borg/docs/usage.rst

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.. include:: global.rst.inc
.. _detailed_usage:
Usage
=====
|project_name| consists of a number of commands. Each command accepts
a number of arguments and options. The following sections will describe each
command in detail.
Quiet by default
----------------
Like most UNIX commands |project_name| is quiet by default but the ``-v`` or
``--verbose`` option can be used to get the program to output more status
messages as it is processing.
Return codes
------------
|project_name| can exit with the following return codes (rc):
::
0 no error, normal termination
1 some error occurred (this can be a complete or a partial failure)
128+N killed by signal N (e.g. 137 == kill -9)
Note: we are aware that more distinct return codes might be useful, but it is
not clear yet which return codes should be used for which precise conditions.
See issue #61 for a discussion about that. Depending on the outcome of the
discussion there, return codes may change in future (the only thing rather sure
is that 0 will always mean some sort of success and "not 0" will always mean
some sort of warning / error / failure - but the definition of success might
change).
Environment Variables
---------------------
|project_name| uses some environment variables for automation:
::
Specifying a passphrase:
BORG_PASSPHRASE : When set, use the value to answer the passphrase question for encrypted repositories.
Some "yes" sayers (if set, they automatically confirm that you really want to do X even if there is that warning):
BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK : For "Warning: Attempting to access a previously unknown unencrypted repository"
BORG_RELOCATED_REPO_ACCESS_IS_OK : For "Warning: The repository at location ... was previously located at ..."
BORG_CHECK_I_KNOW_WHAT_I_AM_DOING : For "Warning: 'check --repair' is an experimental feature that might result in data loss."
Directories:
BORG_KEYS_DIR : Default to '~/.borg/keys'. This directory contains keys for encrypted repositories.
BORG_CACHE_DIR : Default to '~/.cache/borg'. This directory contains the local cache and might need a lot
of space for dealing with big repositories).
Building:
BORG_OPENSSL_PREFIX : Adds given OpenSSL header file directory to the default locations (setup.py).
General:
TMPDIR : where temporary files are stored (might need a lot of temporary space for some operations)
Please note:
- be very careful when using the "yes" sayers, the warnings with prompt exist for your / your data's security/safety
- also be very careful when putting your passphrase into a script, make sure it has appropriate file permissions
(e.g. mode 600, root:root).
Resource Usage
--------------
|project_name| might use a lot of resources depending on the size of the data set it is dealing with.
CPU: it won't go beyond 100% of 1 core as the code is currently single-threaded.
Especially higher zlib and lzma compression levels use significant amounts of CPU cycles.
Memory (RAM): the chunks index and the files index are read into memory for performance reasons.
compression, esp. lzma compression with high levels might need substantial amounts
of memory.
Temporary files: reading data and metadata from a FUSE mounted repository will consume about the same space as the
deduplicated chunks used to represent them in the repository.
Cache files: chunks index and files index (plus a compressed collection of single-archive chunk indexes).
Chunks index: proportional to the amount of data chunks in your repo. lots of small chunks in your repo implies a big
chunks index. you may need to tweak the chunker params (see create options) if you have a lot of data and
you want to keep the chunks index at some reasonable size.
Files index: proportional to the amount of files in your last backup. can be switched off (see create options), but
next backup will be much slower if you do.
Network: if your repository is remote, all deduplicated (and optionally compressed/encrypted) data of course has to go
over the connection (ssh: repo url). if you use a locally mounted network filesystem, additionally some copy
operations used for transaction support also go over the connection. if you backup multiple sources to one
target repository, additional traffic happens for cache resynchronization.
In case you are interested in more details, please read the internals documentation.
.. include:: usage/init.rst.inc
Examples
~~~~~~~~
::
# Local repository
$ borg init /mnt/backup
# Remote repository (accesses a remote borg via ssh)
$ borg init user@hostname:backup
# Encrypted remote repository, store the key in the repo
$ borg init --encryption=repokey user@hostname:backup
# Encrypted remote repository, store the key your home dir
$ borg init --encryption=keyfile user@hostname:backup
Important notes about encryption:
Use encryption! Repository encryption protects you e.g. against the case that
an attacker has access to your backup repository.
But be careful with the key / the passphrase:
``--encryption=passphrase`` is DEPRECATED and will be removed in next major release.
This mode has very fundamental, unfixable problems (like you can never change
your passphrase or the pbkdf2 iteration count for an existing repository, because
the encryption / decryption key is directly derived from the passphrase).
If you want "passphrase-only" security, just use the ``repokey`` mode. The key will
be stored inside the repository (in its "config" file). In above mentioned
attack scenario, the attacker will have the key (but not the passphrase).
If you want "passphrase and having-the-key" security, use the ``keyfile`` mode.
The key will be stored in your home directory (in ``.borg/keys``). In the attack
scenario, the attacker who has just access to your repo won't have the key (and
also not the passphrase).
Make a backup copy of the key file (``keyfile`` mode) or repo config file
(``repokey`` mode) and keep it at a safe place, so you still have the key in
case it gets corrupted or lost.
The backup that is encrypted with that key won't help you with that, of course.
Make sure you use a good passphrase. Not too short, not too simple. The real
encryption / decryption key is encrypted with / locked by your passphrase.
If an attacker gets your key, he can't unlock and use it without knowing the
passphrase. In ``repokey`` and ``keyfile`` modes, you can change your passphrase
for existing repos.
