borg

This is borg2!
--------------

Please note that this is the README for (unstable) Borg2 / master branch.

For general project infos, versioned docs, screen casts, please see there:

https://www.borgbackup.org/

Borg2 is currently in beta testing and might get major and/or
breaking changes between beta releases (and there is no beta to
next-beta upgrade code, so you will have to delete and re-create repos).

Thus, **DO NOT USE BORG2 FOR YOUR PRODUCTION BACKUPS!** Please help with
testing it, but set it up *additionally* to your production backups.


What is BorgBackup?
-------------------

BorgBackup (short: Borg) is a deduplicating backup program.
Optionally, it supports compression and authenticated encryption.

The main goal of Borg is to provide an efficient and secure way to back up data.
The data deduplication technique used makes Borg suitable for daily backups
since only changes are stored.
The authenticated encryption technique makes it suitable for backups to targets not
fully trusted.

See the `installation manual`_ or, if you have already
downloaded Borg, ``docs/installation.rst`` to get started with Borg.

.. _installation manual: https://borgbackup.readthedocs.io/en/master/installation.html

Main features
~~~~~~~~~~~~~

**Space efficient storage**
  Deduplication based on content-defined chunking is used to reduce the number
  of bytes stored: each file is split into a number of variable length chunks
  and only chunks that have never been seen before are added to the repository.

  A chunk is considered duplicate if its id_hash value is identical.
  A cryptographically strong hash or MAC function is used as id_hash,
  e.g. (hmac-)sha256 or (keyed) blake3.

  To deduplicate, all the chunks in the same repository are considered, no
  matter whether they come from different machines, from previous backups,
  from the same backup or even from the same single file.

  Compared to other deduplication approaches, this method does NOT depend on:

  * file/directory names staying the same: So you can move your stuff around
    without killing the deduplication, even between machines sharing a repo.

  * complete files or time stamps staying the same: If a big file changes a
    little, only a few new chunks need to be stored - this is great for VMs or
    raw disks.

  * The absolute position of a data chunk inside a file: Stuff may get shifted
    and will still be found by the deduplication algorithm.

  Supported chunkers:

  * fastcdc (the default)
  * buzhash64 (improved), buzhash (as in borg 1.x)
  * toeplitz-aes / rabin-aes / goldilocks-aes (keyed, AES-based; they make
    chunk-boundary fingerprinting attacks much harder)
  * fixed (fixed blocksize, optionally with a differently sized header)

**Speed**
  * performance-critical code (chunking, compression, encryption) is
    implemented in C/Cython, using SIMD (NEON / AVX2 / AVX-512) where that
    is a win - the scan kernel is picked per platform
  * local caching
  * quick detectio