Borg Documentation

BorgBackup Installation and Basic Usage

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 backup 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 not fully trusted targets.

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.

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 will 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.

Speed
  • performance critical code (chunking, compression, encryption) is implemented in C/Cython
  • local caching of files/chunks index data
  • quick detection of unmodified files
Data encryption
All data can be protected using 256-bit AES encryption, data integrity and authenticity is verified using HMAC-SHA256. Data is encrypted clientside.
Compression
All data can be compressed by lz4 (super fast, low compression), zlib (medium speed and compression) or lzma (low speed, high compression).
Off-site backups
Borg can store data on any remote host accessible over SSH. If Borg is installed on the remote host, big performance gains can be achieved compared to using a network filesystem (sshfs, nfs, ...).
Backups mountable as filesystems
Backup archives are mountable as userspace filesystems 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 does not require installing anything - you can just run it on the supported platforms:

  • Linux
  • Mac OS X
  • FreeBSD
  • OpenBSD and NetBSD (no xattrs/ACLs support or binaries yet)
  • Cygwin (not supported, no binaries yet)
Free and Open Source Software
  • security and functionality can be audited independently
  • licensed under the BSD (3-clause) license

Easy to use

Initialize a new backup repository and create a backup archive:

$ borg init /mnt/backup
$ borg create /mnt/backup::Monday ~/Documents

Now doing another backup, just to show off the great deduplication:

$ borg create --stats -C zlib,6 /mnt/backup::Tuesday ~/Documents

Archive name: Tuesday
Archive fingerprint: 387a5e3f9b0e792e91c...
Start time: Tue Mar 25 12:00:10 2014
End time:   Tue Mar 25 12:00:10 2014
Duration: 0.08 seconds
Number of files: 358
                  Original size    Compressed size    Deduplicated size
This archive:          57.16 MB           46.78 MB            151.67 kB  <--- !
All archives:         114.02 MB           93.46 MB             44.81 MB

For a graphical frontend refer to our complementary project BorgWeb.