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From: hedrick@topaz.rutgers.edu (Charles Hedrick)
Newsgroups: comp.unix.wizards,comp.unix.questions
Subject: Re: Tuning NFS links
Message-ID: <15529@topaz.rutgers.edu>
Date: Mon, 12-Oct-87 21:11:21 EDT
Article-I.D.: topaz.15529
Posted: Mon Oct 12 21:11:21 1987
Date-Received: Wed, 14-Oct-87 05:32:01 EDT
References: <1482@ist.UUCP>
Organization: Rutgers Univ., New Brunswick, N.J.
Lines: 16
Keywords: NFS performance admin
Xref: mnetor comp.unix.wizards:4865 comp.unix.questions:4511

Re NFS tuning: As far as I know, the default read and write sizes are
fine when they work.  They are available as an option, not for tuning,
but because certain machines and gateways can't handle 6 packets with
minimal spacing.  For those machines, rsize and wsize have to be
specified as having a smaller than normal value.  Generally this
problem is obvious if you have it.  Users see lots of "NFS timeout,
retrying..."  messages.  Similarly, as far as I know the default
timeout values would be OK as long as you are on a single Ethernet, or
on networks connected by high-speed gateways.  The main situation
where you would change them is if your network has something that
would cause longer than normal response times.  You can use "nfsstat"
to see whether you are seeing timeouts and retransmissions.  If so,
try to figure out whether they are due to packets being dropped or
whether you network has delays in it such that packets genuinely take
longer to be acknowledged than the current timeout values. If the
latter, then increase the timeout specifications.