borg/docs/quickstart.rst

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.. include:: global.rst.inc
.. _quickstart:
Quick Start
===========
This chapter will get you started with |project_name|. The first section
presents a simple step by step example that uses |project_name| to backup data.
The next section continues by showing how backups can be automated.
A step by step example
----------------------
1. Before a backup can be made a repository has to be initialized::
$ attic init /somewhere/my-repository.attic
2. Backup the ``~/src`` and ``~/Documents`` directories into an archive called
*Monday*::
$ attic create -v /somwhere/my-repository.attic::Monday ~/src ~/Documents
3. The next day create a new archive called *Tuesday*::
$ attic create -v --stats /somwhere/my-repository.attic::Tuesday ~/src ~/Documents
This backup will be a lot quicker and a lot smaller since only new never
before seen data is stored. The ``--stats`` option causes |project_name| to
output statistics about the newly created archive such as the amount of unique
data (not shared with other archives)::
Archive name: Tuesday
Archive fingerprint: 387a5e3f9b0e792e91ce87134b0f4bfe17677d9248cb5337f3fbf3a8e157942a
Start time: Sun Apr 6 12:00:10 2014
End time: Sun Apr 6 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
4. List all archives in the repository::
$ attic list /somewhere/my-repository.attic
5. List the contents of the *Monday* archive::
$ attic list /somewhere/my-repository.attic::Monday
6. Restore the *Monday* archive::
$ attic extract -v /somwhere/my-repository.attic::Monday
7. Recover disk space by manually deleting the *Monday* archive::
$ attic delete /somwhere/my-backup.attic::Monday
Automating backups
------------------
The following example script backs up ``/home`` and
``/var/www`` to a remote server. The script also uses the
:ref:`attic_prune` subcommand to maintain a certain number
of old archives::
#!/bin/sh
REPOSITORY=username@remoteserver.com:repository.attic
# Backup all of /home and /var/www except a few
# excluded directories
attic create --stats \
$REPOSITORY::hostname-`date +%Y-%m-%d` \
/home \
/var/www \
--exclude /home/*/.cache \
--exclude /home/Ben/Music/Justin\ Bieber \
--exclude '*.pyc'
# Use the `prune` subcommand to maintain 7 daily, 4 weekly
# and 6 monthly archives.
attic prune -v $REPOSITORY --keep-daily=7 --keep-weekly=4 --keep-monthly=6
.. Note::
This script assumes the repository has already been initialized with
:ref:`attic_init`.
.. _encrypted_repos:
Repository encryption
---------------------
Repository encryption is enabled at repository creation time::
$ attic init --encryption=passphrase|keyfile PATH
When repository encryption is enabled all data is encrypted using 256-bit AES_
encryption and the integrity and authenticity is verified using `HMAC-SHA256`_.
All data is encrypted before being written to the repository. This means that
an attacker that manages to compromise the host containing an encrypted
archive will not be able to access any of the data.
|project_name| supports two different methods to derive the AES and HMAC keys.
Passphrase based encryption
This method uses a user supplied passphrase to derive the keys using the
PBKDF2_ key derivation function. This method is convenient to use since
there is no key file to keep track of and secure as long as a *strong*
passphrase is used.
.. Note::
For automated backups the passphrase can be specified using the
`ATTIC_PASSPHRASE` environment variable.
Key file based encryption
This method generates random keys at repository initialization time that
are stored in a password protected file in the ``~/.attic/keys/`` directory.
The key file is a printable text file. This method is secure and suitable
for automated backups.
.. Note::
The repository data is totally inaccessible without the key file
so it must be kept **safe**.
.. _remote_repos:
Remote repositories
-------------------
|project_name| can initialize and access repositories on remote hosts if the
host is accessible using SSH. This is fastest and easiest when |project_name|
is installed on the remote host, in which case the following syntax is used::
$ attic init user@hostname:repository.attic
or::
$ attic init ssh://user@hostname:port/repository.attic
If it is not possible to install |project_name| on the remote host,
it is still possible to use the remote host to store a repository by
mounting the remote filesystem, for example, using sshfs::
$ sshfs user@hostname:/path/to/folder /tmp/mymountpoint
$ attic init /tmp/mymountpoint/repository.attic
$ fusermount -u /tmp/mymountpoint
However, be aware that sshfs doesn't fully implement POSIX locks, so
you must be sure to not have two processes trying to access the same
repository at the same time.