145 lines
5.2 KiB
ReStructuredText
145 lines
5.2 KiB
ReStructuredText
Description
|
|
^^^^^^^^^^^
|
|
|
|
``pxar`` is a command line utility to create and manipulate archives in the
|
|
:ref:`pxar-format`.
|
|
It is inspired by `casync file archive format
|
|
<http://0pointer.net/blog/casync-a-tool-for-distributing-file-system-images.html>`_,
|
|
which caters to a similar use-case.
|
|
The ``.pxar`` format is adapted to fulfill the specific needs of the Proxmox
|
|
Backup Server, for example, efficient storage of hardlinks.
|
|
The format is designed to reduce storage space needed on the server by achieving
|
|
a high level of deduplication.
|
|
|
|
Creating an Archive
|
|
^^^^^^^^^^^^^^^^^^^
|
|
|
|
Run the following command to create an archive of a folder named ``source``:
|
|
|
|
.. code-block:: console
|
|
|
|
# pxar create archive.pxar /path/to/source
|
|
|
|
This will create a new archive called ``archive.pxar`` with the contents of the
|
|
``source`` folder.
|
|
|
|
.. NOTE:: ``pxar`` will not overwrite any existing archives. If an archive with
|
|
the same name is already present in the target folder, the creation will
|
|
fail.
|
|
|
|
By default, ``pxar`` will skip certain mountpoints and will not follow device
|
|
boundaries. This design decision is based on the primary use case of creating
|
|
archives for backups. It makes sense to not back up the contents of certain
|
|
temporary or system specific files.
|
|
To alter this behavior and follow device boundaries, use the
|
|
``--all-file-systems`` flag.
|
|
|
|
It is possible to exclude certain files and/or folders from the archive by
|
|
passing the ``--exclude`` parameter with ``gitignore``\-style match patterns.
|
|
|
|
For example, you can exclude all files ending in ``.txt`` from the archive
|
|
by running:
|
|
|
|
.. code-block:: console
|
|
|
|
# pxar create archive.pxar /path/to/source --exclude '**/*.txt'
|
|
|
|
Be aware that the shell itself will try to expand all of the glob patterns before
|
|
invoking ``pxar``.
|
|
In order to avoid this, all globs have to be quoted correctly.
|
|
|
|
It is possible to pass the ``--exclude`` parameter multiple times, in order to
|
|
match more than one pattern. This allows you to use more complex
|
|
file exclusion/inclusion behavior. However, it is recommended to use
|
|
``.pxarexclude`` files instead for such cases.
|
|
|
|
For example you might want to exclude all ``.txt`` files except for a specific
|
|
one from the archive. This is achieved via the negated match pattern, prefixed
|
|
by ``!``.
|
|
All the glob patterns are relative to the ``source`` directory.
|
|
|
|
.. code-block:: console
|
|
|
|
# pxar create archive.pxar /path/to/source --exclude '**/*.txt' --exclude '!/folder/file.txt'
|
|
|
|
.. NOTE:: The order of the glob match patterns matters as later ones override
|
|
previous ones. Permutations of the same patterns lead to different results.
|
|
|
|
``pxar`` will store the list of glob match patterns passed as parameters via the
|
|
command line, in a file called ``.pxarexclude-cli`` at the root of
|
|
the archive.
|
|
If a file with this name is already present in the source folder during archive
|
|
creation, this file is not included in the archive and the file containing the
|
|
new patterns is added to the archive instead, the original file is not altered.
|
|
|
|
A more convenient and persistent way to exclude files from the archive is by
|
|
placing the glob match patterns in ``.pxarexclude`` files.
|
|
It is possible to create and place these files in any directory of the filesystem
|
|
tree.
|
|
These files must contain one pattern per line, again later patterns win over
|
|
previous ones.
|
|
The patterns control file exclusions of files present within the given directory
|
|
or further below it in the tree.
|
|
The behavior is the same as described in :ref:`creating-backups`.
|
|
|
|
Extracting an Archive
|
|
^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
An existing archive, ``archive.pxar``, is extracted to a ``target`` directory
|
|
with the following command:
|
|
|
|
.. code-block:: console
|
|
|
|
# pxar extract archive.pxar /path/to/target
|
|
|
|
If no target is provided, the content of the archive is extracted to the current
|
|
working directory.
|
|
|
|
In order to restore only parts of an archive, single files, and/or folders,
|
|
it is possible to pass the corresponding glob match patterns as additional
|
|
parameters or to use the patterns stored in a file:
|
|
|
|
.. code-block:: console
|
|
|
|
# pxar extract etc.pxar /restore/target/etc --pattern '**/*.conf'
|
|
|
|
The above example restores all ``.conf`` files encountered in any of the
|
|
sub-folders in the archive ``etc.pxar`` to the target ``/restore/target/etc``.
|
|
A path to the file containing match patterns can be specified using the
|
|
``--files-from`` parameter.
|
|
|
|
List the Contents of an Archive
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
To display the files and directories contained in an archive ``archive.pxar``,
|
|
run the following command:
|
|
|
|
.. code-block:: console
|
|
|
|
# pxar list archive.pxar
|
|
|
|
This displays the full path of each file or directory with respect to the
|
|
archives root.
|
|
|
|
Mounting an Archive
|
|
^^^^^^^^^^^^^^^^^^^
|
|
|
|
``pxar`` allows you to mount and inspect the contents of an archive via _`FUSE`.
|
|
In order to mount an archive named ``archive.pxar`` to the mountpoint ``/mnt``,
|
|
run the command:
|
|
|
|
.. code-block:: console
|
|
|
|
# pxar mount archive.pxar /mnt
|
|
|
|
Once the archive is mounted, you can access its content under the given
|
|
mountpoint.
|
|
|
|
.. code-block:: console
|
|
|
|
# cd /mnt
|
|
# ls
|
|
bin dev home lib32 libx32 media opt root sbin sys usr
|
|
boot etc lib lib64 lost+found mnt proc run srv tmp var
|
|
|