From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eli Ben-Shoshan Subject: Accidentally resized array to 9 Date: Fri, 29 Sep 2017 00:23:28 -0400 Message-ID: <0e59cefd-662f-bf77-0c32-49424d504c77@benshoshan.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Content-Language: en-US Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids I need to add another disk to my array (/dev/md128) when I accidentally did an array resize to 9 with the following command: First I add the disk to the array with the following: mdadm --manage /dev/md128 --add /dev/sdl This was a RAID6 with 8 devices. Instead of using --grow with --raid-devices set to 9, I did the following: mdadm --grow /dev/md128 --size 9 This happily returned without any errors so I went to go look at /proc/mdstat and did not see a resize operation going. So I shook my head and read the output of --grow --help and did the right thing which is: mdadm --grow /dev/md128 --raid-devices=9 Right after that everything hit the fan. dmesg reported a lot of filesystem errors. I quickly stopped all processes that were using this device and unmounted the filesystems. I then, stupidly, decided to reboot before looking around. I am now booted and can assemble this array but it seems like there is no data there. Here is the output of --misc --examine: ganon raid # cat md128 /dev/md128: Version : 1.2 Creation Time : Sat Aug 30 22:01:09 2014 Raid Level : raid6 Used Dev Size : unknown Raid Devices : 9 Total Devices : 9 Persistence : Superblock is persistent Update Time : Thu Sep 28 19:44:39 2017 State : clean, Not Started Active Devices : 9 Working Devices : 9 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 512K Name : ganon:ganon - large raid6 (local to host ganon) UUID : 2b3f41d5:ac904000:965be496:dd3ae4ae Events : 84345 Number Major Minor RaidDevice State 0 8 32 0 active sync /dev/sdc 1 8 48 1 active sync /dev/sdd 6 8 128 2 active sync /dev/sdi 3 8 96 3 active sync /dev/sdg 4 8 80 4 active sync /dev/sdf 8 8 160 5 active sync /dev/sdk 7 8 64 6 active sync /dev/sde 9 8 112 7 active sync /dev/sdh 10 8 176 8 active sync /dev/sdl You will note that the "Used Dev Size" is unknown. The output of --misc --examine on each disk looks similar to this: /dev/sdc: Magic : a92b4efc Version : 1.2 Feature Map : 0x0 Array UUID : 2b3f41d5:ac904000:965be496:dd3ae4ae Name : ganon:ganon - large raid6 (local to host ganon) Creation Time : Sat Aug 30 22:01:09 2014 Raid Level : raid6 Raid Devices : 9 Avail Dev Size : 3906767024 (1862.89 GiB 2000.26 GB) Array Size : 0 Used Dev Size : 0 Data Offset : 239616 sectors Super Offset : 8 sectors Unused Space : before=239528 sectors, after=3906789552 sectors State : clean Device UUID : b1bd681a:36849191:b3fdad44:22567d99 Update Time : Thu Sep 28 19:44:39 2017 Bad Block Log : 512 entries available at offset 72 sectors Checksum : bca7b1d5 - correct Events : 84345 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 0 Array State : AAAAAAAAA ('A' == active, '.' == missing, 'R' == replacing) I followed directions to create overlays and I tried to re-create the array with the following: mdadm --create /dev/md150 --assume-clean --metadata=1.2 --data-offset=117M --level=6 --layout=ls --chunk=512 --raid-devices=9 /dev/mapper/sdc /dev/mapper/sdd /dev/mapper/sdi /dev/mapper/sdg /dev/mapper/sdf /dev/mapper/sdk /dev/mapper/sde /dev/mapper/sdh /dev/mapper/sdl while this creates a /dev/md150, it is basically empty. There should be an LVM PV label on this disk but pvck returns: Could not find LVM label on /dev/md150 The output of --misc --examine looks like this with the overlay: /dev/md150: Version : 1.2 Creation Time : Fri Sep 29 00:22:11 2017 Raid Level : raid6 Array Size : 13673762816 (13040.32 GiB 14001.93 GB) Used Dev Size : 1953394688 (1862.90 GiB 2000.28 GB) Raid Devices : 9 Total Devices : 9 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Fri Sep 29 00:22:11 2017 State : clean Active Devices : 9 Working Devices : 9 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 512K Name : ganon:150 (local to host ganon) UUID : 84098bfe:74c1f70c:958a7d8a:ccb2ef74 Events : 0 Number Major Minor RaidDevice State 0 252 11 0 active sync /dev/dm-11 1 252 9 1 active sync /dev/dm-9 2 252 16 2 active sync /dev/dm-16 3 252 17 3 active sync /dev/dm-17 4 252 10 4 active sync /dev/dm-10 5 252 14 5 active sync /dev/dm-14 6 252 12 6 active sync /dev/dm-12 7 252 13 7 active sync /dev/dm-13 8 252 15 8 active sync /dev/dm-15 What do you think? Am I hosed here? Is there any way I can get my data back?