NAME

       btrfs-send - generate a stream of changes between two subvolume snapshots

SYNOPSIS

       btrfs send [-ve] [-p <parent>] [-c <clone-src>] [-f <outfile>] <subvol> [<subvol>...]

DESCRIPTION

       This  command  will  generate  a  stream of instructions that describe changes between two
       subvolume snapshots. The stream can be consumed by the btrfs receive command to  replicate
       the  sent snapshot on a different filesystem.  The command operates in two modes: full and
       incremental.

       All snapshots involved in one send command must be read-only, and this  status  cannot  be
       changed as long as there's a running send operation that uses the snapshot.

       In the full mode, the entire snapshot data and metadata will end up in the stream.

       In  the incremental mode (options -p and -c), previously sent snapshots that are available
       on both the sending and receiving side can be used to reduce  the  amount  of  information
       that has to be sent to reconstruct the sent snapshot on a different filesystem.

       The -p <parent> option can be omitted when -c <clone-src> options are given, in which case
       btrfs send will determine a suitable parent from among the clone sources.

       You must not specify clone sources unless you guarantee that these snapshots  are  exactly
       in the same state on both sides--both for the sender and the receiver. For implications of
       changed read-write status of a received snapshot please see  section  SUBVOLUME  FLAGS  in
       btrfs-subvolume(8).

       Options

       -e     if  sending  multiple subvolumes at once, use the new format and omit the 'end cmd'
              marker in the stream separating the subvolumes

       -p <parent>
              send an incremental stream from parent to subvol

       -c <clone-src>
              use this snapshot as a clone source for an incremental send (multiple allowed)

       -f <outfile>
              output is normally written to standard output so it can be, for example,  piped  to
              btrfs receive. Use this option to write it to a file instead.

       --no-data::
              send in NO_FILE_DATA mode

              The  output  stream  does  not  contain  any  file  data and thus cannot be used to
              transfer changes. This mode is faster and is useful  to  show  the  differences  in
              metadata.

       --proto <N>
              use send protocol version N

              The  default  is 1, which was the original protocol version. Version 2 encodes file
              data slightly more efficiently; it is also required  for  sending  compressed  data
              directly  (see  --compressed-data). Version 2 requires at least btrfs-progs 5.18 on
              both the sender and receiver and at least Linux 5.18 on the sender. Passing 0 means
              to use the highest version supported by the running kernel.

       --compressed-data
              send data that is compressed on the filesystem directly without decompressing it

              If  the  receiver supports the BTRFS_IOC_ENCODED_WRITE ioctl (added in Linux 5.18),
              it can also write it directly without decompressing it.   Otherwise,  the  receiver
              will fall back to decompressing it and writing it normally.

              This  requires  protocol  version  2  or  higher.  If  --proto  was  not used, then
              --compressed-data implies --proto 2.

       -q|--quiet
              (deprecated) alias for global -q option

       -v|--verbose
              (deprecated) alias for global -v option

       Global options

       -q|--quiet
              suppress all messages except errors

       -v|--verbose
              increase output verbosity, print generated commands in a readable form

EXIT STATUS

       btrfs send 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-receive(8), btrfs-subvolume(8)

COPYRIGHT

       2022