KurlesHS/restic
1
0
Fork 0
forked from TrueCloudLab/restic
Code Pull requests Activity
restic/doc/040_backup.rst

566 lines
24 KiB
ReStructuredText
Raw Blame History

..
Normally, there are no heading levels assigned to certain characters as the structure is
determined from the succession of headings. However, this convention is used in Python’s
Style Guide for documenting which you may follow:
# with overline, for parts
* for chapters
= for sections
- for subsections
^ for subsubsections
" for paragraphs
##########
Backing up
##########
Now we're ready to backup some data. The contents of a directory at a
specific point in time is called a "snapshot" in restic. Run the
following command and enter the repository password you chose above
again:
.. code-block:: console
$ restic -r /srv/restic-repo --verbose backup ~/work
open repository
enter password for repository:
password is correct
lock repository
load index files
start scan
start backup
scan finished in 1.837s
processed 1.720 GiB in 0:12
Files: 5307 new, 0 changed, 0 unmodified
Dirs: 1867 new, 0 changed, 0 unmodified
Added: 1.200 GiB
snapshot 40dc1520 saved
As you can see, restic created a backup of the directory and was pretty
fast! The specific snapshot just created is identified by a sequence of
hexadecimal characters, ``40dc1520`` in this case.
You can see that restic tells us it processed 1.720 GiB of data, this is the
size of the files and directories in ``~/work`` on the local file system. It
also tells us that only 1.200 GiB was added to the repository. This means that
some of the data was duplicate and restic was able to efficiently reduce it.
If you don't pass the ``--verbose`` option, restic will print less data. You'll
still get a nice live status display. Be aware that the live status shows the
processed files and not the transferred data. Transferred volume might be lower
(due to de-duplication) or higher.
On Windows, the ``--use-fs-snapshot`` option will use Windows' Volume Shadow Copy
Service (VSS) when creating backups. Restic will transparently create a VSS
snapshot for each volume that contains files to backup. Files are read from the
VSS snapshot instead of the regular filesystem. This allows to backup files that are
exclusively locked by another process during the backup.
By default VSS ignores Outlook OST files. This is not a restriction of restic
but the default Windows VSS configuration. The files not to snapshot are
configured in the Windows registry under the following key:
.. code-block:: console
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BackupRestore\FilesNotToSnapshot
For more details refer the official Windows documentation e.g. the article
``Registry Keys and Values for Backup and Restore``.
If you run the backup command again, restic will create another snapshot of
your data, but this time it's even faster and no new data was added to the
repository (since all data is already there). This is de-duplication at work!
.. code-block:: console
$ restic -r /srv/restic-repo backup --verbose ~/work
open repository
enter password for repository:
password is correct
lock repository
load index files
using parent snapshot d875ae93
start scan
start backup
scan finished in 1.881s
processed 1.720 GiB in 0:03
Files: 0 new, 0 changed, 5307 unmodified
Dirs: 0 new, 0 changed, 1867 unmodified
Added: 0 B
snapshot 79766175 saved
You can even backup individual files in the same repository (not passing
``--verbose`` means less output):
.. code-block:: console
$ restic -r /srv/restic-repo backup ~/work.txt
enter password for repository:
password is correct
snapshot 249d0210 saved
If you're interested in what restic does, pass ``--verbose`` twice (or
``--verbose=2``) to display detailed information about each file and directory
restic encounters:
.. code-block:: console
$ echo 'more data foo bar' >> ~/work.txt
$ restic -r /srv/restic-repo backup --verbose --verbose ~/work.txt
open repository
enter password for repository:
password is correct
lock repository
load index files
using parent snapshot f3f8d56b
start scan
start backup
scan finished in 2.115s
modified /home/user/work.txt, saved in 0.007s (22 B added)
modified /home/user/, saved in 0.008s (0 B added, 378 B metadata)
modified /home/, saved in 0.009s (0 B added, 375 B metadata)
processed 22 B in 0:02
Files: 0 new, 1 changed, 0 unmodified
Dirs: 0 new, 2 changed, 0 unmodified
Data Blobs: 1 new
Tree Blobs: 3 new
Added: 1.116 KiB
snapshot 8dc503fc saved
In fact several hosts may use the same repository to backup directories
and files leading to a greater de-duplication.
