrate to an other host in the cluster.
Also, if you have a a personal lab on your laptop with a limited SSD capacity, it can save up some precious GB.
To disable that reservation, you can select one of the two other possibility, buy the GUI, or :
Get-VM | Set-VM -AutomaticStopAction ShutDown
This will affect all of the VM on the host.
Note : You need the VM to be off to perform that operation.