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From: schang@netcom.UUCP (Sehyo Chang)
Newsgroups: comp.sys.dec,comp.unix.ultrix
Subject: Re: DECstation Paging (Swap ?)/Hang problems
Message-ID: <8823@netcom.UUCP>
Date: 10 Mar 90 06:45:40 GMT
References: <1032@crk56.bnr.ca> <1990Mar9.153926.26579@caen.engin.umich.edu>
Organization: NetCom- The Bay Area's Public Access Unix System {408 249-0290 guest}
Lines: 30

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