I'm planning a redundant set-up for VMware. Two locations (about 8-12km distance) are to be connected with dark fibre for SAN connectivity. I am looking for a FC-SAN product that allows transparent failover for VMware Fault-Tolerance. This means, that if one SAN is offline the other SAN will promote the LUNs *automatically* .  

Neither NetApp nor EMC does seem to provide this featue... 

Any hint?