From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ric Wheeler Subject: Re: [PATCH 1/4] md: Factor out RAID6 algorithms into lib/ Date: Fri, 17 Jul 2009 11:58:24 -0400 Message-ID: <4A609FA0.7060404@redhat.com> References: <1247494302.19180.268.camel@macbook.infradead.org> <4A5F6590.9000006@zytor.com> <4A608913.1060808@redhat.com> <4A6096A0.5050501@zytor.com> <4A609A52.7070506@redhat.com> <4A609B72.2010901@zytor.com> <4A609CFA.2060707@redhat.com> <4A609D8D.8050501@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4A609D8D.8050501@zytor.com> Sender: linux-raid-owner@vger.kernel.org To: "H. Peter Anvin" Cc: Dan Williams , David Woodhouse , chris.mason@oracle.com, linux-btrfs@vger.kernel.org, neilb@suse.de, linux-raid@vger.kernel.org List-Id: linux-raid.ids On 07/17/2009 11:49 AM, H. Peter Anvin wrote: > Ric Wheeler wrote: >>> >>> The bottom line is pretty much this: the cost of changing the encoding >>> would appear to outweigh the benefit. I'm not trying to claim the Linux >>> RAID-6 implementation is optimal, but it is simple and appears to be >>> fast enough that the math isn't the bottleneck. >> >> Cost? Thank about how to get free grad student hours testing out >> things that you might or might not want to leverage on down the road :-) >> > > Cost, yes, of changing an on-disk format. > > -hpa > Putting RAID6 behind us, we still might be interested in the other encodings that are in: "A Performance Evaluation and Examination of Open-Source Erasure Coding Libraries For Storage" http://www.cs.utk.edu/~plank/plank/papers/FAST-2009.html since they give us even more flexibility.... ric