btrfs-select-super(8) ===================== NAME ---- btrfs-select-super - overwrite primary superblock with a backup copy SYNOPSIS -------- *btrfs-select-super* -s number DESCRIPTION ----------- Destructively overwrite all copies of the superblock with a specified copy. This helps in certain cases, for example when write barriers were disabled during a power failure and not all superblocks were written, or if the primary superblock is damaged, eg. accidentally overwritten. The filesystem specified by 'device' must not be mounted. NOTE: *Prior to overwriting the primary superblock, please make sure that the backup copies are valid!* To dump a superblock use the *btrfs inspect-internal dump-super* command, or the obsolete command *btrfs-show-super*. Then run the check (in the non-repair mode) using the command *btrfs check -s* where '-s' specifies the superblock copy to use. Superblock copies exist in the following offsets on the device: - primary: '64KiB' (65536) - 1st copy: '64MiB' (67108864) - 2nd copy: '256GiB' (274877906944) A superblock size is '4KiB' (4096). OPTIONS ------- -s|--super :: use 'superblock'th superblock copy, valid values are 0 1 or 2 if the respective superblock offset is within the device size SEE ALSO -------- `btrfs-inspect-internal`(8), `btrfsck check`(8)