.. include:: usage/create.rst.inc
Examples
~~~~~~~~
::
# Backup ~/Documents into an archive named "my-documents"
$ borg create /mnt/backup::my-documents ~/Documents
# Backup ~/Documents and ~/src but exclude pyc files
$ borg create /mnt/backup::my-files \
~/Documents \
~/src \
--exclude '*.pyc'
# Backup the root filesystem into an archive named "root-YYYY-MM-DD"
NAME="root-`date +%Y-%m-%d`"
$ borg create /mnt/backup::$NAME / --do-not-cross-mountpoints
# Backup huge files with little chunk management overhead
$ borg create --chunker-params 19,23,21,4095 /mnt/backup::VMs /srv/VMs
# Backup a raw device (must not be active/in use/mounted at that time)
$ dd if=/dev/sda bs=10M | borg create /mnt/backup::my-sda -
# No compression (default)
$ borg create /mnt/backup::repo ~
# Super fast, low compression
$ borg create --compression lz4 /mnt/backup::repo ~
# Less fast, higher compression (N = 0..9)
$ borg create --compression zlib,N /mnt/backup::repo ~
# Even slower, even higher compression (N = 0..9)
$ borg create --compression lzma,N /mnt/backup::repo ~
.. include:: usage/extract.rst.inc
Examples
~~~~~~~~
::
# Extract entire archive
$ borg extract /mnt/backup::my-files
# Extract entire archive and list files while processing
$ borg extract -v /mnt/backup::my-files
# Extract the "src" directory
$ borg extract /mnt/backup::my-files home/USERNAME/src
# Extract the "src" directory but exclude object files
$ borg extract /mnt/backup::my-files home/USERNAME/src --exclude '*.o'
Note: currently, extract always writes into the current working directory ("."),
so make sure you ``cd`` to the right place before calling ``borg extract``.
.. include:: usage/check.rst.inc
.. include:: usage/delete.rst.inc
.. include:: usage/list.rst.inc
Examples
~~~~~~~~
::
$ borg list /mnt/backup
my-files Thu Aug 1 23:33:22 2013
my-documents Thu Aug 1 23:35:43 2013
root-2013-08-01 Thu Aug 1 23:43:55 2013
root-2013-08-02 Fri Aug 2 15:18:17 2013
...
$ borg list /mnt/backup::root-2013-08-02
drwxr-xr-x root root 0 Jun 05 12:06 .
lrwxrwxrwx root root 0 May 31 20:40 bin -> usr/bin
drwxr-xr-x root root 0 Aug 01 22:08 etc
drwxr-xr-x root root 0 Jul 15 22:07 etc/ImageMagick-6
-rw-r--r-- root root 1383 May 22 22:25 etc/ImageMagick-6/colors.xml
...
.. include:: usage/prune.rst.inc
Examples
~~~~~~~~
::
# Keep 7 end of day and 4 additional end of week archives:
$ borg prune /mnt/backup --keep-daily=7 --keep-weekly=4
# Same as above but only apply to archive names starting with "foo":
$ borg prune /mnt/backup --keep-daily=7 --keep-weekly=4 --prefix=foo
# Keep 7 end of day, 4 additional end of week archives,
# and an end of month archive for every month:
$ borg prune /mnt/backup --keep-daily=7 --keep-weekly=4 --keep-monthly=-1
# Keep all backups in the last 10 days, 4 additional end of week archives,
# and an end of month archive for every month:
$ borg prune /mnt/backup --keep-within=10d --keep-weekly=4 --keep-monthly=-1
.. include:: usage/info.rst.inc
Examples
~~~~~~~~
::
$ borg info /mnt/backup::root-2013-08-02
Name: root-2013-08-02
Fingerprint: bc3902e2c79b6d25f5d769b335c5c49331e6537f324d8d3badcb9a0917536dbb
Hostname: myhostname
Username: root
Time: Fri Aug 2 15:18:17 2013
Command line: /usr/bin/borg create --stats /mnt/backup::root-2013-08-02 / --do-not-cross-mountpoints
Number of files: 147429
Original size: 5344169493 (4.98 GB)
Compressed size: 1748189642 (1.63 GB)
Unique data: 64805454 (61.80 MB)
.. include:: usage/mount.rst.inc
Examples
~~~~~~~~
::
$ borg mount /mnt/backup::root-2013-08-02 /tmp/mymountpoint
$ ls /tmp/mymountpoint
bin boot etc lib lib64 mnt opt root sbin srv usr var
$ fusermount -u /tmp/mymountpoint
.. include:: usage/change-passphrase.rst.inc
Examples
~~~~~~~~
::
# Create a key file protected repository
$ borg init --encryption=keyfile /mnt/backup
Initializing repository at "/mnt/backup"
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Key file "/home/USER/.borg/keys/mnt_backup" created.
Keep this file safe. Your data will be inaccessible without it.
# Change key file passphrase
$ borg change-passphrase /mnt/backup
Enter passphrase for key file /home/USER/.borg/keys/mnt_backup:
New passphrase:
Enter same passphrase again:
Key file "/home/USER/.borg/keys/mnt_backup" updated
.. include:: usage/serve.rst.inc
Examples
~~~~~~~~
::
# Allow an SSH keypair to only run |project_name|, and only have access to /mnt/backup.
# This will help to secure an automated remote backup system.
$ cat ~/.ssh/authorized_keys
command="borg serve --restrict-to-path /mnt/backup" ssh-rsa AAAAB3[...]