pja@crk56 (Philip Attfield) (03/09/90)
I recall seeing a number of postings in the Dec-89/Jan-90
timeframe relating to paging/swapping and system hang problems on
DECstation 3100's (possibly 2100's as well). I would greatly
appreciate either e-mail or relevant re-posts regarding problem
descriptions (and resolutions), patches etc.
Thanks in advance,
Phil Attfield
BNR Ltd.
PO Box 3511 Station C
Ottawa, Ontario Canada
K1Y 4H7
(613) 763 5391
paul@speedmetal.engin.umich.edu (Paul Killey) (03/09/90)
On the general topic of system hangs on 3100s ... I have a system with 2 maxtor 780M drives, an internal maxtor 200M drive, and a TK-50. My system does hang occasionally with heavy (or the right kind of) disk i/o. I suspect paging i/o does this as well. This isn't the problem where the load average creeps up for a while, and then the system hangs. In my case, I suspect a cabling problem and am waiting for some new cables. At least, I won't look into this more until I get new cables. I think the interaction between the dec bus and some peripherals can be a bit touchy, and there is not a lot of room for error. Minimal reflection, whatever, on the chain of scsi devices, can be a problem. For example, I can hang my machine by doing a dump at any level but level 0. Level 0 works OK. The others fail during the scanning, as the raw file system is seeked and read. But if I change dump to write anything to the screen (either in multi-user or single-user mode) like a . or a carriage return just often enough to slow things down a bit, the level 9 dumps will work. It's always something. But we do have machines that are configured with just an internal maxtor 200M drive hang once in a while too and I suspect either paging i/o or some other glitch in the VM code. 99% of the time, things work fine. --paul "Don't call me baby when she's waiting in the car."
dan@asihub.AUTOSYS.COM (Dan O'Neill) (03/10/90)
Phil,
The Digital Customer Support Center (CSC) will probably have the
information you are looking for. In the US, the number is
1-800-332-8000. Digital may have other support mechanisms in Canada.
The people at the CSC are really quite helpful.
--
Dan O'Neill dan@asihub.AUTOSYS.COM {uunet|ncr-sd}!asihub!dan
Automated Systems, Inc. San Diego R&Dschang@netcom.UUCP (Sehyo Chang) (03/10/90)
In article <1990Mar9.153926.26579@caen.engin.umich.edu> paul@speedmetal.engin.umich.edu (Paul Killey) writes: >On the general topic of system hangs on 3100s ... > >I have a system with 2 maxtor 780M drives, an internal maxtor 200M >drive, and a TK-50. > >My system does hang occasionally with heavy (or the right kind of) disk i/o. >I suspect paging i/o does this as well. This isn't the problem where the >load average creeps up for a while, and then the system hangs. > >In my case, I suspect a cabling problem and am waiting for some new cables. >At least, I won't look into this more until I get new cables. > >I think the interaction between the dec bus and some peripherals can be >a bit touchy, and there is not a lot of room for error. Minimal reflection, >whatever, on the chain of scsi devices, can be a problem. > >paging i/o or some other glitch in the VM code. 99% of the time, things work >fine. > >--paul We were able to consistenly reproduce this "hanging" problem. It appears when there are frequent swapping which cause VM to dump core which in turn *may* repeatly hang system. This is very bad because you need swapping in order to do large work -- Sehyo Chang schang@netcom.uucp Ascent Logic Corp. (408)943-0630