On Wed, 06 May 2015 11:55:51 +0000, Duncan wrote: > Since then, I had to use it again myself, updating my year-old personal > experience. Among other things, btrfs-progs v4.0 has a new metadata > restore option, which should restore ownership/perms/dates as well as the > file data. There's a patch to restore symlinks too, but it apparently > didn't make it into 4.0, so you'll have to try the integration branch or > apply it manually after finding it on the list. The looping too many > times point apparently doesn't apply any more, at least on a full run, > tho it still cuts short if you use the dry-run option. Additionally, the > dry-run option gave me some metadata restoration errors that a full write- > files run didn't give me, so dry-run ends up being rather more > pessimistic about what can be restored than what it actually restores. > > If you're lucky, restore will "just work". If not, you can try feeding > it roots you found using btrfs-find-root, as detailed in the above post. > On my recent experience I was lucky and it worked without that, so I > didn't get to update my personal experience knowledge in that regard. Duncan, Many thanks for taking the time to look at my case, and to make the effort of writing such an elaborate response - much appreciated. I understand the direction I should be taking, and by just reading your response have learned quite a bit already. Unfortunately I got stranded right at the get-go, with the btrfs-show super command not working for me. Let me share a couple of outputs, and hopefully you or others can point me where to go from here. As a side-note, I did update to btrfs-progs 4.0 from 3.19.2 as suggested. $ btrfs --version btrfs-progs v4.0 $ sudo uname -a Linux thejay-srv03 4.0.0-040000-generic #201504121935 SMP Sun Apr 12 23:36:33 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux Just for clarity - this is a btrfsraid6 pool. $ sudo btrfs fi show /dev/sdy warning, device 2 is missing warning devid 2 not found already checksum verify failed on 21200896 found 44715E95 wanted A092E323 checksum verify failed on 21200896 found 91AC994F wanted 987F5E0F checksum verify failed on 21200896 found 44715E95 wanted A092E323 bytenr mismatch, want=21200896, have=65536 Couldn't read chunk tree Label: 'roms03' uuid: b0025417-4045-4c63-a432-0625b7cc41ea Total devices 4 FS bytes used 2.67TiB devid 1 size 1.36TiB used 1.36TiB path /dev/sdy devid 3 size 1.36TiB used 1.36TiB path /dev/sdz devid 4 size 1.36TiB used 1.36TiB path /dev/sdaa *** Some devices missing btrfs-progs v4.0 $ sudo btrfs-find-root /dev/sdy warning, device 2 is missing warning devid 2 not found already Couldn't read chunk tree Open ctree failed (above output is the same for the other 2 drives sdz and sdaa) $ sudo btrfs-show-super /dev/sdy superblock: bytenr=65536, device=/dev/sdy --------------------------------------------------------- csum 0x8c55bcfe [match] bytenr 65536 flags 0x1 magic _BHRfS_M [match] fsid b0025417-4045-4c63-a432-0625b7cc41ea label roms03 generation 17310 root 1622245376 sys_array_size 290 chunk_root_generation 16372 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 6001207640064 bytes_used 2937720725504 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 4 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x1e1 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF | RAID56 | SKINNY_METADATA ) csum_type 0 csum_size 4 cache_generation 17310 uuid_tree_generation 17310 dev_item.uuid f39d7af1-1eec-4f99-8353-4c70371e1942 dev_item.fsid b0025417-4045-4c63-a432-0625b7cc41ea [match] dev_item.type 0 dev_item.total_bytes 1500301910016 dev_item.bytes_used 1500301885440 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 ---- $ sudo btrfs-show-super /dev/sdz superblock: bytenr=65536, device=/dev/sdz --------------------------------------------------------- csum 0xb48f16eb [match] bytenr 65536 flags 0x1 magic _BHRfS_M [match] fsid b0025417-4045-4c63-a432-0625b7cc41ea label roms03 generation 17310 root 1622245376 sys_array_size 290 chunk_root_generation 16372 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 6001207640064 bytes_used 2937720725504 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 4 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x1e1 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF | RAID56 | SKINNY_METADATA ) csum_type 0 csum_size 4 cache_generation 17310 uuid_tree_generation 17310 dev_item.uuid 6560226f-a966-4699-8a9e-e7377d436cc6 dev_item.fsid b0025417-4045-4c63-a432-0625b7cc41ea [match] dev_item.type 0 dev_item.total_bytes 1500301910016 dev_item.bytes_used 1500300836864 dev_item.io_align 4096 dev_item.io_width 4096 dev_item.sector_size 4096 dev_item.devid 3 dev_item.dev_group 0 dev_item.seek_speed 0 dev_item.bandwidth 0 dev_item.generation 0 ---- $ sudo btrfs-show-super /dev/sdaa superblock: bytenr=65536, device=/dev/sdaa --------------------------------------------------------- csum 0xf3cbbf1f [match] bytenr 65536 flags 0x1 magic _BHRfS_M [match] fsid b0025417-4045-4c63-a432-0625b7cc41ea label roms03 generation 17310 root 1622245376 sys_array_size 290 chunk_root_generation 16372 root_level 1 chunk_root 20971520 chunk_root_level 1 log_root 0 log_root_transid 0 log_root_level 0 total_bytes 6001207640064 bytes_used 2937720725504 sectorsize 4096 nodesize 16384 leafsize 16384 stripesize 4096 root_dir 6 num_devices 4 compat_flags 0x0 compat_ro_flags 0x0 incompat_flags 0x1e1 ( MIXED_BACKREF | BIG_METADATA | EXTENDED_IREF | RAID56 | SKINNY_METADATA ) csum_type 0 csum_size 4 cache_generation 17310 uuid_tree_generation 17310 dev_item.uuid 3c026bb0-dcf0-45da-8c90-cb668323180d dev_item.fsid b0025417-4045-4c63-a432-0625b7cc41ea [match] dev_item.type 0 dev_item.total_bytes 1500301910016 dev_item.bytes_used 1500300836864 dev_item.io_align 4096 dev_item.io_width 4096 dev_item.sector_size 4096 dev_item.devid 4 dev_item.dev_group 0 dev_item.seek_speed 0 dev_item.bandwidth 0 dev_item.generation 0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
