mirror of https://github.com/borgbackup/borg.git
152 lines
4.4 KiB
ReStructuredText
152 lines
4.4 KiB
ReStructuredText
Welcome to Darc's documentation!
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================================
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Darc is a Deduplicating ARChiver written in Python.
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The main goal of Darc is to provide an efficient and secure way to backup data.
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Features
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--------
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Space efficient storage
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Variable block size `deduplication <http://en.wikipedia.org/wiki/Data_deduplication>`_
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is used to reduce the number of bytes stored by detecting redundant data.
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Each file is split into a number of variable length chunks and only chunks
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that have never been seen before are compressed and added to the repository.
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Secure
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All data is encrypted using `AES256 <http://en.wikipedia.org/wiki/Advanced_Encryption_Standard>`_
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and the data integrity and authenticity is verified using
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`HMAC-SHA256 <http://en.wikipedia.org/wiki/HMAC>`_.
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Remote repositories
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Darc can store data on remote hosts over SSH as long as Darc is installed on
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the remote host. The following syntax is used to specify a remote repository::
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$ darc list hostname:path
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$ darc extract hostname:path::archive-name
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$ darc extract username@hostname:path::archive-name
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Definitions
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-----------
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Deduplication
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Deduplication is a technique for improving storage utilization by eliminating
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redundant data.
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Archive
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A Darc archive is a collection of files along with metadata that include file
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permissions, directory structure and various file attributes.
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Repository
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A Darc repository is a filesystem directory storing data from zero or more archives.
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The data in a store is both deduplicated and encrypted making it both
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efficient and safe.
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Key file
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When a Darc store is initialized a key file containing a password protected
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encryption key is created. It is vital to keep this file safe since the store
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data is totally inaccessible without it.
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Requirements
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------------
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* Python >= 3.2
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* msgpack-python
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* pyxattr
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Installation
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------------
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The following instructions will install Darc in ``/usr/local/darc/`` without interfering
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with the rest of the system.
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1. Initialize a new python environment::
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$ virtualenv /usr/local/darc
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2. Extract the source code using GIT or a release tarball::
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$ mkdir /usr/local/darc/src/
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$ cd /usr/local/darc/src/
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$ tar -xvzf darc-x.y.tar.gz
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OR
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$ git clone git://github.com/jborg/darc.git
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3. Install Darc::
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$ cd darc-x.y/
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$ ../../bin/python setup.py install
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4. Add /usr/local/darc/bin to $PATH
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Basic Usage
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===========
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Initializing a store
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--------------------
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Before the first archive can be created a store needs to be initialized::
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$ darc init /data/my-backup.darc
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Initializing repository at "/data/my-backup.darc"
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Key file password (Leave blank for no password): *****
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Key file password again: *****
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Key file "/home/YOU/.darc/keys/data_my_backup_darc" created.
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Remember that this file (and password) is needed to access your data. Keep it safe!
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Archive creation
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----------------
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The following command will create a new archive called ``backup-2011-09-10`` containing
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all files in ``~/Documents`` and ``~/src``::
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$ darc create -v /data/my-backup.darc::backup-2011-09-10 ~/Documents ~/src
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Extract an archive
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------------------
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The following command will extract the archive ``backup-2011-09-10``::
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$ darc extract -v /data/my-backup.darc::backup-2011-09-10
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Delete an archive
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-----------------
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The following command will delete archive ``backup-2011-09-10``::
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$ darc delete /data/my-backup.darc::backup-2011-09-10
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List store contents
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-------------------
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The following command will list the names of all archives in the store::
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$ darc list /data/my-backup.darc
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backup-2011-09-09
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backup-2011-09-10
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...
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List archive contents
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---------------------
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The following command will list the contents of the ``backup-2011-09-10`` archive::
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$ darc list /data/my-backup.darc::backup-2011-09-10
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-rw-r--r-- YOU users 280 May 14 2010 home/YOU/Documents/something.txt
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-rw-r--r-- YOU users 280 May 14 2010 home/YOU/Documents/something-else.pdf
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...
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Prune old archives
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------------------
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When performing automatic backups it is important to periodically prune old backup
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archives to stop the store from growing too big.
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The following command will prune old archives and only keep the
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seven latest end of day archives and the five latest end of week archives::
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$ darc prune --daily=7 --weekly=5 /data/my-backup.darc
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Indices and tables
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==================
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* :ref:`genindex`
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* :ref:`search`
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