Virtual block devices can be stored on FibreChannel disk subject to the following limitations:
Back end block device names (for example, c0t0d0s2) must be the same for migration to succeed. If device names are different, migration will fail.
For FibreChannel devices, it is likely that the cX number will be different if scsi_vhci, described in scsi_vhci(7D), is not used. If scsi_vhci is used, device names are likely to be identical. If scsi_vhci is enabled and has never been disabled, the controller should be at cX on x86/x64 machines.