http://www.symantec.com/docs/TECH127089 states that non-appliance Linux backup hosts do not suport DMP.
Either add support for DMP; or allow NetBackup administrators to specify device paths to be used for SAN transport mode.
Example:
RHEL backup host has two paths to the SAN switch, and the datastore has two paths to the SAN switch, providing four logical paths and allowing for up to two links to be lost and still be able to access the datastore. The RHEL built-in drivers create four /dev entries for direct access:
/dev/sdd
/dev/sde
/dev/sdf
/dev/sdg
and a fifth /dev entry as a virtual device, where the OS will provide failover:
/dev/mapper/590000880000198400725633099304239
Without any control, NetBackup may choose to use /dev/sde to access the datastore, but that is a point of failure. If we could configure NetBackup in such a way that it will use the /dev/mapper/ device to access the datastore, then redundancy is provided by the OS.