http://kb.vmware.com/kb/1005241 - This video discusses some of the common questions that arise when migrating virtual machines that utilize Raw Device Mappings (RDMs).
1. Warm migration (vMotion), where the virtual machine state as powered on.
2. Cold migration, where the virtual machine state as powered off.
3. Storage migration (Storage vMotion), where the virtual machine state as powered on.
Be sure to read the full content of the KB article for step-by-step instructions and much more additional information: "Migrating virtual machines with Raw Device Mappings(1005241)" at http://kb.vmware.com/kb/1005241
Note: For best viewings results, ensure that the 720p quality setting is selected an view using full screen mode.