Now is a good time to run ``restic check`` to verify that all data
is properly stored in the repository. You should run this command regularly
to make sure the internal structure of the repository is free of errors.
File change detection
*********************
When restic encounters a file that has already been backed up, whether in the
current backup or a previous one, it makes sure the file's contents are only
stored once in the repository. To do so, it normally has to scan the entire
contents of every file. Because this can be very expensive, restic also uses a
change detection rule based on file metadata to determine whether a file is
likely unchanged since a previous backup. If it is, the file is not scanned
again.
Change detection is only performed for regular files (not special files,
symlinks or directories) that have the exact same path as they did in a
previous backup of the same location. If a file or one of its containing
directories was renamed, it is considered a different file and its entire
contents will be scanned again.
Metadata changes (permissions, ownership, etc.) are always included in the
backup, even if file contents are considered unchanged.
On **Unix** (including Linux and Mac), given that a file lives at the same
location as a file in a previous backup, the following file metadata
attributes have to match for its contents to be presumed unchanged:
* Modification timestamp (mtime).
* Metadata change timestamp (ctime).
* File size.
* Inode number (internal number used to reference a file in a filesystem).
The reason for requiring both mtime and ctime to match is that Unix programs
can freely change mtime (and some do). In such cases, a ctime change may be
the only hint that a file did change.
The following ``restic backup`` command line flags modify the change detection
rules:
* ``--force``: turn off change detection and rescan all files.
* ``--ignore-ctime``: require mtime to match, but allow ctime to differ.
* ``--ignore-inode``: require mtime to match, but allow inode number
and ctime to differ.
The option ``--ignore-inode`` exists to support FUSE-based filesystems and
pCloud, which do not assign stable inodes to files.
Note that the device id of the containing mount point is never taken into
account. Device numbers are not stable for removable devices and ZFS snapshots.
If you want to force a re-scan in such a case, you can change the mountpoint.
On **Windows**, a file is considered unchanged when its path, size
and modification time match, and only ``--force`` has any effect.
The other options are recognized but ignored.
Excluding Files
***************
You can exclude folders and files by specifying exclude patterns, currently
the exclude options are:
- ``--exclude`` Specified one or more times to exclude one or more items
- ``--iexclude`` Same as ``--exclude`` but ignores the case of paths
- ``--exclude-caches`` Specified once to exclude folders containing a special file
- ``--exclude-file`` Specified one or more times to exclude items listed in a given file
- ``--iexclude-file`` Same as ``exclude-file`` but ignores cases like in ``--iexclude``
- ``--exclude-if-present foo`` Specified one or more times to exclude a folder's content if it contains a file called ``foo`` (optionally having a given header, no wildcards for the file name supported)
- ``--exclude-larger-than size`` Specified once to excludes files larger than the given size
Please see ``restic help backup`` for more specific information about each exclude option.
Let's say we have a file called ``excludes.txt`` with the following content:
::
# exclude go-files
*.go
# exclude foo/x/y/z/bar foo/x/bar foo/bar
foo/**/bar
It can be used like this:
.. code-block:: console
$ restic -r /srv/restic-repo backup ~/work --exclude="*.c" --exclude-file=excludes.txt
This instructs restic to exclude files matching the following criteria:
* All files matching ``*.c`` (parameter ``--exclude``)
* All files matching ``*.go`` (second line in ``excludes.txt``)
* All files and sub-directories named ``bar`` which reside somewhere below a directory called ``foo`` (fourth line in ``excludes.txt``)
Patterns use `filepath.Glob <https://golang.org/pkg/path/filepath/#Glob>`__ internally,
see `filepath.Match <https://golang.org/pkg/path/filepath/#Match>`__ for
syntax. Patterns are tested against the full path of a file/dir to be saved,
even if restic is passed a relative path to save.
Environment variables in exclude files are expanded with `os.ExpandEnv
<https://golang.org/pkg/os/#ExpandEnv>`__, so ``/home/$USER/foo`` will be
expanded to ``/home/bob/foo`` for the user ``bob``. To get a literal dollar
sign, write ``$$`` to the file - this has to be done even when there's no
matching environment variable for the word following a single ``$``. Note
that tilde (``~``) is not expanded, instead use the ``$HOME`` or equivalent
environment variable (depending on your operating system).
