From mboxrd@z Thu Jan 1 00:00:00 1970 From: Haakon Alstadheim Subject: Interrupted reshape -- mangled backup ? Date: Wed, 17 Oct 2012 23:34:26 +0200 Message-ID: <507F2462.2050409@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids I have a Raid5 array with 4 devices that I wanted to see if I could get a better performance out of, so i tried changing the chunk size from 64K to something bigger. (famous last words) . I got into some other trouble and thought I needed a reboot. On reboot I several times managed to mount and specify the device with my backup file during initramfs, but the reshape stopped every time once the system was at initialized. This is under debian sqeeze with a 3.2.0-0.bpo.3-686-pae kernel from backports. I installed mdadm from backports to get the latest version of that as well, and tried rebooting with --freeze-reshape. Suspect that I mixed up my initrd.img-files and started without --freeze-reshape the first time after installing the new mdadm. Now mdadm says it can not find a backup in my backup file. Opening up the backup in emacs, it seems to contain only NULs. Can't be right, can it? I have been mounting the backup under a directory under /dev/, on the assumption that the mount wold survive past the initramfs stage. My bumbling has been happening with a current, correct, /etc/mdadm/mdadm.conf containigng: -------- DEVICE /dev/sdh /dev/sde /dev/sdc /dev/sdd CREATE owner=root group=disk mode=0660 auto=yes HOMEHOST ARRAY /dev/md1 level=raid5 num-devices=4 UUID=583001c4:650dcf0c:404aaa6f:7fc38959 spare-group=main ------- The show-stopper happened with an initramfs and a script in /scripts/local-top/mdadm along the lines of: ------- /sbin/mdadm --assemble -f --backup-file=/dev/bak/md1-backup /dev/md1 --run --auto=yes /dev/sdh /dev/sde /dev/sdc /dev/sdd ------- At times I have also had to use the env-variable MDADM_GROW_ALLOW_OLD=1 Below is the output of mdadm -Evvvvs: -------- /dev/sdh: Magic : a92b4efc Version : 0.91.00 UUID : 583001c4:650dcf0c:404aaa6f:7fc38959 Creation Time : Wed Dec 3 19:45:33 2008 Raid Level : raid5 Used Dev Size : 976762496 (931.51 GiB 1000.20 GB) Array Size : 2930287488 (2794.54 GiB 3000.61 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 1 Reshape pos'n : 2368561152 (2258.84 GiB 2425.41 GB) New Chunksize : 131072 Update Time : Wed Oct 17 02:15:53 2012 State : active Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Checksum : 14da0760 - correct Events : 778795 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 0 8 112 0 active sync /dev/sdh 0 0 8 112 0 active sync /dev/sdh 1 1 8 48 1 active sync /dev/sdd 2 2 8 32 2 active sync /dev/sdc 3 3 8 64 3 active sync /dev/sde /dev/sde: Magic : a92b4efc Version : 0.91.00 UUID : 583001c4:650dcf0c:404aaa6f:7fc38959 Creation Time : Wed Dec 3 19:45:33 2008 Raid Level : raid5 Used Dev Size : 976762496 (931.51 GiB 1000.20 GB) Array Size : 2930287488 (2794.54 GiB 3000.61 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 1 Reshape pos'n : 2368561152 (2258.84 GiB 2425.41 GB) New Chunksize : 131072 Update Time : Wed Oct 17 02:15:53 2012 State : active Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Checksum : 14da0736 - correct Events : 778795 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 3 8 64 3 active sync /dev/sde 0 0 8 112 0 active sync /dev/sdh 1 1 8 48 1 active sync /dev/sdd 2 2 8 32 2 active sync /dev/sdc 3 3 8 64 3 active sync /dev/sde /dev/sdc: Magic : a92b4efc Version : 0.91.00 UUID : 583001c4:650dcf0c:404aaa6f:7fc38959 Creation Time : Wed Dec 3 19:45:33 2008 Raid Level : raid5 Used Dev Size : 976762496 (931.51 GiB 1000.20 GB) Array Size : 2930287488 (2794.54 GiB 3000.61 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 1 Reshape pos'n : 2368561152 (2258.84 GiB 2425.41 GB) New Chunksize : 131072 Update Time : Wed Oct 17 02:15:53 2012 State : active Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Checksum : 14da0714 - correct Events : 778795 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 2 8 32 2 active sync /dev/sdc 0 0 8 112 0 active sync /dev/sdh 1 1 8 48 1 active sync /dev/sdd 2 2 8 32 2 active sync /dev/sdc 3 3 8 64 3 active sync /dev/sde /dev/sdd: Magic : a92b4efc Version : 0.91.00 UUID : 583001c4:650dcf0c:404aaa6f:7fc38959 Creation Time : Wed Dec 3 19:45:33 2008 Raid Level : raid5 Used Dev Size : 976762496 (931.51 GiB 1000.20 GB) Array Size : 2930287488 (2794.54 GiB 3000.61 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 1 Reshape pos'n : 2368561152 (2258.84 GiB 2425.41 GB) New Chunksize : 131072 Update Time : Wed Oct 17 02:15:53 2012 State : active Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Checksum : 14da0722 - correct Events : 778795 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 1 8 48 1 active sync /dev/sdd 0 0 8 112 0 active sync /dev/sdh 1 1 8 48 1 active sync /dev/sdd 2 2 8 32 2 active sync /dev/sdc 3 3 8 64 3 active sync /dev/sde --------------------------- I guess the moral of all this is that if you want to use mdadm you should pay attention and not be in too much of a hurry :-/ . I'm just hoping that I can get my system back. This raid contains my entire system, and will take a LOT of work to recreate. Mail, calendars ... . Backups are a couple of weeks old ...