Date: Mon, 21 Apr 1997 17:00:09 +0100 From: Alan Judge <Alan.Judge@indigo.ie> To: "Justin T. Gibbs" <gibbs@plutotech.com> Cc: freebsd-scsi@freebsd.org Subject: Re: Vendor specific ASCQ SCSI errors in 2.2-STABLE Message-ID: <199704211600.RAA12615@indigo.ie> In-Reply-To: Message from "Justin T. Gibbs" dated today at 09:47.
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[Thanks for your help.] Justin> Your setup appears to be sound. Using a single ribbon cable Justin> for all of the ultra disks is one of the best ways, according Justin> to an Adaptec study, to ensure correct Ultra SCSI operation. Justin> Hmm. I just had a close look at the system and noticed something I hadn't seen before. One of the ribbon cables (the one on the bus with problems) doesn't end at the fourth connector. Instead the cable goes on an extra 3-4cm and is taped back (not even electrical tape, I think). (This was probably done by our local supplier, who have a tendency to cut corners. I guess they shortened a longer cable.) Could this be the problem? I'm sure the cable stub is not doing the electrical behaviour of the bus any good at all. I'm tempted to remove the cable and trim it to exact length. >> At the moment, I only get the error on sd0 and even there it only >> happens once a day or so. Any ideas on where to start narrowing down >> the problem. Justin> My first hunch would be a bogus connector somewhere in the Justin> system which is putting a large capacitive load on the bus. I Justin> would try changing out a canister at a time with a known good Justin> one. If you can afford to steal a canister from the other Justin> bus, the one that seems to work, that should allow you to be Justin> "scientific" about it. I have a spare cannister, so I can do some tests. Of course, this is a production news server, so shutting down regularly won't make me popular. Given the MTTF though, each test will probably have to take days. Of course, the bogus cable could be the problem. I'll check all the connectors and sockets carefully as well. -- Alan
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