btrfs

Tuto ⇒ http://debian-facile.org/doc:systeme:btrfs

Hugo Mills on the btrfs mailing list wrote:Let's assume that you don't have a physical device failure (whichis a different set of tools -- mount -odegraded, btrfs dev delmissing). First thing to do is to take a btrfs-image -c9 -t4 of thefilesystem, and keep a copy of the output to show josef. smile Then start with -orecovery and -oro,recovery for pretty muchanything. If those fail, then look in dmesg for errors relating to the logtree -- if that's corrupt and can't be read (or causes a crash), usebtrfs-zero-log. If there's problems with the chunk tree -- the only one I've seenrecently was reporting something like "can't map address" -- thenchunk-recover may be of use.

After that, btrfsck is probably the next thing to try. If options -

s1, -s2, -s3 have any success, then btrfs-select-super will help byreplacing the superblock with one that works. If that's not going tobe useful, fall back to btrfsck --repair. Finally, btrfsck --repair --init-extent-tree may be necessary ifthere's a damaged extent tree. Finally, if you've got corruption inthe checksums, there's --init-csum-tree. Hugo.