In addition to the SMO/SDU docs, the best thing to do is look up the configuration in the IMT and then reference the IMT Note (Alert/Info) details for your supported rows and on RDM support and Guests.
If you can't find what you need, use the IMT Feedback after your search and it will route your request to the right place.
For RHEL you need to use SDU to configure LUN (either iSCSI or FCP). Once the LUN is added, you can even mark them as ASM disks and use it for your oracle db. For windows -> SDW. See if the attached doc is useful.
>> "I do not see any need to create/configure LUN using SDU - I am not using FC or iSCSI from guest os as I would use if I were using physical machine - RD mapping is going to occur over FCoE from ESXi host and storage, transparently to guest os"
SnapDrive for Unix (SDU) / Snapdrive for Windows (SDW) is required for SnapManager for Oracle (SMO) to work. Existing storage/LUNs can be used. SDU/SDW will recognize and be able to use existing LUNs.
You can use the “snapdrive storage connect” command to connect the storage entity to the host.
The following article talks about Connecting to an RDM LUN on a guest OS. (This is for windows)