Q. Are Cluster Shared Volumes (CSVs) supported across nodes in multiple subnets?

A. No, all nodes participating in CSV must be in the same subnet. If you need multi-site storage, use something other than a CSV. Remember that when you move across subnets, you need IP changes within the virtual machine (VM) to function, DNS updates because of the IP change, and client cache updates. So you'll still have some downtime to the end user, even if the actual VM moves with no downtime with Live Migration. If you need real high availability, you need to look at VLANs between the locations to avoid the need to change IP addresses.