MP/IO that is not dependant on the WWID of the underlying multipath device
Causes no end of problems when migrating between SAN solutions when your server boots from SAN using device-mapper-multipath.
This is because multipath devices are hardcoded to the actual WWID of the lun (via /var/lib/multipath/bindings).
Migrate/replicate your boot lun to a new lun, the WWID changes and your server will no longer boot.