The main thing you haven't tried here is mount -o degraded, which is the thing to do if you have a missing device in your array.
Also, that kernel's not really all that good for a parity RAID array -- it's the very first one that had the scrub and replace implementation, so it's rather less stable with parity RAID than the later 4.x kernels. That's probably not the issue here, though. Hugo. On Fri, Mar 18, 2016 at 06:41:32PM +0100, Marcin Solecki wrote: > Hello all, > I give up for this problem at restore my data > > > # uname -a > Linux jarvis.home 4.5.0-1.el7.elrepo.x86_64 > > # btrfs --version > btrfs-progs v3.19.1 > > # btrfs fi show > warning, device 4 is missing > bytenr mismatch, want=21020672, have=21217280 > Couldn't read chunk root > Label: none uuid: 27ef2638-b50a-4243-80ed-40c3733ec11d > Total devices 4 FS bytes used 2.50TiB > devid 1 size 931.51GiB used 899.71GiB path /dev/sdd > devid 2 size 931.51GiB used 899.69GiB path /dev/sdb > devid 3 size 931.51GiB used 899.69GiB path /dev/sdc > *** Some devices missing > > # mount -o recovery /dev/sda /srv/ > mount: wrong fs type, bad option, bad superblock on /dev/sda, > missing codepage or helper program, or other error > > In some cases useful info is found in syslog - try > dmesg | tail or so. > > dmesg after : > [ 4886.521315] BTRFS info (device sdc): enabling auto recovery > [ 4886.521320] BTRFS info (device sdc): disk space caching is enabled > [ 4886.522853] BTRFS: failed to read chunk tree on sdc > [ 4886.528789] BTRFS: open_ctree failed > > #btrfs check --repair /dev/sda > enabling repair mode > warning, device 4 is missing > bytenr mismatch, want=21020672, have=21217280 > Couldn't read chunk root > Couldn't open file system > > # btrfs rescue chunk-recover -v /dev/sda > All Devices: > Device: id = 3, name = /dev/sdc > Device: id = 2, name = /dev/sdb > Device: id = 1, name = /dev/sda > > [ 5164.468272] btrfs[3653]: segfault at 7f454014172e ip > 0000000000423479 sp 00007f4482cec880 error 4 in btrfs[400000+83000] > [ 5168.928317] btrfs[3657]: segfault at 7fd18c14172e ip > 0000000000423479 sp 00007fd0d5858880 error 4 in btrfs[400000+83000] > [ 5173.812457] btrfs[3662]: segfault at 7fd76c14172e ip > 0000000000423479 sp 00007fd6b0e59880 error 4 in btrfs[400000+83000] > > # btrfs rescue super-recover -v /dev/sda > All Devices: > Device: id = 3, name = /dev/sdc > Device: id = 2, name = /dev/sdb > Device: id = 1, name = /dev/sda > > Before Recovering: > [All good supers]: > device name = /dev/sdc > superblock bytenr = 65536 > > device name = /dev/sdc > superblock bytenr = 67108864 > > device name = /dev/sdc > superblock bytenr = 274877906944 > > device name = /dev/sdb > superblock bytenr = 65536 > > device name = /dev/sdb > superblock bytenr = 67108864 > > device name = /dev/sdb > superblock bytenr = 274877906944 > > device name = /dev/sda > superblock bytenr = 65536 > > device name = /dev/sda > superblock bytenr = 67108864 > > device name = /dev/sda > superblock bytenr = 274877906944 > > [All bad supers]: > > All supers are valid, no need to recover > > # btrfs-show-super /dev/sda > superblock: bytenr=65536, device=/dev/sda > --------------------------------------------------------- > csum 0x61b509bb [match] > bytenr 65536 > flags 0x1 > magic _BHRfS_M [match] > fsid 27ef2638-b50a-4243-80ed-40c3733ec11d > label > generation 69462 > root 1648640000 > sys_array_size 290 > chunk_root_generation 48545 > root_level 1 > chunk_root 21020672 > chunk_root_level 1 > log_root 0 > log_root_transid 0 > log_root_level 0 > total_bytes 4000819544064 > bytes_used 2743528714240 > sectorsize 4096 > nodesize 16384 > leafsize 16384 > stripesize 4096 > root_dir 6 > num_devices 4 > compat_flags 0x0 > compat_ro_flags 0x0 > incompat_flags 0xe1 > ( MIXED_BACKREF | > BIG_METADATA | > EXTENDED_IREF | > RAID56 ) > csum_type 0 > csum_size 4 > cache_generation 69462 > uuid_tree_generation 69462 > dev_item.uuid 70f4650c-e01d-4613-bd7a-a6834c1c44bb > dev_item.fsid 27ef2638-b50a-4243-80ed-40c3733ec11d [match] > dev_item.type 0 > dev_item.total_bytes 1000204886016 > dev_item.bytes_used 966057263104 > dev_item.io_align 4096 > dev_item.io_width 4096 > dev_item.sector_size 4096 > dev_item.devid 1 > dev_item.dev_group 0 > dev_item.seek_speed 0 > dev_item.bandwidth 0 > dev_item.generation 0 > > thx for helps > -- Hugo Mills | You can't expect a boy to be vicious until he's gone hugo@... carfax.org.uk | to a good school. http://carfax.org.uk/ | PGP: E2AB1DE4 | Saki
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