Unmountable volume - HELP!

BTRFS
1

Hi, if anyone is able to help with a rather large (34TB of data on it)
BTRFS RAID 6 I would be very grateful (pastebins below) - at this
point I am only interested in recovery since I am obviously switching
to RAID 1 once/if I get my data back.

Many thanks in advance

Chris

Linux rockstor 4.6.0-1.el7.elrepo.x86_64 #1 SMP Mon May 16 10:54:52
EDT 2016 x86_64 x86_64 x86_64 GNU/Linux

btrfs-progs v4.6

Label: ‘rockstor_rockstor’ uuid: af53ae5b-419e-4246-9366-611b710eead6
Total devices 1 FS bytes used 1.50GiB
devid 1 size 100.12GiB used 4.02GiB path /dev/sda3

This one is fine:

Label: ‘2’ uuid: 815fa02f-4871-4703-9208-03ccc48cc816
Total devices 9 FS bytes used 38.98TiB
devid 1 size 7.28TiB used 6.27TiB path /dev/sdg
devid 2 size 7.28TiB used 6.27TiB path /dev/sdh
devid 3 size 7.28TiB used 6.27TiB path /dev/sdi
devid 4 size 7.28TiB used 6.27TiB path /dev/sdj
devid 5 size 7.28TiB used 6.27TiB path /dev/sdc
devid 6 size 7.28TiB used 6.27TiB path /dev/sdd
devid 7 size 7.28TiB used 6.27TiB path /dev/sde
devid 8 size 7.28TiB used 6.27TiB path /dev/sdf
devid 11 size 7.28TiB used 6.27TiB path /dev/sdb

this one wont mount:

Label: ‘1’ uuid: ba29167b-e0cf-4029-92a4-f12a97f7e472
Total devices 11 FS bytes used 34.23TiB
devid 2 size 5.46TiB used 3.82TiB path /dev/sdk
devid 3 size 5.46TiB used 3.82TiB path /dev/sdl
devid 4 size 5.46TiB used 3.82TiB path /dev/sdm
devid 5 size 5.46TiB used 3.82TiB path /dev/sdn
devid 6 size 5.46TiB used 3.82TiB path /dev/sdo
devid 7 size 5.46TiB used 3.82TiB path /dev/sdp
devid 8 size 5.46TiB used 3.82TiB path /dev/sdq
devid 9 size 5.46TiB used 3.82TiB path /dev/sdr
devid 10 size 5.46TiB used 3.82TiB path /dev/sds
devid 11 size 5.46TiB used 3.82TiB path /dev/sdt
devid 12 size 5.46TiB used 3.82TiB path /dev/sdu

full dmesg : http://pastebin.com/xgwfkGum

trying to mount: http://pastebin.com/DSfHsda6

btrfs restore: http://pastebin.com/EAuPW1pg

btrfs check: http://pastebin.com/FjM7amEv

finding roots: http://pastebin.com/SBsn12d9

2

@McFaul Hello again.
Just linking to your duplicate post on linux-btrfs mailing list for context.
Dated 6th August: https://mail-archive.com/linux-btrfs@vger.kernel.org/msg56385.html

3

Oh, great thanks, i didnt realise that the mailing list showed up on the web like that (im very new to this!)

4

there are a couple of data recovery software which claim to be able to work with BTRFS, so i may investigate those if they are read-only (i do have space to copy the files off the pool onto other storage if i can get to them)

5

I would say your best bet is to follow what ever advise you get on the linux-btrfs mailing list as that is the canonical knowledge of such things. Have you already looked into the restore function built into btrfs-progs?. My understanding is that it is intended for this very case, ie data retrieval when you have space to copy off the data.
https://btrfs.wiki.kernel.org/index.php/Restore

Hope that helps.

6

as in my original post :frowning:

7

@McFaul Are yes sorry, limited time here I’m afraid.

8

No problem, I do appreciate all the help, it’s just that I’ve already tried pretty much everything relatively easy

Hopefulky one of the devs will take pity on me