current environment is esxi 5 across all hosts and running vcenter 5.
about to begin the process of getting all datastore luns to vmfs 5.54.
we've read that if you storage vmotion guest that have rdms assigned to them, the rdm is copied to a .vmdk file during that process.
any truth to this? it makes no sense why this would occur.
It is possible to convert a virtual mode RDM to a vmdk, but make sure to select Advanced when doing Storage vMotion to select which guest disks you want to move.
My understanding is that if doing a cold storage migration (VM power off) the RDM will be converted to a VDMK file at the new destination, but not when doing "hot" Storage vMotion.
See this KB for details: http://kb.vmware.com/kb/1005241
Hello Richard, Tim,
It seems the RDM is only converted when it's format is changed(thin/thick). Else only the mapping file is moved from the source to the destination datastore: