From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: RAID-6 polynomial Date: Thu, 22 Apr 2010 22:43:57 -0700 Message-ID: <4BD1339D.3040506@zytor.com> References: <4BCF9FB2.9060505@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Tirumala Reddy Marri Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 04/22/2010 09:14 PM, Tirumala Reddy Marri wrote: > > Is there a reason for hard coding 0x11d as polynomial ? The problem I > ran into was when I was trying disk fail test there was issue in > recovering the data. Then it turned out to be ADMA was using polynomial > 0x14d and SW algorithm was using 0x11d. This was because syndrome > calculated using DMA engine and recovery done using SW api. > Yes, it would mean the on-disk format would be incompatible otherwise. Everyone needs to use the same polynomial. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.