restic/doc/045_working_with_repos.rst

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#########################
Working with repositories
#########################

Listing all snapshots
=====================

Now, you can list all the snapshots stored in the repository:

.. code-block:: console

    $ restic -r /srv/restic-repo snapshots
    enter password for repository:
    ID        Date                 Host    Tags   Directory
    ----------------------------------------------------------------------
    40dc1520  2015-05-08 21:38:30  kasimir        /home/user/work
    79766175  2015-05-08 21:40:19  kasimir        /home/user/work
    bdbd3439  2015-05-08 21:45:17  luigi          /home/art
    590c8fc8  2015-05-08 21:47:38  kazik          /srv
    9f0bc19e  2015-05-08 21:46:11  luigi          /srv

You can filter the listing by directory path:

.. code-block:: console

    $ restic -r /srv/restic-repo snapshots --path="/srv"
    enter password for repository:
    ID        Date                 Host    Tags   Directory
    ----------------------------------------------------------------------
    590c8fc8  2015-05-08 21:47:38  kazik          /srv
    9f0bc19e  2015-05-08 21:46:11  luigi          /srv

Or filter by host:

.. code-block:: console

    $ restic -r /srv/restic-repo snapshots --host luigi
    enter password for repository:
    ID        Date                 Host    Tags   Directory
    ----------------------------------------------------------------------
    bdbd3439  2015-05-08 21:45:17  luigi          /home/art
    9f0bc19e  2015-05-08 21:46:11  luigi          /srv

Combining filters is also possible.

Furthermore you can group the output by the same filters (host, paths, tags):

.. code-block:: console

    $ restic -r /srv/restic-repo snapshots --group-by host

    enter password for repository:
    snapshots for (host [kasimir])
    ID        Date                 Host    Tags   Directory
    ----------------------------------------------------------------------
    40dc1520  2015-05-08 21:38:30  kasimir        /home/user/work
    79766175  2015-05-08 21:40:19  kasimir        /home/user/work
    2 snapshots
    snapshots for (host [luigi])
    ID        Date                 Host    Tags   Directory
    ----------------------------------------------------------------------
    bdbd3439  2015-05-08 21:45:17  luigi          /home/art
    9f0bc19e  2015-05-08 21:46:11  luigi          /srv
    2 snapshots
    snapshots for (host [kazik])
    ID        Date                 Host    Tags   Directory
    ----------------------------------------------------------------------
    590c8fc8  2015-05-08 21:47:38  kazik          /srv
    1 snapshots


Copying snapshots between repositories
======================================

In case you want to transfer snapshots between two repositories, for
example from a local to a remote repository, you can use the ``copy`` command:

.. code-block:: console

    $ restic -r /srv/restic-repo-copy copy --from-repo /srv/restic-repo
    repository d6504c63 opened successfully, password is correct
    repository 3dd0878c opened successfully, password is correct

    snapshot 410b18a2 of [/home/user/work] at 2020-06-09 23:15:57.305305 +0200 CEST)
      copy started, this may take a while...
    snapshot 7a746a07 saved

    snapshot 4e5d5487 of [/home/user/work] at 2020-05-01 22:44:07.012113 +0200 CEST)
    skipping snapshot 4e5d5487, was already copied to snapshot 50eb62b7

The example command copies all snapshots from the source repository
``/srv/restic-repo`` to the destination repository ``/srv/restic-repo-copy``.
Snapshots which have previously been copied between repositories will
be skipped by later copy runs.

.. important:: This process will have to both download (read) and upload (write)
    the entire snapshot(s) due to the different encryption keys used in the
    source and destination repository. This *may incur higher bandwidth usage
    and costs* than expected during normal backup runs.

.. important:: The copying process does not re-chunk files, which may break
    deduplication between the files copied and files already stored in the
    destination repository. This means that copied files, which existed in
    both the source and destination repository, *may occupy up to twice their
    space* in the destination repository. See below for how to avoid this.

The source repository is specified with ``--from-repo`` or can be read
from a file specified via ``--from-repository-file``. Both of these options
can also be set as environment variables ``$RESTIC_FROM_REPOSITORY`` or
``$RESTIC_FROM_REPOSITORY_FILE``, respectively. For the destination repository
the password can be read from a file ``--from-password-file`` or from a command
``--from-password-command``.
Alternatively the environment variables ``$RESTIC_FROM_PASSWORD_COMMAND`` and
``$RESTIC_FROM_PASSWORD_FILE`` can be used. It is also possible to directly
pass the password via ``$RESTIC_FROM_PASSWORD``. The key which should be used
for decryption can be selected by passing its ID via the flag ``--from-key-hint``
or the environment variable ``$RESTIC_FROM_KEY_HINT``.

