SUMMARY:Need quick education on channels in A1000 array

From: Judith Reed (
Date: Fri Feb 12 1999 - 09:27:26 CST

I asked about how many channels are on a 12-drive A1000 array, and how
to arrange disks across them, since the config. utility was telling me I
was creating a diskgroup across multiple disks on the same channel, and
advising against it. I received several responses, and observed a few things
myself. Here's how the channels seem to be laid out, and our config is
marked on it.
  _____________mirror set____________
  | _____________mirror set______|_____
  | | | |
(1,0)(1,1)(1,2)(1,3)(1,4)(1,5) || (2,0)(2,1)(2,2)(2,3)(2,4)(2,5)
            | | | | | | | |
            | | | | | | | |
            ------------------ RAID 5 set --------------------

I only got two responses, which are appended. Thanks to those who replied.
> Of course, to get more than an 8GB raid 5 "disk" using 4GB disks, it is
>then inevitable that I'll be creating "drives" across the same channel, and
>there's nothing that can be done about that, correct?

 My understanding is that the A1000 looks/acts just like the D1000.
There are two sets of six disks, split left/right in the box as
cnt0d0-cnt5d0 (left) and cnt8d0-cnt13d0 (right) with two SCSI channels, one
serving the six disks on the left side, and one serving the six disks on
the right in the default configuration. The box can be configured to serve
all twelve drives through a single SCSI channel if only one channel is
available on the host.

It seems to me that if you were building the six disk RAID5 set all on one
side of the box, that would lead to the "same channel" message.

---> Editor's note - I haven't found anywhere you actually can see the
"cnt0d0-cnt13d0" designations of the disks - they only seem to show up with
the designation "(1,0),(2,0),etc.." Also, it appears the complaint has to
do with the fact that my raid set spans more than one disk on the same channel.

Judith Reed
(315) 453-2912 x335

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