Borg Backup

"The holy grail of backup software"

Thomas Waldmann @ GPN16

Borg - a fork of Attic

• Attic: about 5y old, good design, proven code

• but:

  • going slowly

  • some bugs and annoyances

  • not very open to new developers
     

• Borg Backup: fork of Attic, now ~1y old

• and:

  • a community project, bus_factor++

  • has a lot of fixes and good PRs merged

  • open and inviting to new contributors

  • faster paced

Feature Set (1)

• easy and fast
• content-defined chunking (*)
• chunk deduplication (*)
• lz4, zlib, lzma compression

• encryption with AES256

• authentication with HMAC-SHA2

• simple backend (k/v, fs, via ssh)

Feature Set (2)

• FOSS (BSD license)

• good docs

• good platform / arch support

• xattr / acl support

• mount a backup via FUSE

• Python 3.4+, a little Cython & C

• good test coverage, CI

Deduplication (1)

• No problem with:
  • VM images (sparse file support)
  • (physical) disk images
  • renamed huge directories
  • inner deduplication of data set
  • historical deduplication
  • dedups different machines

Deduplication (2)

• Content defined chunking:
  • "buzhash" rolling hash
  • cut data when hash has specific bit pattern,
    yields chunks with ~ 2^n bytes target size
  • n + other chunker params configurable now
  • seeded, to avoid fingerprinting chunk lengths
     
• Store chunks under id into store:
  • id = HASH(chunk), or
  • id = HMAC(id_key, chunk)

Borg Backup - Links

github.com/borgbackup
 

#borgbackup on chat.freenode.net

Questions / Feedback?

14:30 kleiner Workshopraum: Code / Project Tour

20:00 ZKM-Vortragssaal: Talk