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btrfs-replace(8)
================
SYNOPSIS
--------
**btrfs replace** <subcommand> <args>
DESCRIPTION
-----------
:command:`btrfs replace` is used to replace btrfs managed devices with other device.
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 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 :doc:`btrfs-man5`.
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)
EXAMPLES
--------
Replacing an online drive with a bigger one
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Given the following filesystem mounted at :file:`/mnt/my-vault`
.. code-block:: none
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 :file:`/dev/sda` (*devid 1*) with a bigger drive located at
:file:`/dev/sdc` you would run the following:
.. code-block:: bash
btrfs replace start 1 /dev/sdc /mnt/my-vault/
You can monitor progress via:
.. code-block:: bash
btrfs replace status /mnt/my-vault/
After the replacement is complete, as per the docs at :doc:`btrfs-filesystem` in
order to use the entire storage space of the new drive you need to run:
.. code-block:: bash
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 <https://btrfs.readthedocs.io>`_.
SEE ALSO
--------
:doc:`btrfs-device`,
:doc:`btrfs-filesystem`,
:doc:`mkfs.btrfs`
|
