Hi all, I have been a happy BTRFS user for quite some time. But now I'm facing a potential ~45TB dataloss... :-( I hope someone can help!
I have Server A and Server B. Both having a 20-devices BTRFS RAID6 filesystem. Because of known RAID5/6 risks, Server B was a backup of Server A. After applying updates to server B and reboot, the FS would not mount anymore. Because it was "just" a backup. I decided to recreate the FS and perform a new backup. Later, I discovered that the FS was not broken, but I faced this issue: https://patchwork.kernel.org/patch/10694997/ Anyway, the FS was already recreated, so I needed to do a new backup. During the backup (using rsync -vah), Server A (the source) encountered an I/O error and my rsync failed. In an attempt to "quick fix" the issue, I rebooted Server A after which the FS would not mount anymore. I documented what I have tried, below. I have not yet tried anything except what is shown, because I am afraid of causing more harm to the FS. I hope somebody here can give me advice on how to (hopefully) retrieve my data... Thanks in advance! ========================================== [root@cornelis ~]# btrfs fi show Label: 'cornelis-btrfs' uuid: ac643516-670e-40f3-aa4c-f329fc3795fd Total devices 1 FS bytes used 463.92GiB devid 1 size 800.00GiB used 493.02GiB path /dev/mapper/cornelis-cornelis--btrfs Label: 'data' uuid: 4c66fa8b-8fc6-4bba-9d83-02a2a1d69ad5 Total devices 20 FS bytes used 44.85TiB devid 1 size 3.64TiB used 3.64TiB path /dev/sdn2 devid 2 size 3.64TiB used 3.64TiB path /dev/sdp2 devid 3 size 3.64TiB used 3.64TiB path /dev/sdu2 devid 4 size 3.64TiB used 3.64TiB path /dev/sdx2 devid 5 size 3.64TiB used 3.64TiB path /dev/sdh2 devid 6 size 3.64TiB used 3.64TiB path /dev/sdg2 devid 7 size 3.64TiB used 3.64TiB path /dev/sdm2 devid 8 size 3.64TiB used 3.64TiB path /dev/sdw2 devid 9 size 3.64TiB used 3.64TiB path /dev/sdj2 devid 10 size 3.64TiB used 3.64TiB path /dev/sdt2 devid 11 size 3.64TiB used 3.64TiB path /dev/sdk2 devid 12 size 3.64TiB used 3.64TiB path /dev/sdq2 devid 13 size 3.64TiB used 3.64TiB path /dev/sds2 devid 14 size 3.64TiB used 3.64TiB path /dev/sdf2 devid 15 size 7.28TiB used 588.80GiB path /dev/sdr2 devid 16 size 7.28TiB used 588.80GiB path /dev/sdo2 devid 17 size 7.28TiB used 588.80GiB path /dev/sdv2 devid 18 size 7.28TiB used 588.80GiB path /dev/sdi2 devid 19 size 7.28TiB used 588.80GiB path /dev/sdl2 devid 20 size 7.28TiB used 588.80GiB path /dev/sde2 [root@cornelis ~]# mount /dev/sdn2 /mnt/data mount: /mnt/data: wrong fs type, bad option, bad superblock on /dev/sdn2, missing codepage or helper program, or other error. [root@cornelis ~]# btrfs check /dev/sdn2 Opening filesystem to check... parent transid verify failed on 46451963543552 wanted 114401 found 114173 parent transid verify failed on 46451963543552 wanted 114401 found 114173 checksum verify failed on 46451963543552 found A8F2A769 wanted 4C111ADF checksum verify failed on 46451963543552 found 32153BE8 wanted 8B07ABE4 checksum verify failed on 46451963543552 found 32153BE8 wanted 8B07ABE4 bad tree block 46451963543552, bytenr mismatch, want=46451963543552, have=75208089814272 Couldn't read tree root ERROR: cannot open file system [root@cornelis ~]# btrfs restore /dev/sdn2 /mnt/data/ parent transid verify failed on 46451963543552 wanted 114401 found 114173 parent transid verify failed on 46451963543552 wanted 114401 found 114173 checksum verify failed on 46451963543552 found A8F2A769 wanted 4C111ADF checksum verify failed on 46451963543552 found 32153BE8 wanted 8B07ABE4 checksum verify failed on 46451963543552 found 32153BE8 wanted 8B07ABE4 bad tree block 46451963543552, bytenr mismatch, want=46451963543552, have=75208089814272 Couldn't read tree root Could not open root, trying backup super warning, device 14 is missing warning, device 13 is missing warning, device 12 is missing warning, device 11 is missing warning, device 10 is missing warning, device 9 is missing warning, device 8 is missing warning, device 7 is missing warning, device 6 is missing warning, device 5 is missing warning, device 4 is missing warning, device 3 is missing warning, device 2 is missing checksum verify failed on 22085632 found 5630EA32 wanted 1AA6FFF0 checksum verify failed on 22085632 found 5630EA32 wanted 1AA6FFF0 bad tree block 22085632, bytenr mismatch, want=22085632, have=1147797504 ERROR: cannot read chunk root Could not open root, trying backup super warning, device 14 is missing warning, device 13 is missing warning, device 12 is missing warning, device 11 is missing warning, device 10 is missing warning, device 9 is missing warning, device 8 is missing warning, device 7 is missing warning, device 6 is missing warning, device 5 is missing warning, device 4 is missing warning, device 3 is missing warning, device 2 is missing checksum verify failed on 22085632 found 5630EA32 wanted 1AA6FFF0 checksum verify failed on 22085632 found 5630EA32 wanted 1AA6FFF0 bad tree block 22085632, bytenr mismatch, want=22085632, have=1147797504 ERROR: cannot read chunk root Could not open root, trying backup super [root@cornelis ~]# uname -r 4.18.16-arch1-1-ARCH [root@cornelis ~]# btrfs --version btrfs-progs v4.19 -- Cheers, Patrick
