I've searched this site and google, and I CAN find information about how to back up Hyper-V virtual machines by using Windows Server Backup from the Hyper-V host in Windows Server 2008. You have to set up a registry key to enable the Hyper-V VSS writer, and then you can take online backups of your VMs.
However, all the information I have found is about a year old, and none of it has been updated for Windows Server 2008 R2.
I tried to run the "FixIt" .msi found here:
... but it said that it was not applicable to my operating system. So I am thinking either Windows Server 2008 R2 already has its VSS service for Hyper-V enabled, or it still needs to be enabled but the FixIt package doesn't feel comfortable operating on an OS that wasn't RTM at the time.
I went ahead and scheduled a windows server backup for 9pm tomorrow. It said it would take 86 GB, which means it MUST be counting those VMs. But will this backup fail?
Can anyone confirm whether you have to apply the same registry changes for R2?