From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wols Lists Subject: Re: Is it possible to break one full RAID-1 to two degraded RAID-1? Date: Fri, 7 Feb 2020 09:27:56 +0000 Message-ID: <5E3D2D9C.8020908@youngman.org.uk> References: <1120831b-13e6-6a5d-8908-ee6a312e7302@gmail.com> <2c4fedff-a1c9-6ca3-5385-72b542a4a0b4@gmail.com> <551449ed-49f9-e567-09d3-981f4cf9eea9@thelounge.net> <5E32855D.3020906@youngman.org.uk> <0c70c04f-d8d0-0c44-e603-46c101b21cc1@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <0c70c04f-d8d0-0c44-e603-46c101b21cc1@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Ram Ramesh , Reindl Harald , Linux Raid List-Id: linux-raid.ids On 07/02/20 07:02, Ram Ramesh wrote: > I got no response on this and want to take a shot before going the > backup way. > > Assuming (hda1 and hdb1 in raid1 md0) Will the following work? > > 1. Fail and remove hdb1 > 2. Create new RAID1 md1 with hdb1 and missing > 3. dd md0 onto md1 I wouldn't bother with any of the above. Just shut down and physically remove a LIVE disk. That now is your backup. In fact, this might be a good excuse to get a 3rd disk and either go raid 5 or use it for backups. > 4. Make both bootable. (I suppose I need to change UUID of md1 > partitions. I suppose that is easy) Yes it's easy. Yes it should have been done a LOOONG time ago. > 5. Boot both and double check They'll be degraded, so you might have to do a forced assembly to make them run ... > 6. Now upgrade md0 without fear. > 7. Boot and test the new system for a couple of days to make sure > everything is fine. > 8. If that fails, delete md0, and add hda1 to md1. If not delete md1 > and add hdb1 to md0 Yup. > > Regards > Ramesh > Cheers, Wol