Hi GlenC hope the below will help you
The RealTime server host does require access to the LUNs being protected. Essentially the RealTime server needs to see everything being protected - both the client HBAs and the storage array LUNs that those clients are writing data to.
You don't have to use vSANs, most people will just configure a few new zones where each zone has a unique target and initiator. The RealTime server has both initiator and target ports on its HBAs so you would essentially have these zones:
1. Zone from client host being protected (initiator) to RealTime server (target)
2. Zone from storage array LUN(s) (target) to RealTime server (initiator)
3. Existing zone already setup from client host (initiator) to the storage array LUN (target)
4. Recovery zone from RealTime server (target) to client host (initiator) for presenting recovery LUNs