btrfs-send-stream · shipping · also Btrfs send/receive stream

Btrfs send stream

A Btrfs send stream is a versioned sequence of commands describing a subvolume or changes needed to reconstruct it from existing state.

Full and incremental transfers use the same command format. An incremental transfer can reference a parent and other clone sources, whose corresponding state must remain available and unchanged. The no-data mode omits file payload and is not a data-recovery copy. [1]

The format carries per-command CRC32C and subvolume references; it is not a sector image. A successful receive --dump decodes the stream without applying it to a destination, so it cannot establish target dependency availability or successful restoration. [2] [3]

Six synthetic protocol-v1 dump controls on btrfs-progs v6.6.3 accepted a stream with its whole WRITE command removed and a snapshot reference without any destination parent lookup. A flipped payload bit, absent END and truncated command were rejected. These are parser observations, not actual receives or measured backup failures. [5]

Relations

related

btrfs, btrfs-received-uuid, btrfs-read-only-subvolume, incremental-backup, reflink

Limitations

• Command checksums do not authenticate the sender; the receive manual warns against untrusted streams. [1, 2, 3]

Citations

1. btrfs-progs v6.17: send modes and clone-source preconditions (accessed 2026-10-18)
2. btrfs-progs v6.17: send stream format and reference fields (accessed 2026-10-18)
3. btrfs-progs v6.17: receive validation, write window and trust warning (accessed 2026-10-18)
5. Hesela: six Btrfs dump parser controls, fixture hashes and recorded environment (accessed 2026-10-18)

Further reading

4. Keeping Btrfs incremental backups recoverable (accessed 2026-10-18)

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