btrfs-send man page

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.

It is allowed to omit the -p <parent> option when -c <clone-src> options are given, in which case btrfs send will determine a suitable parent among the clone sources itself.

You must not specify clone sources unless you guarantee that these snapshots are exactly in the same state on both sides, the sender and the receiver.

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 useful to show the differences in metadata.

-v|--verbose

enable verbose output, print generated commands in a readable form, (each occurrence of this option increases the verbosity level)

-q|--quiet

suppress all messages except errors

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)

Referenced By

btrbk.conf(5), btrfs(8), btrfs-receive(8).

10/16/2017 Btrfs v4.13.3 Btrfs Manual