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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COLOPHON |
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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.
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⟩.
This page was obtained from the project's upstream Git repository
⟨git://git.kernel.org/pub/scm/linux/kernel/git/kdave/btrfs-progs.git⟩
on 2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-05-02.) If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to [email protected]
Btrfs v5.16.1 02/06/2022 BTRFS-SELECT-SUPER(8)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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