HP 9000 and HP Integrity servers support IBM System Storage® Multipath Subsystem Device Driver (SDD) dynamic pathing when you add more paths to a volume or when you present a new volume to a host.
For HP 9000 and HP Integrity servers, the SDD is aware of the preferred paths that the system sets for each volume. SDD is supported on HP-UX 11.0, 11iv1 and 11iv2. During failover processing, SDD tries the first preferred path, then the next known preferred path, until it tries all preferred paths. If SDD cannot find an available path using the preferred paths, it tries nonpreferred paths. If all paths are unavailable, the volume goes offline. SDD performs load balancing across the preferred paths where appropriate.