From owner-freebsd-stable@FreeBSD.ORG Sun Mar 30 08:10:11 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 D7A9F37B401 for ; Sun, 30 Mar 2003 08:10:11 -0800 (PST) Received: from flood.ping.uio.no (flood.ping.uio.no [129.240.78.31]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8E01043FA3 for ; Sun, 30 Mar 2003 08:10:10 -0800 (PST) (envelope-from des@ofug.org) Received: by flood.ping.uio.no (Postfix, from userid 2602) id B781C5308; Sun, 30 Mar 2003 18:10:08 +0200 (CEST) X-URL: http://www.ofug.org/~des/ X-Disclaimer: The views expressed in this message do not necessarily coincide with those of any organisation or company with which I am or have been affiliated. To: Lukas Ertl From: des@ofug.org (Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?=) Date: Sun, 30 Mar 2003 18:10:07 +0200 In-Reply-To: <20030330163238.X23911@leelou.in.tern> (Lukas Ertl's message of "Sun, 30 Mar 2003 16:38:15 +0200 (CEST)") Message-ID: User-Agent: Gnus/5.090015 (Oort Gnus v0.15) Emacs/21.2 References: <20030330125138.K23911@leelou.in.tern> <20030330081831.5c4e317e.fearow@attbi.com> <20030330163238.X23911@leelou.in.tern> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable cc: freebsd-stable@freebsd.org 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 16:10:42 -0000 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. For instance, the "internal formatted transfer rate" for a recent 73GB Seagate Cheetah varies between 38.4 and 63.9 MB/s (depending on how far out from the spindle you're writing). You won't see higher average transfer speeds than that unless the data you're writing fits entirely within the disk's on-board cache. DES --=20 Dag-Erling Sm=F8rgrav - des@ofug.org