From owner-freebsd-stable@FreeBSD.ORG Sun Mar 30 15:13:36 2003 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CE7EC37B405 for ; Sun, 30 Mar 2003 15:13:36 -0800 (PST) Received: from wantadilla.lemis.com (wantadilla.lemis.com [192.109.197.80]) by mx1.FreeBSD.org (Postfix) with ESMTP id DAC7B43FB1 for ; Sun, 30 Mar 2003 15:13:34 -0800 (PST) (envelope-from grog@lemis.com) Received: by wantadilla.lemis.com (Postfix, from userid 1004) id E3D7B51A6F; Mon, 31 Mar 2003 08:43:32 +0930 (CST) Date: Mon, 31 Mar 2003 08:43:32 +0930 From: Greg 'groggy' Lehey To: Dag-Erling =?iso-8859-1?Q?Sm=F8rgrav?= Message-ID: <20030330231332.GE1861@wantadilla.lemis.com> References: <20030330125138.K23911@leelou.in.tern> <20030330081831.5c4e317e.fearow@attbi.com> <20030330163238.X23911@leelou.in.tern> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="HeFlAV5LIbMFYYuh" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4i Organization: The FreeBSD Project Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-418-838-708 WWW-Home-Page: http://www.FreeBSD.org/ X-PGP-Fingerprint: 9A1B 8202 BCCE B846 F92F 09AC 22E6 F290 507A 4223 cc: freebsd-stable@freebsd.org cc: Lukas Ertl Subject: Re: vinum performance X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Mar 2003 23:13:41 -0000 --HeFlAV5LIbMFYYuh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sunday, 30 March 2003 at 18:10:07 +0200, Dag-Erling Smrgrav wrote: > Lukas Ertl writes: >> I'm currently testing with prime stripe sizes, but it doesn't seem to >> help. I additionally added "options AHC_ALLOW_MEMIO" to the kernel, and it >> has raised write performance in the single-disk case (although I'm not >> happy with that one either; I expected a disk on a U160 controller to pump >> out more than ~65MB/s). > > Does the data sheet for your disk indicate that it can in fact write > much faster than that? The speed at which data is actually written > to the media is much lower than the bus speed - the bus speed *has* > to be higher to accomodate multiple devices. You're touching on one of the real issues here. For optimum transfers, a plex needs large stripes. If you're only doing one transfer at a time (like bonnie does), you'll just pick on individual disks alternately, so the performance can't be much better than a single disk. Do a large number of simultaneous transfers and it will be a different story. Greg -- See complete headers for address and phone numbers --HeFlAV5LIbMFYYuh Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.0 (FreeBSD) iD8DBQE+h3ocIubykFB6QiMRAsa1AKCv2Y3zu2R0Jep4/738J9nQAM0ZqACfW5Mo GwTvsiI6KuaQaWPxIx2Jj2I= =PgcI -----END PGP SIGNATURE----- --HeFlAV5LIbMFYYuh--