---
title: btrfs failed device
toc: true
---

Scan for btrfs devices
----------------------

`btrfs device scan`

Show btrfs devices
------------------

`btrfs filesystem show`

```
# btrfs fi sh
Label: 'btrfs-pool'  uuid: 12345678-1234-1234-1234-123456789012
    Total devices 4 FS bytes used 8.01TiB
    devid    1 size 5.46TiB used 5.46TiB path /dev/mapper/luks1
    devid    2 size 2.73TiB used 2.73TiB path /dev/mapper/luks2
    devid    3 size 2.73TiB used 2.73TiB path /dev/mapper/luks3
    devid    5 size 5.46TiB used 5.46TiB path /dev/sdd
```

Mount btrfs volume in degraded state
------------------------------------

`mount -o degraded /dev/sdx /mnt/btrfs-pool`

or if you're using luks:

`mount -o degraded /dev/mapper/luksx /mnt/btrfs-pool`

Replace failed device
---------------------

See [luks and btrfs](howto_luks_and_btrfs.html) for creating new luks
encrypted devices.

*Change _x_ to match the device, and _y_ to match the device ID.*

`btrfs replace start y /dev/mapper/luksx /mnt/btrfs-pool`

```
# btrfs filesystem show
Label: 'btrfs-pool'  uuid: 12345678-1234-1234-1234-123456789abc
	Total devices 5 FS bytes used 8.01TiB
	devid    0 size 2.73TiB used 2.73TiB path /dev/mapper/luks2
	devid    1 size 5.46TiB used 5.46TiB path /dev/mapper/luks1
	devid    3 size 2.73TiB used 2.73TiB path /dev/mapper/luks3
	devid    5 size 5.46TiB used 5.46TiB path /dev/sdd
	*** Some devices missing
```

Check status of replace
-----------------------

`btrfs replace status -1 /mnt/btrfs-pool`

```
# btrfs replace status -1 /mnt/btrfs-pool
0.5% done, 0 write errs, 0 uncorr. read errs
```

Larger disk
-----------

Don't forget to resize if you are replacing with a larger disk, where
_x_ is the devid:

```
btrfs filesystem resize x:max /mnt/btrfs-pool
```