Monday, December 19, 2011

Backing up Hyper-V

In some ways this post is more of a heads up to something you can do with the 3X Systems backup appliance that you may, or may not be aware of. You can actually back up Hyper-V virtual machines (VM) at the VM level by making use of a standard file level backup set, and the use of the shadow copy service.

The ability to do this is nice if you run Hyper-V infrastructure because the built in Windows Server backup only allows for backup to occur at the volume level, meaning you have to back up the entire server just to get back a single VM. The alternative method, using our product will allow you to take a failed VM and restore the *.VHD and thus give you a crash consistent backup, without the need for restoring the entire volume (I'll cover how to do a backup in a more consistent way on my next post later in the week).

The first thing you need to do to accomplish this backup is to create a backup set on the 3X Manager for the Hyper-V machine in question. For the purposes of this article I set up a test machine here at our office. Here's a screen shot of my set up for the test client.

Going in to the backup set options most of what I have set up is the same as a run of the mill file backup. However the differences occur in the advanced options, and in the targets for backup. In this case my install has the default locations that were chosen by the Hyper-V server manager when I created the VM as the targeted directories. In the advanced options under the options tab of the backup set you have VSS options.

The correct settings here is to enable "Shadow Copy all files". This will make sure that we use the shadow copy service to copy the VM files without having to power down or pause the VM in question. Running the back up is the same as any other backup set, though due to the size of VHD files I might suggest doing a local seed if you are going to house the appliance at a DR location.

For a restore the process is also rather simple. All that needs to be done is a run through the restore wizard placing the VHD in an appropriate location. I do not suggest restoring to its original location if you have any worry of writing over the VHD as if the settings are muffed up this can happen. Once the VHD has been copied back over you can go into your Hyper-V manager and assign the new VHD to the VM through that configuration. If there is a desire for it I can post a video showing this process in order to make it clear.

Ryan Koch
3X Systems

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