Well, the OSF-managers save the day again! I asked how to combine the dual
SCSI buses on one of the internal shelf of an AlphaServer 2100 into a
single SCSI bus. Thanks to:
Alex_Nord_at_jabil.com
barnwell_at_jbsvax.eksystems.com
kalle.flodkvist_at_its.uu.se ,
who all informed me that it is as simple as swapping the positions of the
jumper and terminator plugs. These plugs are the only two large plugs on
the backplane and they both have small circuit boards attached to them.
In the default dual-bus configuration, the jumper plug (the slightly
smaller plug with "Jumper" discretely written on it) is in the top slot and
the terminator in the slot at the bottom. For a single bus, the positions
are visa versa. With a single bus, connect a single RAID (or SCSI) channel
to the topmost 68-pin SCSI connector and it controls the whole shelf. SCSI
slots 0-3 are in the odd-numbered slots (counting from the top of the
shelf), and 4-7 in the even numbered slots.
kevin reardon
The original question:
>This may be one of those dumb questions, but I'm trying to install some new
>disks in the two internal shelves of an AlphaServer 2100 4/266. Up to now
>we've had 8 disks in one shelf split between two channels on a SWXCR RAID
>Array 230 3-channel controller. The two internal shelves are each made up
>of two separate buses of four slots each (for a total of sixteen slots). I
>can't figure out how to connect two buses on one shelf in order to have a
>single bus that can handle up to eight disks. If I can't connect the buses,
>I have to use a separate RAID controller channel for each bus, which means
>a maximum of 12 disks on my controller instead of 21!
>
>The manual for my AlphaServer 1000A goes into great detail on all the
>different possible configurations of the backplane (pages 6-22 and
>following). The manual of the AS 2100 is quite defficient in this regard
>(page 3-42). In particular, for the AS 1000A it is explained how to set the
>cables and jumpers to get a single SCSI bus on the backplane (the AS 1000
>series only having a single 8-slot internal shelf).
>
>I've tried putting a jumper cable between the buses on the backplane and
>tried all the possible jumper settings of the four jumper pins I found
>hidden on the backplane, all without success. The jumper cable alone seems
>to produce two slots with the same SCSI address on each shelf. Setting any
>of the jumpers seemed to keep any of the disks on that shelf from spinning
>up at all.
>
>Has anyone ever setup an AlphaServer 2100 to use only two SCSI or RAID
>channels for all the internal disks? How do I get a single SCSI bus on one
>of the internal shelves? Or is there a reason this doesn't seem to be
>documented anywhere?
Received on Thu Jul 10 1997 - 15:22:52 NZST