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. 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 detection of unmodified files Data encryption All data can be protected client-side using 256-bit authenticated encryption (AES-OCB or chacha20-poly1305), ensuring data confidentiality, integrity and authenticity. If you do not need confidentiality, there are also modes that only authenticate (authenticated-sha256 / authenticated-blake3). Hashing You can choose between HMAC-SHA256 and Blake3. Obfuscation Optionally, Borg can actively obfuscate, e.g., the size of files/chunks to make fingerprinting attacks more difficult. Compression All data can be optionally compressed: lz4 (super fast, low compression) zstd (wide range from high speed and low compression to high compression and lower speed) zlib (medium speed and compression) lzma (low speed, high compression) Off-site backups Borg can store data on any remote host accessible via misc. protocols: ssh:// (REST-http-over-stdio-over-ssh) and http(s):// (REST-http-over-tcp). Significant performance gains can be achieved with these by having a remote agent (borg must be installed on the repo server). sftp:// s3:// / b2:// rclone: - lots of protocols / providers supported by rclone Backups mountable as file systems Backup archives are mountable as user-space file systems for easy interactive backup examination and restores (e.g., by using a regular file manager). Easy installation on multiple platforms We offer single-file binaries that do not require installing anything - you can just run them on these platforms: Linux (x86_64, arm64) macOS (arm64, x86_64) FreeBSD (x86_64) Windows (x86_64, MSYS2/MINGW borg.exe, experimental) Borg also runs on these platforms, but you need to install it from a package or from source: NetBSD (xattrs, but no ACLs) OpenBSD (no xattrs/ACLs support) illumos / Solaris (xattrs, but no ACLs) Cygwin (experimental) Windows Subsystem for Linux (WSL) on Windows 10/11 (experimental) Free and Open Source Software security and functionality can be audited independently licensed under the BSD (3-clause) license, see License for the complete license Easy to use For ease of use, set the BORG_REPO environment variable: $ export BORG_REPO=/path/to/repo Create a new backup repository (see borg repo-create --help for encryption options): $ borg repo-create --encryption=aes256-ocb --key-location=repokey Create a new backup archive: $ borg create docs ~/Documents Now do another backup, just to show off the great deduplication: $ borg create -v --stats docs ~/Documents Creating archive "docs" in repository /path/to/repo Repository: /path/to/repo Archive name: docs Archive fingerprint: 7714aef97c1a24539cc3dc73f79b060f14af04e2541da33d54c7ee8e81a00089 Time (nominal): Mon, 2026-08-03 19:57:35 +0200 Time (start): Mon, 2026-08-03 19:57:35 +0200 Time (end): Mon, 2026-08-03 19:57:35 +0200 Duration: 0.01 seconds Number of files: 24 Original size: 29.73 MB Deduplicated size: 520 B ... For demo videos, check out our homepage: https://www.borgbackup.org/#demo Helping, donations and bounties, becoming a Patron Your help is always welcome! Spread the word, give feedback, help with documentation, testing or development. You can also give monetary support to the project, see here for details: https://www.borgbackup.org/#fund Thanks to every