DM-MP multipathing is not available on either the root or boot devices.
For more information about DM-MP multipath usage, see http://www.redhat.com/docs/manuals/csgfs/browse/rh-cs-en/ap-rhcs-dm-multipath-usagetxt.html. System re-IPL (shutdown -r) is supported on zVM guests only; not in LPAR mode.