From mboxrd@z Thu Jan 1 00:00:00 1970 From: jim owens Subject: Re: MD performance options: More =?windows-1252?Q?CPU=92s_or_?= =?windows-1252?Q?more_Hz=92s=3F?= Date: Wed, 04 Nov 2009 10:56:54 -0500 Message-ID: <4AF1A446.700@hp.com> References: <66781b10911040149q165edf1s94a86f179f9af9fc@mail.gmail.com> <4AF18A39.6010404@tmr.com> <66781b10911040634mcdc3c70jec3410c09003fb6c@mail.gmail.com> <4AF1A0B8.2080807@hp.com> <4AF1A1B4.2030405@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4AF1A1B4.2030405@hp.com> Sender: linux-raid-owner@vger.kernel.org To: mark delfman Cc: Bill Davidsen , Linux RAID Mailing List List-Id: linux-raid.ids jim owens wrote: >> So the proper comparison of raid6 software overhead is to >> run the same application writing a fixed large amount of data >> to 4 drives at raid0 and the same 4 drives at raid6. Actually, it is probably better to run the application with 2 X data to raid0 and 1 X data to raid6 so the amount of written disk data is the same. That way the comparison will remove the bus/disk difference caused by sending different amounts of data and: overhead = raid6_time - raid0_time; jim