RDM Conversion Info

Conversion by changing connection to an RDM, then convert to VMDK via storage vMotion

This method first changes the connection method of the in guest volume to an RDM, then converts it to a native VMDK after a storage vMotion. A very predictable and safe method as well, but offers the additional benefit that any maintenance window needed for conversion is NOT based on the size of the volume. It’s maintenance windows is only for the time in which you briefly power down the VM.

1. Make note of all services that touch guest volumes, and shut off, as well as temporarily turning them to “disabled”
2. Once complete, disconnect all in-guest iSCSI volumes, remove the Host integration Toolkit, disable iSCSI NICs inside the VM, and power down.
3. On the storage system present the iSCSI disk to all ESXi hosts
4. Scan the host so they see the disk
5. Add an RDM (Virtual Mode) disk to the VM and pointing it to the newly host mounted iSCSI disk
6. Power on the VM, verify the RDM mounted and apps and/or data is present.
7. Re-enable all services set to disabled earlier to their original settings.
8. Storage vMotion the VM, making sure to you go into the “Advanced” settings.
9. Move the c: VMDK to a LUN and move the RDM to a VMFS LUN (Then change the disk format from “Same” to Thick, Thin, or Thick Eager Zero on the RDM disk). Once the storage vMotion is complete the RDM should now be migrated to a VMDK.
10. Unmount the previous mounted iSCSI volume from the ESXi hosts and verify access and services are now running correctly.

The nice thing about this method is that the VM is up and in production while the storage vMotion happens. It also catches all of the changes during the move.