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From: lm@slovax.Eng.Sun.COM (Larry McVoy)
Newsgroups: comp.protocols.nfs
Subject: Re: NFS performance
Message-ID: <623@appserv.Eng.Sun.COM>
Date: 13 Jun 91 04:05:14 GMT
References: <1388@appli.se>
Sender: news@appserv.Eng.Sun.COM
Organization: Sun Microsystems, Mt. View, CA.
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niklas@appli.se (Niklas Hallqvist) writes:
> Truely enough, I got only 25k/sec on transfer from a SCO Unix to an ISC 2.0.2.
> The other way around it was 200k/sec, that's an order of magnitude involved here!

I suspect you are running into the following NFSism: all writes to an NFS
server are turned into sync writes on the server (like you opened with
O_SYNC).  This is very slow, large transfers can be 3x or more slower on
writes than reads.

The reason for this has to do with NFS' stateless nature - it can't ACK
the write until the data is safe; otherwise the server could crash and the
client would lose data.

> What startles me is that I think Lachman has written the NFS implementation for
> both SCO and ISC, but that might be wrong.  

Lachman didn't write either - they ported them.
---
Larry McVoy, Sun Microsystems     (415) 336-7627       ...!sun!lm or lm@sun.com