.. note:: In case the source and destination repository use the same backend,
    the configuration options and environment variables used to configure the
    backend may apply to both repositories – for example it might not be
    possible to specify different accounts for the source and destination
    repository. You can avoid this limitation by using the rclone backend
    along with remotes which are configured in rclone.

.. _copy-filtering-snapshots:

Filtering snapshots to copy
---------------------------

The list of snapshots to copy can be filtered by host, path in the backup
and/or a comma-separated tag list:

.. code-block:: console

    $ restic -r /srv/restic-repo-copy copy --from-repo /srv/restic-repo --host luigi --path /srv --tag foo,bar

It is also possible to explicitly specify the list of snapshots to copy, in
which case only these instead of all snapshots will be copied:

.. code-block:: console

    $ restic -r /srv/restic-repo-copy copy --from-repo /srv/restic-repo 410b18a2 4e5d5487 latest

Ensuring deduplication for copied snapshots
-------------------------------------------

Even though the copy command can transfer snapshots between arbitrary repositories,
deduplication between snapshots from the source and destination repository may not work.
To ensure proper deduplication, both repositories have to use the same parameters for
splitting large files into smaller chunks, which requires additional setup steps. With
the same parameters restic will for both repositories split identical files into
identical chunks and therefore deduplication also works for snapshots copied between
these repositories.

The chunker parameters are generated once when creating a new (destination) repository.
That is for a copy destination repository we have to instruct restic to initialize it
using the same chunker parameters as the source repository:

.. code-block:: console

    $ restic -r /srv/restic-repo-copy init --from-repo /srv/restic-repo --copy-chunker-params

Note that it is not possible to change the chunker parameters of an existing repository.


Removing files from snapshots
=============================

Snapshots sometimes turn out to include more files that intended. Instead of
removing the snapshots entirely and running the corresponding backup commands
again (which is not always practical after the fact) it is possible to remove
the unwanted files from affected snapshots by rewriting them using the
``rewrite`` command:

.. code-block:: console

    $ restic -r /srv/restic-repo rewrite --exclude secret-file
    repository c881945a opened (repository version 2) successfully, password is correct

    snapshot 6160ddb2 of [/home/user/work] at 2022-06-12 16:01:28.406630608 +0200 CEST)
    excluding /home/user/work/secret-file
    saved new snapshot b6aee1ff

    snapshot 4fbaf325 of [/home/user/work] at 2022-05-01 11:22:26.500093107 +0200 CEST)

    modified 1 snapshots

    $ restic -r /srv/restic-repo rewrite --exclude secret-file 6160ddb2
    repository c881945a opened (repository version 2) successfully, password is correct

    snapshot 6160ddb2 of [/home/user/work] at 2022-06-12 16:01:28.406630608 +0200 CEST)
    excluding /home/user/work/secret-file
    new snapshot saved as b6aee1ff

    modified 1 snapshots

The options ``--exclude``, ``--exclude-file``, ``--iexclude`` and
``--iexclude-file`` are supported. They behave the same way as for the backup
command, see :ref:`backup-excluding-files` for details.

It is possible to rewrite only a subset of snapshots by filtering them the same
way as for the ``copy`` command, see :ref:`copy-filtering-snapshots`.

By default, the ``rewrite`` command will keep the original snapshots and create
new ones for every snapshot which was modified during rewriting. The new
snapshots are marked with the tag ``rewrite`` to differentiate them from the
original, rewritten snapshots.

Alternatively, you can use the ``--forget`` option to immediately remove the
original snapshots. In this case, no tag is added to the new snapshots. Please
note that this only removes the snapshots and not the actual data stored in the
repository. Run the ``prune`` command afterwards to remove the now unreferenced
data (just like when having used the ``forget`` command).

In order to preview the changes which ``rewrite`` would make, you can use the
``--dry-run`` option. This will simulate the rewriting process without actually
modifying the repository. Instead restic will only print the actions it would
perform.


Checking integrity and consistency
==================================

Imagine your repository is saved on a server that has a faulty hard
drive, or even worse, attackers get privileged access and modify the
files in your repository with the intention to make you restore
malicious data:

.. code-block:: console

    $ echo "boom" > /srv/restic-repo/index/de30f3231ca2e6a59af4aa84216dfe2ef7339c549dc11b09b84000997b139628

Trying to restore a snapshot which has been modified as shown above
will yield an error:

.. code-block:: console

    $ restic -r /srv/restic-repo --no-cache restore c23e491f --target /tmp/restore-work
    ...
    Fatal: unable to load index de30f323: load <index/de30f3231c>: invalid data returned

