BTRFS-SELECT-SUPER(8)		     BTRFS		 BTRFS-SELECT-SUPER(8)

NAME
       btrfs-select-super - overwrite primary superblock with a backup copy

SYNOPSIS
       btrfs-select-super -s number <device>

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, e.g. 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.

       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 <N>
	      use Nth superblock copy, valid values are 0 1 or 2 if the
	      respective superblock offset is within the device size

SEE ALSO
       btrfs(8)

6.16.1			      September 10, 2025	 BTRFS-SELECT-SUPER(8)