From mboxrd@z Thu Jan 1 00:00:00 1970 From: Janek Kozicki Subject: Re: Using 2.6.31 liveCD to grow (reshape) raid5 into raid6, then bacck to old kernel? Date: Fri, 13 Nov 2009 10:08:38 +0100 Message-ID: <20091113100838.5ee6fc1d@atak.bl.pg.gda.pl> References: <20091112220351.22a2ad1b@atak.bl.pg.gda.pl> <19196.57969.529323.360914@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <19196.57969.529323.360914@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Neil Brown said: (by the date of Fri, 13 Nov 2009 15:37:05 +1100) > > And so my plan is to get some liveCD with 2.6.31 (or maybe 2.6.32 ?). > > Connect the sixth drive, boot liveCD, perform the migration: > > > > mdadm --add /dev/md2 /dev/sdd3 > > mdadm --grow /dev/md2 --level=raid6 --raid-disks=6 > > > > Then reboot back into linux 2.6.24. > > > > Will this work? > > In principle, yes. > However: > 1/ you need linux 2.6.32 (not yet released). Don't try with 2.6.31 > 2/ you need mdadm 3.1.1 (not yet released). Don't try with 3.1, > which has been withdrawn. > 3/ You need a "--backup-file=/some/file" argument. The /some/file > must be on a different device. > > > > > Will 2.6.24 understand such raid6 ? > > Yes. > mdadm will first convert the RAID5 to a RAID6 in which the Q blocks > are all on the last disk. This is done instantly. > Then mdadm will start and manage a process of re-laying out each > stripe to have the Q blocks rotated around the various devices. > This will take a while, approximately 1 day. Once this is complete, > you can then access the array from 2.6.24. > > NeilBrown Great, thanks a lot! I'm not in such a hurry - I will wait until they are released. -- Janek Kozicki |