btrfs-send

Generate a stream of btrfs subvolume changes for backup and replication

TLDR

Send a snapshot to stdout

$ btrfs send [/path/to/snapshot]

Send to a file

$ btrfs send [/path/to/snapshot] -f [backup.send]

Send incremental (only differences from parent)

$ btrfs send -p [/path/to/parent] [/path/to/snapshot]

Send with multiple clone sources

$ btrfs send -c [/path/to/clone1] -c [/path/to/clone2] [/path/to/snapshot]

Send and receive in one pipeline

$ btrfs send [/path/to/snapshot] | btrfs receive [/path/to/destination]

Send incremental over SSH

$ btrfs send -p [/snapshots/old] [/snapshots/new] | ssh [user@host] btrfs receive [/backup]

Quiet mode (no progress)

$ btrfs send -q [/path/to/snapshot]

SYNOPSIS

btrfs send [-v] [-p parent] [-c clone-src] [-f outfile] subvolume

btrfs send generates a stream of instructions representing a btrfs subvolume or snapshot. This stream can be received by btrfs receive to recreate the subvolume on another filesystem, enabling backup and replication workflows.The send operation works on read-only snapshots and produces a binary stream containing file data, metadata, and structural information. When a parent snapshot is specified, only the differences (incremental send) are transmitted, dramatically reducing transfer size for regular backups.The stream format is forward-compatible and can be piped directly, saved to a file, or transferred over network connections like SSH.

PARAMETERS

-f file

Write stream to file instead of stdout.

-p parent

Parent subvolume for incremental send.

-c clone-src

Clone source (additional reference for deduplication).

-v

Verbose mode.

-q

Quiet mode (no progress).

--no-data

Send without file data (metadata only).

-e

End stream after subvolume data.

--proto N

Use send stream protocol version N.

INSTALL

sudo apt install btrfs-progs

sudo dnf install btrfs-progs

sudo pacman -S btrfs-progs

sudo apk add btrfs-progs

brew install btrfs-progs

nix profile install nixpkgs#btrfs-progs

CAVEATS

Source subvolume must be read-only. Parent snapshot must exist on receive side for incremental restores. Stream is not human-readable. Interrupting send/receive may leave incomplete subvolumes. File permissions and ownership require appropriate privileges to restore. Compressed send streams require protocol version 2+.

HISTORY

btrfs send/receive was introduced in Linux kernel 3.6 (released September 2012) as part of btrfs development. It was designed to enable efficient snapshot-based backup and replication, similar to ZFS send/receive. The feature has been enhanced over time with compressed transfers (protocol v2) and improved performance for large filesystems.