[6998] in linux-scsi channel archive
Re: Scsi Subsystem Unstablities...
daemon@ATHENA.MIT.EDU (Robert Siemer)
Mon Aug 16 18:12:19 1999
Cc: linux-scsi@vger.rutgers.edu
In-Reply-To: <Pine.LNX.4.10.9908160630550.394-100000@excelsior.rkirkpat.net>
Date: Mon, 16 Aug 1999 16:23:02 +0200
From: Robert Siemer <siemer@i309.hadiko.de>
To: unlisted-recipients:; (no To-header on input)
Hi!
From: Ryan Kirkpatrick <rkirkpat@nag.cs.colorado.edu>
Subject: Scsi Subsystem Unstablities...
Date: Mon, 16 Aug 1999 07:06:01 -0600 (MDT)
> Recently I have expanded the number of scsi device and scsi
> channels on my file server and while for the most part things have been
> working, there are still a few problems that remain that I have been
> unable to solve.
> I have shortened up the scsi chains as much as possible, and while
> that has reduced the frequency of the problems to some extend, it has not
> removed them. (...)
So it seems to be a hardware-problem.
> (...) I have been able to find is that fast scsi
> chains just can not reallyhandle more than ~5 devices, which need to be
> spaced out on the chain more than I have them.
One of my harddisc crashed (!) because of too long scsi-cables.
I had to low-level-format this drive to get rid of MEDIUM-ERRORS.
Maybe the cable was not really the problem, but this happened after I
added my tape-drive. Now I use the system with the tape-drive and
shorter cables and it is really stable!
The distance between the devices should be at least 10cm. To be in the
limit of 1.5m for my ultra-wide-system (sym53c8xx) I made the cables
on my own. (Where can you buy short cables with more than three
connections?)
> I can not
> verify that the internal termination is turned on for the card (no
> internal devices), as on Alpha there is no opportunity to enter the card's
> BIOS. But I am quite sure that when I last had the card in an intel box,
> that the termination was NOT set to auto.
So it was set to what?
> The only ideas I have to solve this problem is to shorten the
> scsi1 chain by moving the toshiba drives to the primary computer case, and
> remove any connection to the second computer case. Then get another scsi
> (...)
Yes. Try to reduce the devices on one channel. Maybe you could also
decrease the speed on the channels and see what happens.
On my Intelbox I got wired and unrelated problems when I switched
Advanced Power Management in the bios on. The first week I thought
there must be a problem with the scsi-subsystem...
Good luck,
Rob
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