From owner-freebsd-questions@FreeBSD.ORG Thu Apr 10 11:01:54 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7C181106564A for ; Thu, 10 Apr 2008 11:01:54 +0000 (UTC) (envelope-from netslists@gmail.com) Received: from fg-out-1718.google.com (fg-out-1718.google.com [72.14.220.155]) by mx1.freebsd.org (Postfix) with ESMTP id 071DA8FC1A for ; Thu, 10 Apr 2008 11:01:52 +0000 (UTC) (envelope-from netslists@gmail.com) Received: by fg-out-1718.google.com with SMTP id 16so3038113fgg.35 for ; Thu, 10 Apr 2008 04:01:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:user-agent:mime-version:to:subject:content-type:content-transfer-encoding; bh=wJvNmGTM1YOJeFH6OtG8XjMhETSju4QHNav0ox6m2DM=; b=qQRkv4Ir8x1T0zkGNdHhhQFDwkA7s9q/5ixfetWcTwP87LJKw95OQ1oLmsRJtGnC+8+GTx8Hg1eDsTqGYE4yiNWjYMUnVkPNxPD9blM+tIWmaJiaIu4woBj9eQl8xWqPl4RkdQh18ItqKA6Xp0JqD8KzEwsYVuOxxrOtqE/6aIQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:subject:content-type:content-transfer-encoding; b=gJvNDcAHu5VFyAGRRIlY5hDwgwJ4MMcE807wXwEimHzjTAeO/JZvAHc9LK0tdCh90TysFTN4Hg5QFo9+JCJaxjCbl6hZSl31hTRMAdRIGI6qQ2MPzvtrJcfxt994MJBGHFkeZbHPhP5nOHm+g/GcafqDK09gXaHx5FpbRgn2qjY= Received: by 10.86.27.19 with SMTP id a19mr2745244fga.43.1207823566490; Thu, 10 Apr 2008 03:32:46 -0700 (PDT) Received: from ?192.168.9.8? ( [91.135.49.10]) by mx.google.com with ESMTPS id u14sm2154582gvf.9.2008.04.10.03.32.43 (version=SSLv3 cipher=RC4-MD5); Thu, 10 Apr 2008 03:32:45 -0700 (PDT) Message-ID: <47FDECC6.7000409@gmail.com> Date: Thu, 10 Apr 2008 12:32:38 +0200 From: Sten Daniel Soersdal User-Agent: Thunderbird 2.0.0.12 (Windows/20080213) MIME-Version: 1.0 To: freebsd-questions Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: RAID-5/Stripe Size and verifying absolute disk stripe access X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Apr 2008 11:01:54 -0000 My problem is aligning reads/writes properly on a 3 disk RAID-5 volume with stripe size of 16384. Since my measurements all show the same relatively low read/write performance on the volume matter which offset i choose on the disklabel "partition" (i've tried with the granularity of a single sector and the results are the same). In FreeBSD 7.0-RELEASE, is there any way to find out a absolute read/write sector location for the beginning of filesystem within a disklabel "partition"? -- Sten Daniel Soersdal