Thanks for the reply. I'm open to other options if these are not the only ones. I just need a robust file server for lots of data.
I would be able to rely on SAN snapshots with the RDM so I don't know if it is a big deal to lose that functionality from the VM host.. And we prefer using a file-based backup utility for File-servers because of the indexing and version tracking features. So I won't miss vmdk snap or clone backups.
Does regular Vmotion and HA work with Physical RDM?