BTRFS-SEND(8) BTRFS BTRFS-SEND(8)
NAME
btrfs-send - generate a stream of changes between two subvolume snap-
shots
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. Read-only mount of the subvolume is not suffi-
cient, there's no way to guarantee that there won't be any other
writable mount of the same subvolume that would potentially write while
send would be running.
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. Ver-
sion 2 encodes file data slightly more efficiently; it is also
required for sending compressed data directly (see --com-
pressed-data). Version 2 requires at least btrfs-progs 6.0 on
both the sender and receiver and at least Linux 6.0 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 6.0), it can also write it directly without de-
compressing it. Otherwise, the receiver will fall back to de-
compressing 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 read-
able form
EXIT STATUS
btrfs send returns a zero exit status if it succeeds. Non zero is re-
turned in case of failure.
AVAILABILITY
btrfs is part of btrfs-progs. Please refer to the documentation at
https://btrfs.readthedocs.io.
SEE ALSO
btrfs-receive(8), btrfs-subvolume(8), mkfs.btrfs(8)
6.6.3 Mar 31, 2024 BTRFS-SEND(8)
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