From owner-freebsd-current@FreeBSD.ORG Mon Oct 25 21:40:09 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 716C316A4CE; Mon, 25 Oct 2004 21:40:09 +0000 (GMT) Received: from vhost109.his.com (vhost109.his.com [216.194.225.101]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2678343D39; Mon, 25 Oct 2004 21:40:09 +0000 (GMT) (envelope-from brad@stop.mail-abuse.org) Received: from [10.0.1.3] (localhost.his.com [127.0.0.1]) by vhost109.his.com (8.12.11/8.12.3) with ESMTP id i9PLe67k097225; Mon, 25 Oct 2004 17:40:07 -0400 (EDT) (envelope-from brad@stop.mail-abuse.org) Mime-Version: 1.0 X-Sender: bs663385@127.0.0.1 Message-Id: In-Reply-To: <417D6F4C.9000404@freebsd.org> References: <14479.1098695558@critter.freebsd.dk><417D25E8.6080804@ng.fadesa .es> <200410251928.01536.victor@alf.dyndns.ws><200410251837.58257.Thoma s.Sparrev ohn@btinternet.com><417D3F12.20302@DeepCore.dk> <417D40A1.9030802@ng.fadesa.es><417D45F1.9090504@freebsd.org> <77F3FD4D-26BE-11D9-9A2F-003065ABFD92@mac.com><417D58B6.5030509@fr eebsd.org > <417D65F1.2040809@freebsd.org> <417D6F4C.9000404@freebsd.org> Date: Mon, 25 Oct 2004 23:39:57 +0200 To: Scott Long From: Brad Knowles Content-Type: text/plain; charset="us-ascii" ; format="flowed" cc: fandino@ng.fadesa.es cc: Charles Swiger cc: freebsd-current@freebsd.org Subject: Re: FreeBSD 5.3b7and poor ata performance X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Oct 2004 21:40:09 -0000 At 3:25 PM -0600 2004-10-25, Scott Long wrote: > But as was said, there is always > a performance vs. reliability tradeoff. Well, more like "Pick two: performance, reliability, price" ;) > And when you are talking about > RAID-10 with a bunch of disks, you will indeed start seeing bottlenecks > in the bus. When you're talking about using a lot of disks, that's going to be true for any disk subsystem that you're trying to get a lot of performance out of. The old rule was that if you had more than four disks per channel, you were probably hitting saturation. I don't know if that specific rule-of-thumb is still valid, but I'd be surprised if disk controller performance hasn't roughly kept up with disk performance over time. -- Brad Knowles, "Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety." -- Benjamin Franklin (1706-1790), reply of the Pennsylvania Assembly to the Governor, November 11, 1755 SAGE member since 1995. See for more info.