From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Rabbitson Subject: Re: Raid6 write performance Date: Mon, 19 Jan 2009 13:50:46 +0100 Message-ID: <49747726.1090103@rabbit.us> References: <49742E74.9090502@rabbit.us> <8CB482475EFC01A-17F0-256E@webmail-dx12.sysops.aol.com> <20090119124837.GC23623@rap.rap.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20090119124837.GC23623@rap.rap.dk> Sender: linux-raid-owner@vger.kernel.org To: =?UTF-8?B?S2VsZCBKw7hybiBTaW1vbnNlbg==?= Cc: thomas62186218@aol.com, linux-raid@vger.kernel.org List-Id: linux-raid.ids Keld J=C3=B8rn Simonsen wrote: > On Mon, Jan 19, 2009 at 03:10:01AM -0500, thomas62186218@aol.com wrot= e: >> I tested RAID 5 and RAID 6 with 12 x 15K SAS drives on Ubuntu 8.04=20 >> 64-bit and found their performance to be about the same. I used 256 = K=20 >> chunk size, v1.0 superblocks, stripecachesize of 16384, and readahea= d=20 >> of 65536. >> >> RAID 5 reads: 774 MB/sec >> RAID 5 writes: 585 MB/sec >> >> RAID 6 reads: 742 MB/sec >> RAID 6 writes: 559 MB/sec >> >> My CPU utilization remains under 10% though during writes, and I'm=20 >> wondering what can be done to get write performance closer to read=20 >> performance. I have dual quad-core CPUs so there's plenty of CPU to = go=20 >> around. Any ideas on that front? >=20 > Seems like it is the same equipment that you also did the raid10,f2 > tests for. I think it would be interesting to have a consolidated lis= t > of performance comparisons, when you have completed your tweakings. > Is that part of your plan? >=20 > best regards > keld Not on this machine, but yes, I am planning to do something like this o= n my workstation. I need to get my drives/arrays in order first (got bitten by the 7200.11 fiasco). -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html