---
name: "btrfs-select-super"
section: "8"
platform: "linux"
package: "btrfs-progs"
version: "7.3-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/btrfs-select-super"
---

# btrfs-select-super(8)

overwrite primary superblock with a backup copy

## 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)](/btrfs/8.md) \<\>