I had a question recently on creating a Datastore cluster. The question was "I have datastores with VM's already on them, can I create a datastore cluster with these volumes?". The answer is Yes! I could not find documentation on this. Most of the documentation out there shows you how to create Datastore Clusters from scratch, but really they don't address currently populated volumes. Of course you do want to follow the guidelines for creating a datastore cluster (make sure they are not replicated volumes, same storage characteristics, VMFS or NFS volumes and correct tier of storage) . You would go through the same wizard to create the datastore cluster. Simply select populated or unpopulated datastores that you want to include in the cluster. From the VM's prospective, the storage volume will update to the new cluster name.