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NAME | SYNOPSIS | DESCRIPTION | SUBCOMMAND | EXAMPLES | EXIT STATUS | AVAILABILITY | SEE ALSO | COLOPHON |
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BTRFS-REPLACE(8) Btrfs Manual BTRFS-REPLACE(8)
btrfs-replace - replace devices managed by btrfs with other
device.
btrfs replace <subcommand> <args>
btrfs replace is used to replace btrfs managed devices with other
device.
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 assumed 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
exists. (enable this if your drive has lots of read
errors, 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,
otherwise continue
-K|--nodiscard
Do not perform whole device TRIM operation on devices that
are capable of that. This does not affect discard/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
replace operation.
Options
-1
print once instead of print continuously until the replace
operation finishes (or is cancelled)
Example 1. 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/
btrfs replace returns a zero exit status if it succeeds. Non zero
is returned in case of failure.
btrfs is part of btrfs-progs. Please refer to the btrfs wiki
http://btrfs.wiki.kernel.org for further details.
mkfs.btrfs(8), btrfs-device(8), btrfs-filesystem(8),
This page is part of the btrfs-progs (btrfs filesystem tools)
project. Information about the project can be found at
⟨https://btrfs.wiki.kernel.org/index.php/Btrfs_source_repositories⟩.
If you have a bug report for this manual page, see
⟨https://btrfs.wiki.kernel.org/index.php/Problem_FAQ#How_do_I_report_bugs_and_issues.3F⟩.
This page was obtained from the project's upstream Git repository
⟨git://git.kernel.org/pub/scm/linux/kernel/git/kdave/btrfs-progs.git⟩
on 2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-06-23.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to [email protected]
Btrfs v5.16.1 02/06/2022 BTRFS-REPLACE(8)
Pages that refer to this page: btrfs(8), btrfs-device(8)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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