Patterns need to match on complete path components. For example, the pattern ``foo``:
* matches ``/dir1/foo/dir2/file`` and ``/dir/foo``
* does not match ``/dir/foobar`` or ``barfoo``
A trailing ``/`` is ignored, a leading ``/`` anchors the pattern at the root directory.
This means, ``/bin`` matches ``/bin/bash`` but does not match ``/usr/bin/restic``.
Regular wildcards cannot be used to match over the directory separator ``/``.
For example: ``b*ash`` matches ``/bin/bash`` but does not match ``/bin/ash``.
For this, the special wildcard ``**`` can be used to match arbitrary
sub-directories: The pattern ``foo/**/bar`` matches:
* ``/dir1/foo/dir2/bar/file``
* ``/foo/bar/file``
* ``/tmp/foo/bar``
Spaces in patterns listed in an exclude file can be specified verbatim. That is,
in order to exclude a file named ``foo bar star.txt``, put that just as it reads
on one line in the exclude file. Please note that beginning and trailing spaces
are trimmed - in order to match these, use e.g. a ``*`` at the beginning or end
of the filename.
Spaces in patterns listed in the other exclude options (e.g. ``--exclude`` on the
command line) are specified in different ways depending on the operating system
and/or shell. Restic itself does not need any escaping, but your shell may need
some escaping in order to pass the name/pattern as a single argument to restic.
On most Unixy shells, you can either quote or use backslashes. For example:
* ``--exclude='foo bar star/foo.txt'``
* ``--exclude="foo bar star/foo.txt"``
* ``--exclude=foo\ bar\ star/foo.txt``
By specifying the option ``--one-file-system`` you can instruct restic
to only backup files from the file systems the initially specified files
or directories reside on. In other words, it will prevent restic from crossing
filesystem boundaries when performing a backup.
For example, if you backup ``/`` with this option and you have external
media mounted under ``/media/usb`` then restic will not back up ``/media/usb``
at all because this is a different filesystem than ``/``. Virtual filesystems
such as ``/proc`` are also considered different and thereby excluded when
using ``--one-file-system``:
.. code-block:: console
$ restic -r /srv/restic-repo backup --one-file-system /
Please note that this does not prevent you from specifying multiple filesystems
on the command line, e.g:
.. code-block:: console
$ restic -r /srv/restic-repo backup --one-file-system / /media/usb
will back up both the ``/`` and ``/media/usb`` filesystems, but will not
include other filesystems like ``/sys`` and ``/proc``.
.. note:: ``--one-file-system`` is currently unsupported on Windows, and will
cause the backup to immediately fail with an error.
Files larger than a given size can be excluded using the `--exclude-larger-than`
option:
.. code-block:: console
$ restic -r /srv/restic-repo backup ~/work --exclude-larger-than 1M
This excludes files in ``~/work`` which are larger than 1 MB from the backup.
The default unit for the size value is bytes, so e.g. ``--exclude-larger-than 2048``
would exclude files larger than 2048 bytes (2 kilobytes). To specify other units,
suffix the size value with one of ``k``/``K`` for kilobytes, ``m``/``M`` for megabytes,
``g``/``G`` for gigabytes and ``t``/``T`` for terabytes (e.g. ``1k``, ``10K``, ``20m``,
``20M``, ``30g``, ``30G``, ``2t`` or ``2T``).
Including Files
***************
The options ``--files-from``, ``--files-from-verbatim`` and ``--files-from-raw``
allow you to list files that should be backed up in a file, rather than on the
command line. This is useful when a lot of files have to be backed up that are
not in the same folder.
The argument passed to ``--files-from`` must be the name of a text file that
contains one pattern per line. The file must be encoded as UTF-8, or UTF-16
with a byte-order mark. Leading and trailing whitespace is removed from the
patterns. Empty lines and lines starting with a ``#`` are ignored.
The patterns are expanded, when the file is read, by the Go function
`filepath.Glob <https://golang.org/pkg/path/filepath/#Glob>`__.
The option ``--files-from-verbatim`` has the same behavior as ``--files-from``,
except that it contains literal filenames. It does expand patterns; filenames
are listed verbatim. Lines starting with a ``#`` are not ignored; leading and
trailing whitespace is not trimmed off. Empty lines are still allowed, so that
files can be grouped.
