From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marco Subject: Re: raid1 performance Date: Sat, 31 Jul 2010 15:21:40 +0000 (GMT) Message-ID: <13942.81514.qm@web28516.mail.ukl.yahoo.com> References: <443220.14357.qm@web28508.mail.ukl.yahoo.com> <20100725211926.7547c12e@natsu> <23123.42111.qm@web28503.mail.ukl.yahoo.com> <20100726210324.6a4077e6@notabene> <379853.84515.qm@web28502.mail.ukl.yahoo.com> <20100728082358.4abc6868@notabene> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <20100728082358.4abc6868@notabene> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids >> sda 84.02 >> sdb 113,69 >> md2 8,01 >> >> md2 and his meber have a very different ratio.... > >Strange isn't it. And the ratios are the other-way-around to what I get. >I don't currently understand why ... but it might not be at all relevant to >the speed difference. Hi, i did some test on a different machine with centos 5.5 and ICH10 disk controller. On this machine i have no performance issue: hdparm -t return the same value (about 107 MB/s) on both /dev/md0 and its members I measured the "ratio" and i obtained 8.02 for md0 and 505 for meber disk. I it seems that the "raito" is not so relevant for this issue. What do you think ? In this case the md device was not mounted. I also tried several different io scheduler whithout noting any effect on sequential read eprformance. Marco