Hyper-v folder structure best practices

The most important part (in my mind) here is that you get your underlying disk configuration and RAID structure correct prior to worrying about the folder structure. It is most definitely nice to store your VHDs in the correct and most appropriate way, but the folder layout will not have any effect if the VMs are running on a slow, poorly configured disk array.

Remember that for VMs which need good read performance over write performance, look at placing them on a RAID 5 array. You can build this on your SAN with a minimum of 3 disks; you should consider either enterprise-class SCSI or SAS disks in your SAN for performance reasons. For a VM which will be accessing database files, the database files should be placed on a RAID 10 array, again with SCSI or SAS disks.

You should also consider configuring at least 1 disk as a hotspare, in the event one of the disks in one of the SAN arrays fails. And remember - there is no harm in using multiple arrays (RAID 5 and RAID 10) if that is necessary to store your VMs based on their function and disk requirements.

-tigermatt

We use RAID 10 for the Guests and Raid 0 for the Host OS. On a couple servers we are fortunate enough to have RAID10 for both. I don't like the default directories that Hyper-V uses and I created a folder on the RAID 10 disks just simply called "Virtual Machines" and then I have a folder under there for each VM/VHD. On some servers I have experimented with placing the snapshots in the default directory but I am on the fence about that.

There isn't really a "best practice" as to creating your folder structure. However, if you're interested, my preferred configuration is creating a global folder called 'Virtual Machines', and then a subfolder specifically for each VM which is running. So:

x:\Virtual Machines\VM1\Vm1.VHD
x:\Virtual Machines\VM2\Vm2.VHD
...and so on.

However, you need to be aware that this will not help with backups. When performing backups, you should either use Snapshots in Hyper-V, or stream data out of the VM machine using a product such as NTBackup or Symantec Backup Exec and Remote Agents. You should not back-up the VHD files directly, as they will be locked by the Hyper-V Server.

-tigermatt

Also if you are using a Domain Controller as a guest OR Exchange you DO NOT want to use snapshots to backup. Snapshots do not play well with either one of these. Every once in a while I actually take a VM offline and copy the VHD elsewhere to be backed up by Backup Exec. That way if I have to do a restore I can have the VHD ready first.