``--files-from-raw`` is a third variant that requires filenames to be terminated
by a zero byte (the NUL character), so that it can even handle filenames that
contain newlines or are not encoded as UTF-8 (except on Windows, where the
listed filenames must still be encoded in UTF-8).
This option is the safest choice when generating filename lists from a script.
Its file format is the output format generated by GNU find's ``-print0`` option.
All three arguments interpret the argument ``-`` as standard input.
In all cases, paths may be absolute or relative to ``restic backup``'s
working directory.
For example, maybe you want to backup files which have a name that matches a
certain regular expression pattern (uses GNU find):
.. code-block:: console
$ find /tmp/somefiles -regex PATTERN -print0 > /tmp/files_to_backup
You can then use restic to backup the filtered files:
.. code-block:: console
$ restic -r /srv/restic-repo backup --files-from-raw /tmp/files_to_backup
You can combine all three options with each other and with the normal file arguments:
.. code-block:: console
$ restic backup --files-from /tmp/files_to_backup /tmp/some_additional_file
$ restic backup --files-from /tmp/glob-pattern --files-from-raw /tmp/generated-list /tmp/some_additional_file
Comparing Snapshots
*******************
Restic has a `diff` command which shows the difference between two snapshots
and displays a small statistic, just pass the command two snapshot IDs:
.. code-block:: console
$ restic -r /srv/restic-repo diff 5845b002 2ab627a6
password is correct
comparing snapshot ea657ce5 to 2ab627a6:
C /restic/cmd_diff.go
+ /restic/foo
C /restic/restic
Files: 0 new, 0 removed, 2 changed
Dirs: 1 new, 0 removed
Others: 0 new, 0 removed
Data Blobs: 14 new, 15 removed
Tree Blobs: 2 new, 1 removed
Added: 16.403 MiB
Removed: 16.402 MiB
Backing up special items and metadata
*************************************
**Symlinks** are archived as symlinks, ``restic`` does not follow them.
When you restore, you get the same symlink again, with the same link target
and the same timestamps.
If there is a **bind-mount** below a directory that is to be saved, restic descends into it.
**Device files** are saved and restored as device files. This means that e.g. ``/dev/sda`` is
archived as a block device file and restored as such. This also means that the content of the
corresponding disk is not read, at least not from the device file.
By default, restic does not save the access time (atime) for any files or other
items, since it is not possible to reliably disable updating the access time by
restic itself. This means that for each new backup a lot of metadata is
written, and the next backup needs to write new metadata again. If you really
want to save the access time for files and directories, you can pass the
``--with-atime`` option to the ``backup`` command.
Reading data from stdin
***********************
Sometimes it can be nice to directly save the output of a program, e.g.
``mysqldump`` so that the SQL can later be restored. Restic supports
this mode of operation, just supply the option ``--stdin`` to the
``backup`` command like this:
.. code-block:: console
$ set -o pipefail
$ mysqldump [...] | restic -r /srv/restic-repo backup --stdin
This creates a new snapshot of the output of ``mysqldump``. You can then
use e.g. the fuse mounting option (see below) to mount the repository
and read the file.
By default, the file name ``stdin`` is used, a different name can be
specified with ``--stdin-filename``, e.g. like this:
.. code-block:: console
$ mysqldump [...] | restic -r /srv/restic-repo backup --stdin --stdin-filename production.sql
The option ``pipefail`` is highly recommended so that a non-zero exit code from
one of the programs in the pipe (e.g. ``mysqldump`` here) makes the whole chain
return a non-zero exit code. Refer to the `Use the Unofficial Bash Strict Mode
<http://redsymbol.net/articles/unofficial-bash-strict-mode/>`__ for more
details on this.
Tags for backup
***************
Snapshots can have one or more tags, short strings which add identifying
information. Just specify the tags for a snapshot one by one with ``--tag``:
.. code-block:: console
$ restic -r /srv/restic-repo backup --tag projectX --tag foo --tag bar ~/work
[...]
The tags can later be used to keep (or forget) snapshots with the ``forget``
command. The command ``tag`` can be used to modify tags on an existing
snapshot.
Space requirements
******************
Restic currently assumes that your backup repository has sufficient space
for the backup operation you are about to perform. This is a realistic
assumption for many cloud providers, but may not be true when backing up
to local disks.
Should you run out of space during the middle of a backup, there will be
some additional data in the repository, but the snapshot will never be
created as it would only be written at the very (successful) end of
the backup operation. Previous snapshots will still be there and will still
work.
