From owner-freebsd-current@FreeBSD.ORG  Wed Mar 28 13:11:10 2007
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
X-Original-To: freebsd-current@freebsd.org
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 9341B16A404
	for <freebsd-current@freebsd.org>; Wed, 28 Mar 2007 13:11:10 +0000 (UTC)
	(envelope-from uspoerlein@gmail.com)
Received: from nf-out-0910.google.com (nf-out-0910.google.com [64.233.182.191])
	by mx1.freebsd.org (Postfix) with ESMTP id 1865113C4BE
	for <freebsd-current@freebsd.org>; Wed, 28 Mar 2007 13:11:09 +0000 (UTC)
	(envelope-from uspoerlein@gmail.com)
Received: by nf-out-0910.google.com with SMTP id k27so3303166nfc
	for <freebsd-current@freebsd.org>; Wed, 28 Mar 2007 06:11:08 -0700 (PDT)
DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta;
	h=domainkey-signature:received:received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references;
	b=tZ4+2ZLIdrA84MoQf2fcoUTsvEIFXMD6JtImMQ0WICcowukz9MxejEMLDswORhtRC0g8MJsOYAFjZ27zS9Mc01qMbTMUy5SlQVBzipf0iWdFeKvBdJdPNVtAxFMCzj7IL3kX54My6wazsgF7ivSI4ioljPgH2mjzqGZz2CgJL3M=
DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta;
	h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references;
	b=XsCOMvlgyvivtsLue/uESxF136dnDyaqe39pECLSrjoDiVcjBxcNFwXz0Q64abfJQXack6kyTBv00Sqvxz0UQNBIf+UbpDa2UYdmxRgiiepKYx62YqxTB8nOLZzEBtBK147PfqHFUWiaaQ3iDLUNOQlcQk7y9m89/o8Y5nubpeE=
Received: by 10.82.178.11 with SMTP id a11mr18794805buf.1175087467552;
	Wed, 28 Mar 2007 06:11:07 -0700 (PDT)
Received: by 10.82.187.19 with HTTP; Wed, 28 Mar 2007 06:11:07 -0700 (PDT)
Message-ID: <7ad7ddd90703280611p5c0ca4e1y600315551391a813@mail.gmail.com>
Date: Wed, 28 Mar 2007 15:11:07 +0200
From: "Ulrich Spoerlein" <uspoerlein@gmail.com>
To: freebsd-current@freebsd.org
In-Reply-To: <eudfat$g2m$1@sea.gmane.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <7ad7ddd90703280238r5dd3f30ftc1641926ecdf44a8@mail.gmail.com>
	<eudfat$g2m$1@sea.gmane.org>
Subject: Re: NFS write() calls lead to read() calls?
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, 
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 28 Mar 2007 13:11:10 -0000

On 3/28/07, Ivan Voras <ivoras@fer.hr> wrote:
> > The traffic flows like this:
> >
> >  ----->   ----->
> > A        B        C
> >           <-----
>
> Have you tested with a small C program or a script to see if it's the
> rewriting that's causing reads or is it some weird artifact of scp?

I'm not a big user of scp(1), the reason this problem came up is
because Samba has the same problem too. If our Windows Terminal server
(over)writes onto the Samba-Export (which in turn is NFS mounted from
the fileserver) then we get WRITE *and* READ calls. nfsstat -s shows
that the READ column is increasing just as fast/slow as the WRITE
column.

So while I could work around scp anytime (tar|ssh is better in almost
all cases) there is probably no way to work around Samba.

What kind of C program or script did you have in mind? My C-foo is very weak ...

Cheers,
Uli