From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Goryachev Subject: Re: Converting 4 disk RAID10 to RAID5 Date: Tue, 27 Oct 2015 17:32:01 +1100 Message-ID: <562F1A61.6010709@websitemanagers.com.au> References: <562D8142.80507@websitemanagers.com.au> <562E345D.5030206@turmel.org> <562EBD58.2040306@websitemanagers.com.au> <562F1789.9080000@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <562F1789.9080000@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Anugraha Sinha , Phil Turmel , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 27/10/15 17:19, Anugraha Sinha wrote: > Dear Adam, > > On 10/27/2015 8:55 AM, Adam Goryachev wrote: >> >> mdadm --grow --bitmap=none /dev/md0 >> root@testraid:~# cat /proc/mdstat >> Personalities : [raid10] [raid0] [raid6] [raid5] [raid4] >> md0 : active raid5 vdf1[4] vdd1[3](S) vde1[2] vdc1[0] >> 2093056 blocks super 1.2 level 5, 512k chunk, algorithm 5 [3/3] >> [UUU] >> >> unused devices: >> >> So, still 3 disk raid5 with one spare, but seems to be insync, so either >> it was really quick (possible since they are small drives) or it didn't >> need to do a sync?? >> >> mdadm --grow --level=5 --raid-devices=4 /dev/md0 >> mdadm: Need to backup 3072K of critical section.. >> >> cat /proc/mdstat >> Personalities : [raid10] [raid0] [raid6] [raid5] [raid4] >> md0 : active raid5 vdf1[4] vdd1[3] vde1[2] vdc1[0] >> 2093056 blocks super 1.2 level 5, 512k chunk, algorithm 5 [4/4] >> [UUUU] >> resync=DELAYED >> >> unused devices: >> >> OK, so now how to make it resync? >> >> Here I'm stuck... >> I've tried: >> mdadm --misc /dev/md0 --action=check >> mdadm --misc /dev/md0 --action=repair >> >> Nothing seems to be happening. >> >> BTW, I had the array mounted during my testing, as ideally that is what >> I will do with the live machine. Worst case scenario (on the live >> machine) I can afford to lose all the data, as it is only an extra >> backup of the other backup machine, but it would mean a few TB's of data >> across a slow WAN.... >> >> Any suggestions on getting this to progress? Did I do something wrong? >> >> Thanks for the suggestion, it certainly looks promising so far. > > Why dont you stop your array once and do something like this? > mdadm --stop /dev/md0 > mdadm --assemble /dev/md0 --run --force --update=resync /dev/vdf1 > /dev/vdd1 /dev/vde1 vdc1 > > This will restart your array with the required raid-level and also > start the resyncing process. I got: mdadm: Failed to restore critical section for reshape, sorry. Possibly you needed to specify the --backup-file Personalities : [raid10] [raid0] [raid6] [raid5] [raid4] md0 : inactive vdd1[3](S) vdf1[4](S) vde1[2](S) vdc1[0](S) 4186112 blocks super 1.2 unused devices: Related dmesg output: [27217.316713] md: md0 stopped. [27217.316727] md: unbind [27217.316732] md: export_rdev(vdc1) [27217.316769] md: unbind [27217.316772] md: export_rdev(vdf1) [27217.316789] md: unbind [27217.316791] md: export_rdev(vdd1) [27217.316806] md: unbind [27217.316809] md: export_rdev(vde1) [27248.819955] md: md0 stopped. [27248.855348] md: bind [27248.868655] md: bind [27248.872681] md: bind [27248.876477] md: bind Any further suggestions? I have no problem with doing the whole process offline, but I assume it will take a lot longer on the live machine (4TB drives), and didn't want to leave it unmounted for a long time. Regards, Adam -- Adam Goryachev Website Managers www.websitemanagers.com.au