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