From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nat Makarevitch Subject: Re: Linux MD RAID 5 Benchmarks Across (3 to 10) 300 Gigabyte Veliciraptors Date: Wed, 11 Jun 2008 17:02:28 +0000 (UTC) Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Justin Piszcz lucidpixels.com> writes: > Ever wonder what kind of speed is possible with 3 disk, 4,5,6,7,8,9,10-disk RAID5s? > Here are the bonnie++ results: > http://home.comcast.net/~jpiszcz/20080607/raid5-benchmarks-3to10-veliciraptors/veliciraptor-raid.html Why does the amount of spindles has nearly no effect on the amount of seeks per second? 3 disks: 713.9 seeks/s (AFAIK the Raptor works at 10000 rpm, getting 230+ seeks/s is astonishing) 10 disks: 705.5 seeks/s (same as 3 disks?!) Did I miss something? Or did you use a very large stripe size (to the point of forbiding the 16 GB file used to span over all spindles?)? Or is it some glitch in the RAID code (I don't think so, on a RAID10 with 10 low-end disk I obtained ~1000 IOPS: http://www.makarevitch.org/rant/raid/#3wmd)?