[rescue] RSM2000 controller

Jonathan Katz rescue at sunhelp.org
Thu Jun 21 01:07:17 CDT 2001

Richard wrote:
> I have four of the OSM3000 array trays that come with the A3000/RSM2000 
> but I did not inherit the controller with them.  

Ahhh, those are nice. 7 drive shelves, hot swap for SCA disks. SE to
the disks, differential to the controller/host. Just so you know where
I'm coming from, I have a fully-loaded (35 disk) RSM2000 at home.
> I am trying to track down an RSM2000 controller for these or figure out 
> some way to make them work with a third party (IBM ServeRAID) controller. 

You don't need a RAID controller on the host. You need a differential
SCSI sbus or PCI card and then the RAID controller (RSM2000) actually
does the hardware raid out to the drive trays. Beyond that you need
RAID controller software on your host for a Symbios Logic SCSI RAID
controller-- in other words RAID Manager 6.22 which you can download
from www.sun.com/downloads.

If you want to use the RSM Tray/JBODs you can attach ONE of them to a
host-based hardware RAID controller (like your IBM ServerRAID PCI
card) and then that CARD does the RAID operations on the drive tray.

>  The trays seem to be slightly different than the Unisys (the real 
> manufacturer) documentation states in that there is only one 68 pin 
> connector and no way to terminate them.  I would assume the RSM2000 
> controller provides the termination, however, my current IBM controller 
> does not support this.

The trick is each drive tray is on its own scsi bus from the controller.

IIRC the RSM trays are self-terminating, and don't require terminiation
from the controller. The other item to look out for is that the RSM
trays have a switch which sets it to "high" or "low" mode. The default
in the RSM2000 installation is "high" mode (SCSI IDs 7-14). That may
conflict with the IBM RAID card you have and you may need to set it to
low. By default they're set to high because the SCSI Initiator ID on
the RSM2000 controller is SCSI ID 5!

The other thing to keep in mind is that each individual RSM Tray is
expecting a differential SCSI connection.
> In short, does anybody either have an RSM2000 controller for sale, know 
> where I can get the proper Unisys (OSM1000) IO boards, or know if the 
> (Sun modified) OSM3000 trays can be used with other controllers and if so 
> which one(s)?

Terminology-wise, the RSM2000 has an RSM2000 controller and then up to
5 RSM trays with 7 drives a piece. Any PCI or sbus-based hardware raid
card which does differential scsi can control a single RSM tray JBOD.
Each individual RSM tray is a differential JBOD. The RSM2000 controller
is almost identical to the one in the A3000 and A3500. Note that at
one point in time the RSM2000 was rebadged the A3000 and then the first
rev A3500s were also released with the name A3000. Quite confusing.
They all take the same firmware and do the same thing (control 
differential JBODs and manage them as a hardware RAID array.) You could
essentially drop a bunch of loaded D1000s into an RSM2000 and it would
support the D1000s and act like an A3500. You should also be able to
replace the disks in an RSM2000 with something greater than 9GB and
still have a usable array, since it takes the same firmware as the
A3500s which are qualifed to have disks up to 36GB installed.

I hope this helps. I can always find more info on this stuff if you're
so interested.


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