BTRFS-REPLACE(8) BTRFS BTRFS-REPLACE(8)
NAME
btrfs-replace - replace devices managed by btrfs with other device
SYNOPSIS
btrfs replace <subcommand> <args>
DESCRIPTION
btrfs replace is used to replace btrfs managed devices with other de-
vice.
SUBCOMMAND
cancel <mount_point>
Cancel a running device replace operation.
start [options] <srcdev>|<devid> <targetdev> <path>
Replace device of a btrfs filesystem.
On a live filesystem, duplicate the data to the target device
which is currently stored on the source device. If the source
device is not available anymore, or if the -r option is set, the
data is built only using the RAID redundancy mechanisms. After
completion of the operation, the source device is removed from
the filesystem. If the srcdev is a numerical value, it is as-
sumed to be the device id of the filesystem which is mounted at
path, otherwise it is the path to the source device. If the
source device is disconnected, from the system, you have to use
the devid parameter format. The targetdev needs to be same size
or larger than the srcdev.
NOTE:
The filesystem has to be resized to fully take advantage of a
larger target device; this can be achieved with btrfs
filesystem resize <devid>:max /path
Options
-r only read from srcdev if no other zero-defect mirror ex-
ists. (enable this if your drive has lots of read er-
rors, the access would be very slow)
-f force using and overwriting targetdev even if it looks
like it contains a valid btrfs filesystem.
A valid filesystem is assumed if a btrfs superblock is
found which contains a correct checksum. Devices that are
currently mounted are never allowed to be used as the
targetdev.
-B no background replace.
--enqueue
wait if there's another exclusive operation running, oth-
erwise continue
-K|--nodiscard
Do not perform whole device TRIM operation on devices
that are capable of that. This does not affect dis-
card/trim operation when the filesystem is mounted.
Please see the mount option discard for that in btrfs(5).
status [-1] <mount_point>
Print status and progress information of a running device re-
place operation.
Options
-1 print once instead of print continuously until the re-
place operation finishes (or is cancelled)
EXAMPLES
Replacing an online drive with a bigger one
Given the following filesystem mounted at /mnt/my-vault
Label: 'MyVault' uuid: ae20903e-b72d-49ba-b944-901fc6d888a1
Total devices 2 FS bytes used 1TiB
devid 1 size 1TiB used 500.00GiB path /dev/sda
devid 2 size 1TiB used 500.00GiB path /dev/sdb
In order to replace /dev/sda (devid 1) with a bigger drive located at
/dev/sdc you would run the following:
btrfs replace start 1 /dev/sdc /mnt/my-vault/
You can monitor progress via:
btrfs replace status /mnt/my-vault/
After the replacement is complete, as per the docs at
btrfs-filesystem(8) in order to use the entire storage space of the new
drive you need to run:
btrfs filesystem resize 1:max /mnt/my-vault/
EXIT STATUS
btrfs replace returns a zero exit status if it succeeds. Non zero is
returned in case of failure.
AVAILABILITY
btrfs is part of btrfs-progs. Please refer to the documentation at
https://btrfs.readthedocs.io.
SEE ALSO
btrfs-device(8), btrfs-filesystem(8), mkfs.btrfs(8)
6.6.3 Mar 31, 2024 BTRFS-REPLACE(8)
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