From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Wed, 28 May 2008 09:39:38 -0700 (PDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.168.28]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m4SGdZEp024004 for ; Wed, 28 May 2008 09:39:35 -0700 Received: from mx1.redhat.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id A2C56BFEC9E for ; Wed, 28 May 2008 09:40:26 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com [66.187.233.31]) by cuda.sgi.com with ESMTP id eCxGEDGqHFWJZjti for ; Wed, 28 May 2008 09:40:26 -0700 (PDT) Message-ID: <483D8AE0.8090606@redhat.com> Date: Wed, 28 May 2008 12:40:00 -0400 From: Chris Snook MIME-Version: 1.0 Subject: Re: Performance Characteristics of All Linux RAIDs (mdadm/bonnie++) References: <95711f160805280934y77ed7d91tec5aeb531bf8013c@mail.gmail.com> In-Reply-To: <95711f160805280934y77ed7d91tec5aeb531bf8013c@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: =?ISO-8859-1?Q?Jens_B=E4ckman?= Cc: Justin Piszcz , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, xfs@oss.sgi.com Jens Bäckman wrote: > On Wed, May 28, 2008 at 10:53 AM, Justin Piszcz wrote: >> Results: >> >> http://home.comcast.net/~jpiszcz/raid/20080528/raid-levels.html >> http://home.comcast.net/~jpiszcz/raid/20080528/raid-levels.txt > > Either the RAID 1 read speed must be wrong, or something is odd in the > Linux implementation. There's six drives that can be used for reading > at the same time, as they contain the very same data. 63MB/s > sequential looks like what you would get from a single drive. The test is a single thread reading one block at a time, so this is not surprising. If you get this doing multi-megabyte readahead, or with several threads, something is very wrong. -- Chris