Environment Variables
*********************
In addition to command-line options, restic supports passing various options in
environment variables. The following lists these environment variables:
.. code-block:: console
RESTIC_REPOSITORY_FILE Name of file containing the repository location (replaces --repository-file)
RESTIC_REPOSITORY Location of repository (replaces -r)
RESTIC_PASSWORD_FILE Location of password file (replaces --password-file)
RESTIC_PASSWORD The actual password for the repository
RESTIC_PASSWORD_COMMAND Command printing the password for the repository to stdout
RESTIC_KEY_HINT ID of key to try decrypting first, before other keys
RESTIC_CACHE_DIR Location of the cache directory
RESTIC_PROGRESS_FPS Frames per second by which the progress bar is updated
TMPDIR Location for temporary files
AWS_ACCESS_KEY_ID Amazon S3 access key ID
AWS_SECRET_ACCESS_KEY Amazon S3 secret access key
AWS_DEFAULT_REGION Amazon S3 default region
ST_AUTH Auth URL for keystone v1 authentication
ST_USER Username for keystone v1 authentication
ST_KEY Password for keystone v1 authentication
OS_AUTH_URL Auth URL for keystone authentication
OS_REGION_NAME Region name for keystone authentication
OS_USERNAME Username for keystone authentication
OS_USER_ID User ID for keystone v3 authentication
OS_PASSWORD Password for keystone authentication
OS_TENANT_ID Tenant ID for keystone v2 authentication
OS_TENANT_NAME Tenant name for keystone v2 authentication
OS_USER_DOMAIN_NAME User domain name for keystone authentication
OS_USER_DOMAIN_ID User domain ID for keystone v3 authentication
OS_PROJECT_NAME Project name for keystone authentication
OS_PROJECT_DOMAIN_NAME Project domain name for keystone authentication
OS_PROJECT_DOMAIN_ID Project domain ID for keystone v3 authentication
OS_TRUST_ID Trust ID for keystone v3 authentication
OS_APPLICATION_CREDENTIAL_ID Application Credential ID (keystone v3)
OS_APPLICATION_CREDENTIAL_NAME Application Credential Name (keystone v3)
OS_APPLICATION_CREDENTIAL_SECRET Application Credential Secret (keystone v3)
OS_STORAGE_URL Storage URL for token authentication
OS_AUTH_TOKEN Auth token for token authentication
B2_ACCOUNT_ID Account ID or applicationKeyId for Backblaze B2
B2_ACCOUNT_KEY Account Key or applicationKey for Backblaze B2
AZURE_ACCOUNT_NAME Account name for Azure
AZURE_ACCOUNT_KEY Account key for Azure
GOOGLE_PROJECT_ID Project ID for Google Cloud Storage
GOOGLE_APPLICATION_CREDENTIALS Application Credentials for Google Cloud Storage (e.g. $HOME/.config/gs-secret-restic-key.json)
RCLONE_BWLIMIT rclone bandwidth limit
See :ref:`caching` for the rules concerning cache locations when
``RESTIC_CACHE_DIR`` is not set.
The external programs that restic may execute include ``rclone`` (for rclone
backends) and ``ssh`` (for the SFTP backend). These may respond to further
environment variables and configuration files; see their respective manuals.
Exit status codes
*****************
Restic returns one of the following exit status codes after the backup command is run:
* 0 when the backup was successful (snapshot with all source files created)
* 1 when there was a fatal error (no snapshot created)
* 3 when some source files could not be read (incomplete snapshot with remaining files created)
Fatal errors occur for example when restic is unable to write to the backup destination, when
there are network connectivity issues preventing successful communication, or when an invalid
password or command line argument is provided. When restic returns this exit status code, one
should not expect a snapshot to have been created.
Source file read errors occur when restic fails to read one or more files or directories that
it was asked to back up, e.g. due to permission problems. Restic displays the number of source
file read errors that occurred while running the backup. If there are errors of this type,
restic will still try to complete the backup run with all the other files, and create a
snapshot that then contains all but the unreadable files.
One can use these exit status codes in scripts and other automation tools, to make them aware of
the outcome of the backup run. To manually inspect the exit code in e.g. Linux, run ``echo $?``.
View git blame Copy permalink