From mboxrd@z Thu Jan 1 00:00:00 1970 From: keld@keldix.com Subject: Re: Suboptimal raid6 linear read speed Date: Wed, 16 Jan 2013 10:36:51 +0100 Message-ID: <20130116093651.GB1069@www5.open-std.org> References: <20130115123301.GA11948@rabbit.us> <50F55046.7050605@turmel.org> <20130115125507.GA12184@rabbit.us> <20130115170937.GA8831@kevin> <20130115195707.GA30921@www5.open-std.org> <20130116044335.GA10165@kevin> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20130116044335.GA10165@kevin> Sender: linux-raid-owner@vger.kernel.org To: Charles Polisher Cc: Peter Rabbitson , Phil Turmel , linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi Charles It really does not show below which layout you use for RAID10. This is quite important as the different layouts of RAID10 have quite different performance characteristics. The 'far' layout tends to be the fastest. Which command did you use to create the RAID10 array? best regards Keld On Tue, Jan 15, 2013 at 08:43:35PM -0800, Charles Polisher wrote: > keld@keldix.com wrote: > > > Advantage Advantage > > > vs 4 drives vs RAID0 > > > Config Drives Seq write Seq read Write Read Write Read > > > ------ ------ ---------- ---------- ----- ----- ---- ---- > > > RAID0 4 8.1MB/sec 9.3MB/sec 1.00 1.00 1.00 1.00 > > > RAID0 8 16.8MB/sec 15.0MB/sec 2.07 1.61 1.00 1.00 > > > > > > RAID1 4 2.1MB/sec 3.6MB/sec 1.00 1.00 0.25 0.38 > > > RAID1 8 1.6MB/sec 3.6MB/sec 0.76 1.00 0.09 0.24 > > > > > > RAID5 4 16.8MB/sec 9.1MB/sec 1.00 1.00 2.07 0.97 > > > RAID5 8 17.2MB/sec 14.9MB/sec 1.02 1.63 2.12 1.60 > > > > > > RAID6 4 12.6MB/sec 7.9MB/sec 1.00 1.00 1.55 0.84 > > > RAID6 8 14.4MB/sec 14.5MB/sec 1.63 1.83 1.77 1.55 > > > > > > RAID10 4 4.0MB/sec 7.3MB/sec 1.00 1.00 0.49 0.78 > > > RAID10 8 6.3MB/sec 13.4MB/sec 1.57 1.83 0.37 0.89 > > > > > What layout are you using for RAID10? > > Is it Linux MD RAID10? > > # cat /proc/mdstat > Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] > md1 : active raid10 sdi[7] sdh[6] sdg[5] sdf[4] sde[3] sdd[2] sdc[1] sdb[0] > 2118656 blocks 64K chunks 2 near-copies [8/8] [UUUUUUUU] > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html