[1420] in linux-net channel archive
Re: Strange behaviour with NFS
daemon@ATHENA.MIT.EDU (Ed Carp [khijol SysAdmin])
Thu Nov 23 19:42:22 1995
From: "Ed Carp [khijol SysAdmin]" <khijol!erc@vger.rutgers.edu>
To: khijol!devel.ipacific.net.au!inet:becker@vger.rutgers.edu (Donald Becker)
Date: Thu, 23 Nov 1995 14:37:58 -0600 (CST)
Cc: khijol!vger.rutgers.edu!linux-net@vger.rutgers.edu
In-Reply-To: <199511230050.LAA27582@warp.ipacific.net.au> from "Donald Becker" at Jul 26, 95 00:15:00 am
Reply-To: khijol!netcom.com!ecarp@vger.rutgers.edu
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> >From: joey@finlandia.Infodrom.North.DE (Martin Schulze)
> >Subject: Strange behaviour with NFS
>
> >I found some strange behaviour according to the nfs filesystem in the
> >kernel.
> >
> >Whenever the nfs server isn't reachable the process on the client
> >machine just hangs around, partially in 'D' status which means
> >non-interruptable.
>
> I also encountered this problem today. This bug hung a few nodes on our
> Linux cluster. Luckily one still had a few process slots left to figure to
> do a 'ps'. Here a few notes:
> 1. The processes were in the 'D' disk-wait state. Most were
> swapped out.
> 2. The processes counted toward the load average, but didn't consume
> CPU time. The load average on the still-working machine was >35.
> 3. Doing 'kill -1' and 'kill -9' had no effect. The processes
> didn't even turn into zombies.
>
> The problem apparently started when a few NFS serving nodes were
> unavailable. I assume NFS clients might have timed out. Even when the
> servers were returned to service the processes were still hung.
>
> Donald Becker becker@cesdis.gsfc.nasa.gov
> USRA Center of Excellence in Space Data and Information Sciences.
> Code 930.5, Goddard Space Flight Center, Greenbelt, MD. 20771
> 301-286-0882 http://cesdis.gsfc.nasa.gov/pub/people/becker/whoiam.html
Um, this isn't limited to Linux - Solaris also exhibits this behavior. When one of our NFS
servers dumps the big one, we often have to reboot the clients. Someone suggested that the
mounts be changed from 'hard' to 'soft', but I don't think this would make any difference.
Suggestions welcome...
- --
Ed Carp, N7EKG Ed.Carp@linux.org, ecarp@netcom.com
214/993-3935 voicemail/pager
Finger ecarp@netcom.com for PGP 2.5 public key an88744@anon.penet.fi
Q. What's the trouble with writing an MS-DOS program to emulate Clinton?
A. Figuring out what to do with the other 639K of memory.
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