Migrating physical RDP mapping to VMDK

According to Cormac Hogan at VMware, you can migrate a physical RDM to VMDK, the only 'gocha' is that the VM must be shutdown to perform the cold migration.i.e. no live Storage vMotion. I needed to do this migrate data from a EMC to EqualLogic array.
http://blogs.vmware.com/vsphere/2012/02/migrating-rdms-and-a-question-for-rdm-users.html

Doing this causes this error at the end of the operation :(

Incompatible device specified for device ’0′

One solution is to clone the disk using vmkfstools, but after the clone you need to remove the RDM and add the cloned VMDK by adding an existing disk to the VM configuration. My test was with a 40GB disk.

You can time the operation, I used this command


time vmkfstools -i /vmfs/volumes/lun1/test-vm/test-vm_1-rdmp.vmdk /vmfs/volumes/lun1/test-vm/test-vm_2.vmdk  -d zeroedthick



Clone: 100% done.
real    7m 54.56s
user    0m 0.63s
sys     0m 0.00s