Can we get away with using RDM for MSCS on a ESX 4.0 host-host active/passive cluster
We are considering an active/passive cluster for our SQL 2008 Standard R2 database server in our remote datacentre. Currently there are two ESX hosts out there so we want to have clustering across hosts incase one fails. The SQL server is running Windows Server 2008 Ent R2. The shared storage is an AMS2100 with SAS drives. The SAN has built in thin provisioning so LUNs are created from an over-alocated storage pool.
The big question is that we want to use VMFS for the cluster and not RDM if at all possible. This enables easy backup of the Virtual Machine. Can we use VMFS drives only?
Also, if anyone else has been through this I'd like to hear other suggestions on how to provide redundancy for SQL and what you would recommend. Clustering is only a consideration at the moment.