From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Subject: Re: [PATCH 00/18] Assorted md patches headed for 2.6.30 Date: Thu, 12 Feb 2009 10:53:05 +0100 Message-ID: <20090212095305.GB11981@rap.rap.dk> References: <20090212031009.23983.14496.stgit@notabene.brown> <20090212081148.GD9439@rap.rap.dk> <12039e3b9172d1a1347b8396cab59f11.squirrel@neil.brown.name> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <12039e3b9172d1a1347b8396cab59f11.squirrel@neil.brown.name> Sender: linux-raid-owner@vger.kernel.org To: NeilBrown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Thu, Feb 12, 2009 at 08:21:12PM +1100, NeilBrown wrote: > On Thu, February 12, 2009 7:11 pm, Keld J=F8rn Simonsen wrote: > > On Thu, Feb 12, 2009 at 02:10:10PM +1100, NeilBrown wrote: > >> Comments and testing very welcome. > > > > I would rather have functionality to convert raid10 to raid5. > > raid1 should be depreciated, as raid10,n2 for all purposes is the s= ame > > but better implementation and performance, and raid10,f2 and raid10= ,o2 > > are even better. Nobody should use raid1 anymore. >=20 > That is a fairly simplistic view. It was also formulated to provoke some thoughts. > raid1 supports --write-mostly and --write-behind which raid10 is unli= kely > ever to support. why? Anyway would it not be possible that this functionality be implemented for raid10,n2? > Certainly in many cases raid10 is just as good or better than raid1 > though. >=20 > Certainly a raid10->raid5 conversion for a 2-drive n2 configuration > is trivial to arrange. Other conversions are less likely to be suppo= rted > as they require significant non-trivial rearrangement of data. Yes, possibly. Some code to grow raid10 would also be desirable. Maybe it is some of the same operations that need to be applied: getting the old data in, have it restructured for the new format, in a safe way, and possibly with the help of an extra disk, or possibly not. It sounds non-trivial to me too. Best regards keld -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html