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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COLOPHON |
BTRFS-SELECT-SUPER(8) Btrfs Manual BTRFS-SELECT-SUPER(8)
btrfs-select-super - overwrite primary superblock with a backup copy
btrfs-select-super -s number <device>
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).
-s|--super <superblock>
use 'superblock’th superblock copy, valid values are 0 1 or 2 if
the respective superblock offset is within the device size
btrfs-inspect-internal(8), btrfsck check(8)
This page is part of the btrfs-progs (btrfs filesystem tools)
project. Information about the project can be found at
⟨https://btrfs.wiki.kernel.org/index.php/Btrfs_source_repositories⟩.
If you have a bug report for this manual page, see
⟨https://btrfs.wiki.kernel.org/index.php/Problem_FAQ#How_do_I_report_bugs_and_issues.3F⟩.
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on 2017-07-05. If you discover any rendering problems in this HTML
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Btrfs v4.6.1 07/16/2016 BTRFS-SELECT-SUPER(8)