Xref: utzoo comp.sys.sequent:406 comp.protocols.nfs:428
Path: utzoo!attcan!uunet!cs.utexas.edu!mailrus!ames!decwrl!pyramid!csg
From: csg@pyramid.pyramid.com (Carl S. Gutekunst)
Newsgroups: comp.sys.sequent,comp.protocols.nfs
Subject: Re: Problems using Sequent Symmetry as NFS server?
Message-ID: <85680@pyramid.pyramid.com>
Date: 27 Sep 89 23:20:29 GMT
References: <3022@orion.cf.uci.edu>
Reply-To: csg@pyramid.pyramid.com (Carl S. Gutekunst)
Organization: Pyramid Technology Corp., Mountain View, CA
Lines: 32

In article <3022@orion.cf.uci.edu> iglesias@orion.oac.uci.edu (Mike Iglesias) writes:
>On occasion (more often than we'd like), the client systems will start
>printing messages about the NFS server not responding.  This goes on
>for about 45 seconds or so, and then the client can talk to the server
>again.  We don't see this on Suns that are on the same subnet as the
>Sequent server, which could indicate it's a network problem.

That's the key that tells you it's a routing problem. You can easily verify
this by attempting an rlogin at the same time as NFS is having trouble. If
the rlogin just sits there, then routing is the problem.

Whether it's something you can easily fix is less clear. Older versions of
routed, the route daemon, are known for going catatonic, spitting up, and
other rude behavior that can result in networks temporarilly being separated
from each other; and last I knew, Dynix was still using the 4.2BSD routed.
Also SunOS older than, oh, 3.4 or so.

Figuring out who dropped what involves using netstat -r to determine which
routes are vanishing at which nodes. If you can find a TCP/IP wizard to watch
the netstat output while you are having troubles, you may be able to find a
single node that is eating routes because of some trivial configuration
problem. More often than not, it will be the gateway machine itself that is
having problems.

The draconion solution is to use static routing, instead of dynamic. You then
use the route(8) command to add the routes by hand in /etc/rc.boot, and do
*not* start routed(8). It actually works very well if your network is small
and you don't change the topology very often. If it's the gateway that is
dropping routes, then you use static routing on the gateway, and dynamic on
all other machines.