blob: 6e94a034f482ad42830181b21939b3ecfa320bb1 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
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, 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 <superblock>::
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)
|
