From owner-freebsd-bugs Tue Oct 7 14:50:07 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id OAA25776 for bugs-outgoing; Tue, 7 Oct 1997 14:50:07 -0700 (PDT) (envelope-from owner-freebsd-bugs) Received: (from gnats@localhost) by hub.freebsd.org (8.8.7/8.8.7) id OAA25767; Tue, 7 Oct 1997 14:50:03 -0700 (PDT) (envelope-from gnats) Date: Tue, 7 Oct 1997 14:50:03 -0700 (PDT) Message-Id: <199710072150.OAA25767@hub.freebsd.org> To: freebsd-bugs Cc: From: Zach Heilig Subject: Re: kern/4684: crash on very heavy disk activity. Reply-To: Zach Heilig Sender: owner-freebsd-bugs@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk The following reply was made to PR kern/4684; it has been noted by GNATS. From: Zach Heilig To: Stefan Esser Cc: FreeBSD-gnats-submit@freebsd.org Subject: Re: kern/4684: crash on very heavy disk activity. Date: Tue, 7 Oct 1997 16:41:35 -0500 I did not see my other reply come over the bugs list [from a while back], so I will paraphrase my other reply... On Sun, Oct 05, 1997 at 11:04:22AM +0200, Stefan Esser wrote: > > ncr0 rev 1 int a irq 11 on pci0:10 > > sd0(ncr0:0:0): M_DISCONNECT received, but datapointer not saved: > > data=701b4 save=e40016b0 goal=e40016d4. > Hmm, the drive disconnected during the probe ... > Does this happen on each boot ? Yes, this happens on every boot. I haven't actually noticed any other problems with sd0 (or sd1) though. > > Here are the last few console messages before the reboot: ... > > This was during both an rm -rf of a large tree on sd2s1e and a cvs checkout > > from the cvs repository I keep on that slice. > The command failed because of lack of agreement on the amount of > data requested. The drive stayed in a data phase, when there was > either no more data to deliver to it, or no more buffer space to > store the data read (depending on whether this happened during a > read or a write). I wonder of there was a bus reset, and the jaz drive responded by just dropping everything it was up to (and returned/wrote incomplete data). > This (together with the disconnect of your UW drive) indicates > there is a SCSI bus problem. SCSI strobe pulses got lost or > duplicated. Just for clarification, I only have 50 pin scsi devices. These devices hang off of a 50 pin port on the scsi card. The card will take ultra-wide devices, but I do not have any. > What's the (total!) length of your SCSI bus ? > (Internal plus external, number of connectors, if any, terminators ?) the devices were on a 38" cable, 5 connectors, 8" between four on one end, and 14" between the single connector and the group. They were in the order card -14"- sd0 -8"- sd1 -8"- sd2 -8"- cd0. cd0 has terminators installed. sd2 has only automatic termination. [ the above are no longer connected ]. sd1 had termination disabled. sd0 has termination and term power disabled. the card only has one setting [and that's for auto termination]. I tried 3 other cables [all with connections for 2 devices]. I re-enabled termination on sd1, and only connected sd0 and sd1. sd0 still disconnected on boot for all three cables. These cables were all around 24" long. I left one of these other cables installed [the one that came with the card]. > Could you try with a much reduced data rate (say 5MHz), just to > make sure it is not caused by the bus cable ? This didn't seem to make any difference. It took longer to induce a crash, but it still did crash. Ok, I'm pretty much convinced this is actually a cable [or device] problem. Unless the ncr driver is sending a reset that is messing up the jaz drive, there doesn't seem to be much on the software side that can fix these things. Even though I don't seem to be having problems with sd0, that is the device that was added not too long ago, and there were no problems at all before that. When I have time, I'll switch the drive to the end and enable all its termination options [and disable the termination on the other devices], and see if that helps any. -- Zach Heilig We know you are a good friend, but we have to charge you for our services just like our other customers. Actually, we don't like charging our friends, but we did a study of our clientel and discovered none of our enemies do business with us. [seen in a lawyers office].