Path: utzoo!attcan!uunet!mailrus!purdue!decwrl!sgi!arisia!cdp!steve From: steve@cdp.UUCP Newsgroups: comp.unix.i386 Subject: Disks Hang Under 2.0.2 SCSI Message-ID: <654400003@cdp> Date: 12 Dec 89 00:58:00 GMT Lines: 85 Nf-ID: #N:cdp:654400003:000:2832 Nf-From: cdp.UUCP!steve Dec 11 16:58:00 1989 SUMMARY -- README ------- We have been experiencing regular crashes running under Interactive 2.0.2 with 3 SCSI disks on an aha1542a. Later in this message is a script which crashes our machine. The purpose of this message is to find other people who are willing to try to replicate these crashes on various machines. I encourage folks to try out the script, even if they do not have our exact hardware configuration. This will help us to better understand the whether the problem lies in hardware or in 2.0.2. DETAILS ------- The symptom of the crashes is that all processes continue to run, but any process that goes for the disk hangs. So, getty prints the login prompt, and accepts a name at login:, but when it goes to spawn login, the exec hangs the system. Switch to a different virtual console, and repeat the same thing. emacs works fine until it tries to auto-save, open a file, etc... The crashes occurs intermittently -- about once a day on our machine that averages 20 users at a time and is up 24 hours a day. On an alternate machine, I have developed a little program that can reliably crash the machine with 3 or more disks within about 2 seconds of invocation. The program looks like this : ----------------------------------------------------------- : # crashix.sh # # hangs i/386 2.0.2 SCSI driver within 2 seconds. # Assume root partition on /dev/dsk/0s1, other # partitions on /dev/dsk/1s3 and /dev/dsk/2s3. # sync sync dd if=/dev/dsk/0s1 bs=128k >/dev/null & dd if=/dev/dsk/1s3 bs=128k >/dev/null & dd if=/dev/dsk/2s3 bs=128k >/dev/null & ---------------------------------------------------------- Notes : o It is important to have all of the dd's in the background, so that they all have the same priority. The occurence of crashes is related disk use intensity; having processes with lower priority reduces the disk use intensity and crash frequency. o You may have different partitioning on your disks. Change the device names to suit your configuration. Try it with 2 3 or 4 disks. o Our hardware configuration is : - Mylex MI-386/20 motherboard, 8MB RAM on board. - aha1542a SCSI host adapter 4 CDC 94161 150MB SCSI disks 1 Archive 2150s "VIPER" cartridge drive - a hercules card. o I have tried crashix.sh with three other motherboards (two based on recent Chips & Technologies chip sets), and the behaviour is the same (crash within 2 seconds). Support at interactive OEM division has returned calls, but skeptical that this is software-related. Thanks for your help. If people that test their machines keep me informed, I will post the results to the net. Steve Fram Chief Programmer Community Data Processing (CdP) {hplabs, pyramid, ...}!cdp!steve (415)-322-9069