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 --repo2 /srv/restic-repo-copy
    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 destination repository is specified with ``--repo2`` or can be read 
from a file specified via ``--repository-file2``. Both of these options
can also set as environment variables ``$RESTIC_REPOSITORY2`` or
``$RESTIC_REPOSITORY_FILE2`` respectively. For the destination repository 
the password can be read from a file ``--password-file2`` or from a command 
``--password-command2``.
Alternatively the environment variables ``$RESTIC_PASSWORD_COMMAND2`` and
``$RESTIC_PASSWORD_FILE2`` can be used. It is also possible to directly
pass the password via ``$RESTIC_PASSWORD2``. The key which should be used
for decryption can be selected by passing its ID via the flag ``--key-hint2``
or the environment variable ``$RESTIC_KEY_HINT2``.

.. 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.

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 --repo2 /srv/restic-repo-copy --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 --repo2 /srv/restic-repo-copy 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 --repo2 /srv/restic-repo --copy-chunker-params

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


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 range of pack files, the second selects a random
percentage of pack files, and the third selects pack files of the specified size.

Use ``--read-data-subset=n/t`` to check only a subset 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=n%`` to check a randomly choosen subset of the
repository pack files. It takes one parameter, ``n``, 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 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 (B/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