[rbranson]

Perhaps you don't understand how RAC works. A RAC cluster is cache-coherent with a shared disk system, in this case an EMC SAN. It's designed to be both scalable and fault tolerant. The replication would have been handled by the SAN itself, at the block level. There would be two completely independent (edit:DISK) cabinets that would replicate synchronously. Some software assumes synchronous replication and it's cheaper to just spend a ton of money on an expensive replicating SAN and Oracle RAC than it is to rebuild the software, so an async replication scenario is out of the question.

[gaius]

No, no, no. The standby is not open for queries in that scenario. How can it be? It's playing no role in this setup, all the work is being done on the storage, it's not even aware of it until you try to activate it and it takes ownership of the controlfile.