If multipath is enabled in the 3PAR driver section and multipathd is running, then a different codepath is taken in the 3PAR driver that will map all visible ports on the c-vol host and the 3PAR, and the volume attach should work. It's clear from the output listed in the bug that multipath isn't enabled as there is only a single initiator_target_port mapping.
Make sure you follow what I mentioned in comment #2. The 3par driver stanza in cinder.conf needs those 2 options specified.
If multipath is enabled in the 3PAR driver section and multipathd is running, then a different codepath is taken in the 3PAR driver that will map all visible ports on the c-vol host and the 3PAR, and the volume attach should work. It's clear from the output listed in the bug that multipath isn't enabled as there is only a single initiator_ target_ port mapping.
Make sure you follow what I mentioned in comment #2. The 3par driver stanza in cinder.conf needs those 2 options specified.