You must install multipathing software on all IBM Power Systems AIX hosts that are attached to the system.
On IBM Power Systems hosts, the Subsystem Device Driver (SDD), the Subsystem Device Driver Path Control Module (SDDPCM), or the AIX Path Control Module (AIXPCM) provide multipathing support.
For more information about the multipath drivers, see http://www.ibm.com/support/docview.wss?uid=ssg1S1010218.