Found this very interesting paper from VMware relating Storage DRS compatibility with most storage functionalities: http://www.vmware.com/files/pdf/techpaper/vsphere-storage-drs-interoperability.pdf
Quick search the guide provided by Rafa.
VMware supports vSphere Raw Disk Mapping in Storage DRS.
This statement is on page 8/11.
VMware vSphere Raw Disk Mapping
vSphere 5.0 fully supports the use of Raw Disk Mapping (RDM) in combination with Storage DRS. The target LUN that is dedicated to an RDM disk will not be managed by Storage DRS, but it will manage the pointer mapping file for an RDM disk. Pointer files are managed in the same way as the other disk files of a virtual machine. Storage DRS is able to place a virtual machine with an RDM pointer mapping file, as well as relocating the virtual machine. Cloning virtual machines and adding disks with pointer files are also supported by Storage DRS. If a datastore is placed into maintenance mode, Storage DRS will migrate the pointer file to another datastore in the datastore cluster. If the virtual machine is configured with a VMDK anti-affinity rule, it will be unlikely for Storage DRS to move the RDM pointer file for space balancing because the pointer file is very small.
In addition, I/O load balancing is effectively disabled for RDM because the pointer files themselves are not involved in I/O, and the I/O to the target LUNs cannot be redirected by Storage DRS.
So, just to make sure this is clear - as the text can be a little tricky: SDRS is supported with VMs that has RDMs and will move RDM pointers, but will NOT move the RDM LUN itself.
Please refer to the documented in the SRM releasenotes: http://www.vmware.com/support/srm/srm_releasenotes_5_0_0.html
Interoperability with Storage vMotion and Storage DRS:
Due to some specific and limited cases where recoverability can be compromised during storage movement, Site Recovery Manager 5.0 is not supported for use with Storage vMotion (SVmotion) and is not supported for use with the Storage Distributed Resource Scheduler (SDRS) including the use of datastore clusters.