From owner-freebsd-hackers@FreeBSD.ORG  Mon Jan  8 02:51:58 2007
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
X-Original-To: freebsd-hackers@freebsd.org
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id 53E4716A403
	for <freebsd-hackers@freebsd.org>; Mon,  8 Jan 2007 02:51:58 +0000 (UTC)
	(envelope-from dgilbert@daveg.ca)
Received: from ox.eicat.ca (ox.eicat.ca [66.96.30.35])
	by mx1.freebsd.org (Postfix) with ESMTP id 24C6213C465
	for <freebsd-hackers@freebsd.org>; Mon,  8 Jan 2007 02:51:58 +0000 (UTC)
	(envelope-from dgilbert@daveg.ca)
Received: by ox.eicat.ca (Postfix, from userid 66)
	id 32C73C40B; Sun,  7 Jan 2007 21:34:17 -0500 (EST)
Received: by canoe.dclg.ca (Postfix, from userid 101)
	id 9FD9150840; Sun,  7 Jan 2007 21:34:16 -0500 (EST)
From: David Gilbert <dgilbert@dclg.ca>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-ID: <17825.44456.556954.545497@canoe.dclg.ca>
Date: Sun, 7 Jan 2007 21:34:16 -0500
To: freebsd-hackers@freebsd.org
X-Mailer: VM 7.17 under 21.4 (patch 19) "Constant Variable" XEmacs Lucid
Subject: dump reads more than restore writes?
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 08 Jan 2007 02:51:58 -0000

I've got a command line like the following:

dump -0af - /dev/ad1s1g | restore -rf -

... and I'm watching gstat.  ad1s1g is not mounted.  The disk on which
the restore is running is also quiet (nobody using the disk).

And gstat says that ad1 is consistently reading 31 to 37 megabytes per
second and ad2 (the restore disk) is consistently writing 10 to 13
megabytes per second.  This is over hours --- the figures never catch
up.

So... is gstat wrong?  Is dump reading substantially more than restore
is writing?

Dave.

-- 
============================================================================
|David Gilbert, Independent Contractor.       | Two things can be          |
|Mail:       dave@daveg.ca                    |  equal if and only if they |
|http://daveg.ca                              |   are precisely opposite.  |
=========================================================GLO================