A RedHat AS 4.0 has been allocated some extra storage in a HP MA800 SAN. I would be a TRU64 Unix admin and the command hwmgr -view devices would show all LUNS being presented to the system. I'm struggling to find an equivalent on RedHat.......

Determine the kind of Fibre Cards you have (e.g. QLogic) and go to the company's site to get their utility that rescans the SCSI bus. (Alternatively you could just reboot.)

NOTE: On Linux SCSI device designations can change based on order found. What was /dev/sda on one boot could be /dev/sdc on another boot if the device was found 3rd.

Also is there any HP software for use with this array? We run EMC Clariion here so use EMC PowerPath and Navisphere with the those arrays on Linux and HP-UX. It may be there is software similar to that on your Tru64 available for Linux. I'd check the HP site (itrc.hp.com) for that or maybe the software.hp.com site to see if there are any applicable downloads.