From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: Raid6 write performance Date: Fri, 27 Feb 2009 17:04:52 -0800 Message-ID: <49A88DB4.40008@zytor.com> References: <49742E74.9090502@rabbit.us> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <49742E74.9090502@rabbit.us> Sender: linux-raid-owner@vger.kernel.org To: Peter Rabbitson Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Peter Rabbitson wrote: > Hi, > > I am experimenting with raid6 on 4 drives on 2.6.27.11. The problem I am > having is that no matter what chunk size I use, the write benchmark > always comes out at single drive speed, although I should be seeing > double drive speed (read speed is at near 4x as expected). I have no idea why you "should" be seeing double drive speed. All drives have to be written, so you'd logically see single drive speed. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.