In order to detect these things before they become a problem, it's a
good idea to regularly use the ``check`` command to test whether your
repository is healthy and consistent, and that your precious backup
data is unharmed. There are two types of checks that can be performed:

- Structural consistency and integrity, e.g. snapshots, trees and pack files (default)
- Integrity of the actual data that you backed up (enabled with flags, see below)

To verify the structure of the repository, issue the ``check`` command.
If the repository is damaged like in the example above, ``check`` will
detect this and yield the same error as when you tried to restore:

.. code-block:: console

    $ restic -r /srv/restic-repo check
    ...
    load indexes
    error: error loading index de30f323: load <index/de30f3231c>: invalid data returned
    Fatal: LoadIndex returned errors

If the repository structure is intact, restic will show that no errors were found:

.. code-block:: console

    $ restic -r /src/restic-repo check
    ...
    load indexes
    check all packs
    check snapshots, trees and blobs
    no errors were found

By default, the ``check`` command does not verify that the actual pack files
on disk in the repository are unmodified, because doing so requires reading
a copy of every pack file in the repository. To tell restic to also verify the
integrity of the pack files in the repository, use the ``--read-data`` flag:

.. code-block:: console

    $ restic -r /srv/restic-repo check --read-data
    ...
    load indexes
    check all packs
    check snapshots, trees and blobs
    read all data
    [0:00] 100.00%  3 / 3 items
    duration: 0:00
    no errors were found

.. note:: Since ``--read-data`` has to download all pack files in the
    repository, beware that it might incur higher bandwidth costs than usual
    and also that it takes more time than the default ``check``.

Alternatively, use the ``--read-data-subset`` parameter to check only a subset
of the repository pack files at a time. It supports three ways to select a
subset. One selects a specific part of pack files, the second and third
selects a random subset of the pack files by the given percentage or size.

Use ``--read-data-subset=n/t`` to check a specific part of the repository pack
files at a time. The parameter takes two values, ``n`` and ``t``. When the check
command runs, all pack files in the repository are logically divided in ``t``
(roughly equal) groups, and only files that belong to group number ``n`` are
checked. For example, the following commands check all repository pack files
over 5 separate invocations:

.. code-block:: console

    $ restic -r /srv/restic-repo check --read-data-subset=1/5
    $ restic -r /srv/restic-repo check --read-data-subset=2/5
    $ restic -r /srv/restic-repo check --read-data-subset=3/5
    $ restic -r /srv/restic-repo check --read-data-subset=4/5
    $ restic -r /srv/restic-repo check --read-data-subset=5/5

Use ``--read-data-subset=x%`` to check a randomly choosen subset of the
repository pack files. It takes one parameter, ``x``, the percentage of
pack files to check as an integer or floating point number. This will not
guarantee to cover all available pack files after sufficient runs, but it is
easy to automate checking a small subset of data after each backup. For a
floating point value the following command may be used:

.. code-block:: console

    $ restic -r /srv/restic-repo check --read-data-subset=2.5%

When checking bigger subsets you most likely want to specify the percentage
as an integer:

.. code-block:: console

    $ restic -r /srv/restic-repo check --read-data-subset=10%

Use ``--read-data-subset=nS`` to check a randomly chosen subset of the
repository pack files. It takes one parameter, ``nS``, where 'n' is a whole
number representing file size and 'S' is the unit of file size (K/M/G/T) of
pack files to check. Behind the scenes, the specified size will be converted
to percentage of the total repository size. The behaviour of the check command
following this conversion will be the same as the percentage option above. For
a file size value the following command may be used:

.. code-block:: console

    $ restic -r /srv/restic-repo check --read-data-subset=50M
    $ restic -r /srv/restic-repo check --read-data-subset=10G


Upgrading the repository format version
=======================================

Repositories created using earlier restic versions use an older repository
format version and have to be upgraded to allow using all new features.
Upgrading must be done explicitly as a newer repository version increases the
minimum restic version required to access the repository. For example the
repository format version 2 is only readable using restic 0.14.0 or newer.

Upgrading to repository version 2 is a two step process: first run
``migrate upgrade_repo_v2`` which will check the repository integrity and
then upgrade the repository version. Repository problems must be corrected
before the migration will be possible. After the migration is complete, run
``prune`` to compress the repository metadata. To limit the amount of data
rewritten in at once, you can use the ``prune --max-repack-size size``
parameter, see :ref:`customize-pruning` for more details.

File contents stored in the repository will not be rewritten, data from new
backups will be compressed. Over time more and more of the repository will
be compressed. To speed up this process and compress all not yet compressed
data, you can run ``prune --repack-uncompressed``. When you plan to create
your backups with maximum compression, you should also add the
``--compression max`` flag to the prune command. For already backed up data,
the compression level cannot be changed later on.