Sure, Cluster Shared Volumes (CSV) is new technology in Windows Server 2008 R2 that will allow us to share the NTFS file system. This technology will allow Hyper-V to break the 1 VM per LUN limitation we had and help with things like Live Migration. It isn’t required for Live Migration, but it helps. With that said, CSV protects the VMs by ensuring that only one system can power on a VHD at a time. It also provides redundant paths to the storage, and if the path to the storage goes away, it will allow access to that storage through another node on the cluster. See here for more information.