From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tommy Apel Hansen Subject: Re: Suboptimal raid6 linear read speed Date: Wed, 16 Jan 2013 07:37:33 +0100 Message-ID: <1358318253.3022.3.camel@workstation-home> 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="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130116044335.GA10165@kevin> Sender: linux-raid-owner@vger.kernel.org To: Charles Polisher Cc: keld@keldix.com, Peter Rabbitson , Phil Turmel , linux-raid@vger.kernel.org List-Id: linux-raid.ids Hello, 1) you shouldn't use more than 2 drives for RAID1 as performance will be impacted (* at least that's what my own tests show) 2) for RAID10 use "2 far-copies" (-p f2) as that seems to be the most optimal layout /Tommy On Tue, 2013-01-15 at 20:43 -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