Data Recovery (and native VHD data integrity issues)

There are a couple of important considerations with the use of native VHD based imaging. These are particularly necessary to think about when you are creating an imaging system that is based around the native VHD boot capability

Firstly, computer hibernation is not supported. Microsoft hasn’t particularly provided us with any reason why this is the case; they just state that that is so. This could be an issue with laptop computers.

Secondly, and this is the big one, all of your C drive is stored in that single file. In theory, this increases the risk of data loss from a disk if for some reason that single file is affected by errors on the physical hard disk.

Let me expand a bit on the second scenario. From time to time we see laptops that have a damaged hard disk. Even if the computer can’t boot Windows it is usually possible to recover most of the files on the disk simply by copying. It is rare to lose all of the data on the disk in a situation where there are only a few files that may be unreadable.

If you extrapolate this into the Native VHD scenario then if all your data is stored in a single file and that file becomes unreadable, then normal scenarios for copying files will not work. You will have to consider whether scenarios exist where you might be able to recover only part of the file and if there are any data recovery tools or systems readily available that can retrieve files from a damaged or partially recovered VHD file.

I have just about completed a deployment of laptops with Native VHDs and this scenario has somehow escaped me up to this point. It is very rare for me to have to deal with a situation where a hard disk fails to the point that data cannot be recovered off it, or it is unreadable by Windows (or Windows PE). Usually if there is a small amount of bad sectors I would boot to PE and then use Robocopy to copy as many files as possible onto a backup disk. If a few files got missed because of corruption we would look at recovery scenarios but this has never happened.

Imagine if a VHD file could not be copied in its entirety then you would have to make use of more sophisticated data recovery scenarios. There are some good Rescue CD options for this.

My idea for the moment is to take a look at V2P scenarios. I will post again later on once I have looked further into this scenario.