We use Hyper-V and just create a single large volume for each server and store the .vhd's on that. Doing it this way gives you the ability to move vhd's around if needed. Also less headache when having to deal with the number of volumes on the DSS. Might not be as fast as doing passthru straight to a volume on DSS, but manageability is much better. Also, you lose a few abilities with Hyper-v like being able to export volumes, etc when doing passthru SCSI.