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 [-Bfr] <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.

       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 filesystem:

           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 by:

           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.

SEE ALSO

       mkfs.btrfs(8), btrfs-device(8), btrfs-filesystem(8),