I'm using Hyper-V on Windows Server 2008 R2. I have one virtual machine that writes constantly to its vhd, using between 60% and 100% of the maximum disk I/O according to Resource Monitor. This makes other VMs on that server very slow.
This VM is doing useful work so I don't want to shut it down. Is there any way in Hyper-V limit the amount of disk I/O? Or reduce the priority of that VM?
No. You will either need to change your storage. Whether it is a faster disk, or separate the .vhd to another spindle entirely, or make it a physical server.