1
0
mirror of https://github.com/Zygo/bees.git synced 2025-05-17 13:25:45 +02:00
Zygo Blaxell bf2a014607 roots: improve "RO root 6094" message
This sequence of log messages isn't clear:

	crawl_master: WORKAROUND: Avoiding RO subvol 6094
	crawl_master: WORKAROUND: RO root 6094

The first is from a cache miss, and appears wherever a root is opened
(dedupe or crawl).  The second is skipping an entire subvol scan, and
only happens in crawl_master.

Elaborate on the second message a little.

Also use the term "root" consistently when referring to subvol tree IDs.
btrfs refers to these objects by (at least) three distinct names:  tree,
subvol, and root.  Using three different words for the same thing is worse
than using a single wrong word consistently to refer to the same concept.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>
2018-11-22 21:10:15 -05:00
2018-11-22 21:10:15 -05:00
2016-11-17 12:12:15 -05:00

BEES

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

About bees

bees is a block-oriented userspace deduplication agent designed for 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 and matching algorithms - can use as little as 1 GB hash table per 10 TB unique data (0.1GB/TB)
  • Incremental realtime dedupe of new data using btrfs tree search
  • Works with btrfs compression - dedupe any combination of compressed and uncompressed files
  • Works around btrfs filesystem structure to free more disk space
  • Persistent hash table for rapid restart after shutdown
  • Whole-filesystem dedupe - including snapshots
  • Constant hash table size - no increased RAM usage if data set becomes larger
  • Works on live data - no scheduled downtime required
  • Automatic self-throttling based on system load

Weaknesses

  • Whole-filesystem dedupe - has no include/exclude filters, does not accept file lists
  • Runs continuously as a daemon - no quick start/stop
  • Requires root privilege (or CAP_SYS_ADMIN)
  • First run may require temporary disk space for extent reorganization
  • First run may increase metadata space usage if many snapshots exist
  • Constant hash table size - no decreased RAM usage if data set becomes smaller
  • btrfs only

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 2015-2018 Zygo Blaxell bees@furryterror.org.

GPL (version 3 or later).

Description
Best-Effort Extent-Same, a btrfs dedupe agent
Readme 1.7 MiB
Languages
C++ 97%
C 1.6%
Makefile 0.8%
Shell 0.6%