Some snapshot caveats in Hyper-V
I love VMware Workstation. But I also like to expand my horizons so a long while back, I picked up a couple of servers to run Hyper-V and ESXi in my home lab. I have a bunch of ESX hosts at work, but I can’t "play" with those.
Because I do a lot of testing, I also tend to make heavy use of snapshots and, although I’m sure my "discoveries" are well documented, I decided to share with you two things I’ve run across when using snapshots in Hyper-V.
For a while, when I took a Hyper-V snapshot, I was willing to live with the fact that the snapshot didn't have a name - just a date and time. But, after years of using VMware Workstation rather than Hyper-V for my home lab, I liked VMware's snapshot naming better.
Until I realized that I'm blind.
In Hyper-V, you can rename a snapshot to be something more meaningful than a date and time stamp. After all, "Pre-DPM deployment" is a lot more descriptive than "10/23/2010 1:14:56 PM"
To rename a snapshot in Hyper-V, simply take the snapshot, then right-click the new snapshot and click Rename and type in a descriptive name for the snapshot. I guess I should have just looked harder before.
Pass through disks
If you’re using a pass through disk in a Hyper-V-based virtual machine, you can’t snapshot that virtual machine. A pass through disk means that the virtual machine is making direct, non-virtualized use of a physical disk. Once you use one of these in your VM, snapshots are no longer possible.
Synchronization can be a gotcha
If you’ve created an entire Active Directory forest, be careful about how you use snapshots. Whether you’re using Hyper-V or you’re using ESX or you’re using VMware Workstation, you can get yourself in trouble. Consider the following: Suppose you’ve created an AD domain that included ten servers and then you revert to a snapshot of the domain controller as it existed before you joined any of the other servers to the domain. You’d quickly discover that the reversion breaks your entire setup.