1
0
mirror of https://github.com/Zygo/bees.git synced 2025-08-01 13:23:28 +02:00
Zygo Blaxell 27b5b4e113 roots: filter out NODATASUM files before attempting to scan them
Add a cheap check for `FS_NOCOW_FL` when we first encounter
each extent.  In the raw btrfs inode flags, the offending flag is
`BTRFS_INODE_NODATASUM`, because the restriction that prevents reflink
between datacow and "nodatacow" files is that a single inode is allowed
to have csums or not have csums, but must apply that choice to _all_
of its extents.

This extra check is cheaper than opening a file for each individual
reference to the extent, and then discovering that the file is
`FS_NOCOW_FL`, and then closing the file, over and over again.  It will
also avoid emitting a lot of noisy log messages.

Fixes: https://github.com/Zygo/bees/issues/313
Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2025-07-21 21:21:54 -04:00
2025-07-21 21:21:54 -04:00
2025-06-18 21:17:48 -04:00
2016-11-17 12:12:15 -05:00
2025-01-11 23:39:55 -05:00

BEES

Best-Effort Extent-Same, a btrfs deduplication agent.

About bees

bees is a block-oriented userspace deduplication agent designed to scale up to large btrfs filesystems. It is an offline dedupe combined with an incremental data scan capability to minimize time data spends on disk from write to dedupe.

Strengths

  • Space-efficient hash table - can use as little as 1 GB hash table per 10 TB unique data (0.1GB/TB)
  • Daemon mode - incrementally dedupes new data as it appears
  • Largest extents first - recover more free space during fixed maintenance windows
  • Works with btrfs compression - dedupe any combination of compressed and uncompressed files
  • Whole-filesystem dedupe - scans data only once, even with snapshots and reflinks
  • Persistent hash table for rapid restart after shutdown
  • Constant hash table size - no increased RAM usage if data set becomes larger
  • Works on live data - no scheduled downtime required
  • Automatic self-throttling - reduces system load
  • btrfs support - recovers more free space from btrfs than naive dedupers

Weaknesses

Installation and Usage

More Information

Bug Reports and Contributions

Email bug reports and patches to Zygo Blaxell bees@furryterror.org.

You can also use Github:

    https://github.com/Zygo/bees

Copyright 2015-2025 Zygo Blaxell bees@furryterror.org.

GPL (version 3 or later).

Description
Best-Effort Extent-Same, a btrfs dedupe agent
Readme 2.2 MiB
Languages
C++ 96.9%
C 1.7%
Makefile 0.8%
Shell 0.6%