From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755281AbYE2RCy (ORCPT ); Thu, 29 May 2008 13:02:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751586AbYE2RCm (ORCPT ); Thu, 29 May 2008 13:02:42 -0400 Received: from lucidpixels.com ([75.144.35.66]:57526 "EHLO lucidpixels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751286AbYE2RCl (ORCPT ); Thu, 29 May 2008 13:02:41 -0400 Date: Thu, 29 May 2008 13:02:40 -0400 (EDT) From: Justin Piszcz To: Holger Kiehl cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, xfs@oss.sgi.com Subject: Re: Performance Characteristics of All Linux RAIDs (mdadm/bonnie++) In-Reply-To: Message-ID: References: User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 29 May 2008, Holger Kiehl wrote: > On Wed, 28 May 2008, Justin Piszcz wrote: > >> Hardware: >> >> 1. Utilized (6) 400 gigabyte sata hard drives. >> 2. Everything is on PCI-e (965 chipset & a 2port sata card) >> >> Used the following 'optimizations' for all tests. >> >> # Set read-ahead. >> echo "Setting read-ahead to 64 MiB for /dev/md3" >> blockdev --setra 65536 /dev/md3 >> >> # Set stripe-cache_size for RAID5. >> echo "Setting stripe_cache_size to 16 MiB for /dev/md3" >> echo 16384 > /sys/block/md3/md/stripe_cache_size >> >> # Disable NCQ on all disks. >> echo "Disabling NCQ on all disks..." >> for i in $DISKS >> do >> echo "Disabling NCQ on $i" >> echo 1 > /sys/block/"$i"/device/queue_depth >> done >> >> Software: >> >> Kernel: 2.6.23.1 x86_64 >> Filesystem: XFS >> Mount options: defaults,noatime >> >> Results: >> >> http://home.comcast.net/~jpiszcz/raid/20080528/raid-levels.html >> http://home.comcast.net/~jpiszcz/raid/20080528/raid-levels.txt >> > Why is the Sequential Output (Block) for raid6 165719 and for raid5 only > 86797? I would have thought that raid6 was always a bit slower in writting > due to having to write double amount of parity data. > > Holger > RAID5 (2nd test of 3 averaged runs) & Single disk added: http://home.comcast.net/~jpiszcz/raid/20080528/raid-levels.html