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