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 device.

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 [-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>.

               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 <targetdev>.

               no background replace.

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


               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 2020-11-01.  (At that time, the date of the most recent commit
       that was found in the repository was 2020-10-23.)  If you discover
       any rendering problems in this HTML version of the page, or you be‐
       lieve 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

Btrfs v4.6.1                     05/16/2020                 BTRFS-REPLACE(8)

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