btrfs-replace(8) — Linux manual page


BTRFS-REPLACE(8)              Btrfs Manual              BTRFS-REPLACE(8)

NAME         top

       btrfs-replace - replace devices managed by btrfs with other

SYNOPSIS         top

       btrfs replace <subcommand> <args>

DESCRIPTION         top

       btrfs replace is used to replace btrfs managed devices with other

SUBCOMMAND         top

       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

               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

               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)

               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

               no background replace.

               wait if there’s another exclusive operation running,
               otherwise continue

       status [-1] <mount_point>
           Print status and progress information of a running device
           replace operation.


               print once instead of print continuously until the
               replace operation finishes (or is cancelled)

EXAMPLES         top

       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/

EXIT STATUS         top

       btrfs replace returns a zero exit status if it succeeds. Non zero
       is returned in case of failure.

AVAILABILITY         top

       btrfs is part of btrfs-progs. Please refer to the btrfs wiki for further details.

SEE ALSO         top

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

COLOPHON         top

       This page is part of the btrfs-progs (btrfs filesystem tools)
       project.  Information about the project can be found at 
       If you have a bug report for this manual page, see
       This page was obtained from the project's upstream Git repository
       on 2021-08-27.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-07-30.)  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

Btrfs v4.6.1                   03/13/2021               BTRFS-REPLACE(8)

Pages that refer to this page: btrfs(8)btrfs-device(8)