Hotfixes for DPM Protected Hyper-V Guests

One of the things that isn’t made 100% clear in the DPM documentation is what you need to do for Hyper-V VM’s that you are protecting at the Hyper-V host layer.  The “Protected Computer Software Requirements” document on Technet tells you that you need to apply certain hotfixes to the Hyper-V host, and you could be forgiven for thinking that was all you needed to do.

However, if you remember that when DPM uses the Hyper-V VSS Writer to take a snapshot of a running VM, it also leverages the in-guest VSS Writers to ensure that the guest itself is consistent inside, so we are able to have application consistent backups.

What’s the implication of this?  If there is a hotfix required in the physical world (for instance a file server running Windows Server 2003 requires hotfixes 940349 & 975759) then you should also have that hotfix applied to your protected VM’s, even though you aren’t running a DPM agent in that VM.  Essentially treat any machine you are protecting the same according to the “Protected Computer Software Requirements” document, regardless of whether it is physical or virtual, and protected at the host or guest level.