From owner-freebsd-geom@FreeBSD.ORG Tue Jan 9 10:12:22 2007 Return-Path: X-Original-To: freebsd-geom@freebsd.org Delivered-To: freebsd-geom@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 1A33B16A40F for ; Tue, 9 Jan 2007 10:12:22 +0000 (UTC) (envelope-from pjd@garage.freebsd.pl) Received: from mail.garage.freebsd.pl (arm132.internetdsl.tpnet.pl [83.17.198.132]) by mx1.freebsd.org (Postfix) with ESMTP id 9E92413C461 for ; Tue, 9 Jan 2007 10:12:20 +0000 (UTC) (envelope-from pjd@garage.freebsd.pl) Received: by mail.garage.freebsd.pl (Postfix, from userid 65534) id 593E248813; Tue, 9 Jan 2007 11:12:19 +0100 (CET) Received: from localhost (pjd.wheel.pl [10.0.1.1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.garage.freebsd.pl (Postfix) with ESMTP id 1DC2F45CD9; Tue, 9 Jan 2007 11:12:13 +0100 (CET) Date: Tue, 9 Jan 2007 11:11:45 +0100 From: Pawel Jakub Dawidek To: Ahnjoan Amous Message-ID: <20070109101144.GB62430@garage.freebsd.pl> References: <5e575c8a0701081957k43483e1ewf9b27022ae330d8a@mail.gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="kORqDWCi7qDJ0mEj" Content-Disposition: inline In-Reply-To: <5e575c8a0701081957k43483e1ewf9b27022ae330d8a@mail.gmail.com> X-PGP-Key-URL: http://people.freebsd.org/~pjd/pjd.asc X-OS: FreeBSD 7.0-CURRENT i386 User-Agent: mutt-ng/devel-r804 (FreeBSD) X-Spam-Checker-Version: SpamAssassin 3.0.4 (2005-06-05) on mail.garage.freebsd.pl X-Spam-Level: X-Spam-Status: No, score=-5.9 required=3.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham version=3.0.4 Cc: freebsd-geom@freebsd.org Subject: Re: GEOM mirror performance - slow X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Jan 2007 10:12:22 -0000 --kORqDWCi7qDJ0mEj Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jan 08, 2007 at 10:57:14PM -0500, Ahnjoan Amous wrote: > I'm sorry about the double posting, I have switch e-mail clients and > hope that the text is now understandable. >=20 > While deploying 6.1-RELEASE I'm seeing slower than expected speed > using geom mirror. [...] Hard to say, really. It depends on many factors. On my test system: # dd if=3D/dev/zero of=3D/dev/ad4d bs=3D1m count=3D1000 &; dd if=3D/dev/ze= ro of=3D/dev/ad6d bs=3D1m count=3D1000 ad4d: 64.27MB/s ad6d: 61.49MB/s # gmirror label foo ad4d ad6d # dd if=3D/dev/zero of=3D/dev/mirror/foo bs=3D1m count=3D1000 mirror/foo: 61.26MB/s BUT disks can somehow interfere with each other (are on the same ATA channel, etc.). On this system I've this setup: ATA channel 2: Master: ad4 Serial ATA II Slave: ad5 Serial ATA II ATA channel 3: Master: ad6 Serial ATA II Slave: no device present As you saw above, I was using ad4 and ad6, which are on different ATA channels. When I do the same experiment for ad4 and ad5 I see worser results: # dd if=3D/dev/zero of=3D/dev/ad4d bs=3D1m count=3D1000 &; dd if=3D/dev/ze= ro of=3D/dev/ad5d bs=3D1m count=3D1000 ad4d: 59.55MB/s ad5d: 59.31MB/s # gmirror label foo ad4d ad5d # dd if=3D/dev/zero of=3D/dev/mirror/foo bs=3D1m count=3D1000 mirror/foo: 49.03MB/s So not ~40% slowdown as in your case, but still visible slowdown (~20%). --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --kORqDWCi7qDJ0mEj Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (FreeBSD) iD8DBQFFo2pgForvXbEpPzQRAggTAJkB6etmnIJAegMbUgzs3omkJDmfLwCg3/3B St3K0GtfxPlKMNXoDMUBy1s= =5+aw -----END PGP SIGNATURE----- --kORqDWCi7qDJ0mEj--