From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750820AbWATKyR (ORCPT ); Fri, 20 Jan 2006 05:54:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750816AbWATKyR (ORCPT ); Fri, 20 Jan 2006 05:54:17 -0500 Received: from gate.in-addr.de ([212.8.193.158]:50116 "EHLO mx.in-addr.de") by vger.kernel.org with ESMTP id S1750812AbWATKyQ (ORCPT ); Fri, 20 Jan 2006 05:54:16 -0500 Date: Fri, 20 Jan 2006 11:53:06 +0100 From: Lars Marowsky-Bree To: Phillip Susi , Neil Brown Cc: Jan Engelhardt , "Lincoln Dale (ltd)" , Michael Tokarev , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, "Steinar H. Gunderson" Subject: Re: [PATCH 000 of 5] md: Introduction Message-ID: <20060120105306.GY22163@marowsky-bree.de> References: <26A66BC731DAB741837AF6B2E29C1017D47EA0@xmb-hkg-413.apac.cisco.com> <17358.52476.290687.858954@cse.unsw.edu.au> <43D00FFA.1040401@cfl.rr.com> <17360.5011.975665.371008@cse.unsw.edu.au> <43D02033.4070008@cfl.rr.com> <17360.9233.215291.380922@cse.unsw.edu.au> <43D04828.8010107@cfl.rr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <43D04828.8010107@cfl.rr.com> X-Ctuhulu: HASTUR User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 2006-01-19T21:17:12, Phillip Susi wrote: > I am under the impression that dm is simpler/cleaner than md. That > impression very well may be wrong, but if it is simpler, then that's a > good thing. That impression is wrong in that general form. Both have advantages and disadvantages. I've been an advocate of seeing both of them merged, mostly because I think it would be beneficial if they'd share the same interface to user-space to make the tools easier to write and maintain. However, rewriting the RAID personalities for DM is a thing only a fool would do without really good cause. Sure, everybody can write a RAID5/RAID6 parity algorithm. But getting the failure/edge cases stable is not trivial and requires years of maturing. Which is why I think gentle evolution of both source bases towards some common API (for example) is much preferable to reinventing one within the other. Oversimplifying to "dm is better than md" is just stupid. Sincerely, Lars Marowsky-Brée -- High Availability & Clustering SUSE Labs, Research and Development SUSE LINUX Products GmbH - A Novell Business -- Charles Darwin "Ignorance more frequently begets confidence than does knowledge"