From mboxrd@z Thu Jan 1 00:00:00 1970 From: Piergiorgio Sartor Subject: Re: RAID-10 unbalanced reads Date: Tue, 24 Feb 2009 00:24:15 +0100 Message-ID: <20090223232415.GA24493@lazy.lzy> References: <20090209202728.GA11996@lazy.lzy> <20090209231138.GB13450@rap.rap.dk> <20090223221532.GA23542@lazy.lzy> <20090223225202.GA28505@rap.rap.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20090223225202.GA28505@rap.rap.dk> Sender: linux-raid-owner@vger.kernel.org To: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Cc: Piergiorgio Sartor , linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi, > You think the sdb2 read rate of 151 blks/s vs sda2 63 blks/s is strange? > Well, it does look strange. OTOH the tps is > > sdb2 5.93 > sda2 5.42 > > Which is not so big a difference. Also the whole RAID tps somehow matches the (sum of the) single devices. > what is sdb1 and sda1 used for? the fugures there seems even stranger. > It also looks strnge that the sdb disk is the slower about 80 MB/s > while sda is around 110 MB/s - and then sdb produces more than sda... The first partion (sda1, sdb1) is the /boot, around 100MB, the rest (sda2, sdb2) is the LVM physical volume, around 320GB. Also this looks strange: Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn sdb2 4.98 109.30 64.28 1444432 849528 md1 10.45 95.23 51.27 1258536 677608 sdb2 has more reads than the whole RAID it belongs, but tps are OK... The only thing that *could* do something on the raw devices is "smartd", I cannot think anything else. Maybe I will disable it, for now... bye, -- piergiorgio