Ubuntu Manpage: btrfs-replace - replace devices managed by btrfs with other device

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 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 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)

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 btrfs wiki http://btrfs.wiki.kernel.org
       for further details.