From mboxrd@z Thu Jan 1 00:00:00 1970 From: maurice Subject: Re: Looking for the best way to do this Date: Fri, 24 Jun 2011 11:11:14 -0600 Message-ID: <4E04C532.2040008@gmail.com> References: <4E00DF31.2020406@gmail.com> <4E03929A.8000503@cdf.toronto.edu> <4E03B8DB.7010607@gmail.com> <4E04B8A9.1050502@cdf.toronto.edu> <4E04BCCF.9000604@gmail.com> <4E04C27E.7040608@cdf.toronto.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4E04C27E.7040608@cdf.toronto.edu> Sender: linux-raid-owner@vger.kernel.org Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 6/24/2011 10:59 AM, Iordan Iordanov wrote: > > On 06/24/11 12:35, maurice wrote: >> Set aside (disconnect) 1 of the existing 2 disks. >> Boot from emergency recovery media, making sure the md version is >> relatively current ( newer than 3.0 ?) >> >> Create the R10 with the other 2 disks ( 1 old and 1 new) with 1 of the 3 >> disks missing. >> I think I have to wipe the superblock on the disk that was formerly part >> of the RAID1 set. > > I think your procedure can be made less risky by making a R10, with > layout f3 with *two* missing disks. Since there are *3* copies in the > R10, there is no problem with having just one "real" disk and two > missing ones. This way, you don't have to live with just one of the R1 > disks and hope it doesn't go bad during the copy operation. > > Then, you copy the data from your old R1 to your new R10 with the two > missing disks. When the data is copied over, you can remove *one* of > the disks from the R1, zero the superblock, and add it to the R10. > When the rebuild is complete, and only then, zero the superblock of > your last R1 disk, and add it to the R10. > > With this mod, your data never really lost redundancy during the > entire procedure (except when you remove the first disk from the R1 > and move it to the R10, but instead of redundancy, you have 2 copies - > one on the R10 and one on the R1 at that point, so it's still > redundant in a way). > > Whether or not you use this revised procedure, write yourself a > step-by-step guide with all the commands (a TO-DO list), and if you > want, you can share it with the list if you're not confident. > Thanks, this makes really good sense, and sounds VERY safe. As for the "TO-DO list" or "recipe" I still lack the skills to produce the syntax. -- Cheers, Maurice Hilarius eMail: /mhilarius@gmail.com/