e87e4499fd
The s/Namesapce/Namespace/ one was reported in the forum [0] and so I figured I do a quick scan for others too using codespell. [0]: https://forum.proxmox.com/threads/109724/post-472744 Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
133 lines
3.6 KiB
ReStructuredText
133 lines
3.6 KiB
ReStructuredText
.. _terms:
|
|
|
|
Terminology
|
|
===========
|
|
|
|
Backup Content
|
|
--------------
|
|
|
|
When doing deduplication, there are different strategies to get
|
|
optimal results in terms of performance and/or deduplication rates.
|
|
Depending on the type of data, it can be split into *fixed* or *variable*
|
|
sized chunks.
|
|
|
|
Fixed sized chunking requires minimal CPU power, and is used to
|
|
backup virtual machine images.
|
|
|
|
Variable sized chunking needs more CPU power, but is essential to get
|
|
good deduplication rates for file archives.
|
|
|
|
The Proxmox Backup Server supports both strategies.
|
|
|
|
|
|
Image Archives: ``<name>.img``
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
This is used for virtual machine images and other large binary
|
|
data. Content is split into fixed-sized chunks.
|
|
|
|
|
|
File Archives: ``<name>.pxar``
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
.. see https://moinakg.wordpress.com/2013/06/22/high-performance-content-defined-chunking/
|
|
|
|
A file archive stores a full directory tree. Content is stored using
|
|
the :ref:`pxar-format`, split into variable-sized chunks. The format
|
|
is optimized to achieve good deduplication rates.
|
|
|
|
|
|
Binary Data (BLOBs)
|
|
~~~~~~~~~~~~~~~~~~~
|
|
|
|
This type is used to store smaller (< 16MB) binary data such as
|
|
configuration files. Larger files should be stored as image archives.
|
|
|
|
.. caution:: Please do not store all files as BLOBs. Instead, use the
|
|
file archive to store entire directory trees.
|
|
|
|
|
|
Catalog File: ``catalog.pcat1``
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
The catalog file is an index for file archives. It contains
|
|
the list of included files and is used to speed up search operations.
|
|
|
|
|
|
The Manifest: ``index.json``
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
The manifest contains a list of all backed up files, and their
|
|
sizes and checksums. It is used to verify the consistency of a
|
|
backup.
|
|
|
|
Backup Namespace
|
|
----------------
|
|
|
|
Namespaces allow for the reuse of a single chunk store deduplication domain for
|
|
multiple sources, while avoiding naming conflicts and getting more fine-grained
|
|
access control.
|
|
|
|
Essentially they're implemented as simple directory structure and need no
|
|
separate configuration.
|
|
|
|
Backup Type
|
|
-----------
|
|
|
|
The backup server groups backups by *type*, where *type* is one of:
|
|
|
|
``vm``
|
|
This type is used for :term:`virtual machine<Virtual machine>`\ s. It
|
|
typically consists of the virtual machine's configuration file and an image
|
|
archive for each disk.
|
|
|
|
``ct``
|
|
This type is used for :term:`container<Container>`\ s. It consists of the
|
|
container's configuration and a single file archive for the filesystem's
|
|
contents.
|
|
|
|
``host``
|
|
This type is used for file/directory backups created from within a machine.
|
|
Typically this would be a physical host, but could also be a virtual machine
|
|
or container. Such backups may contain file and image archives; there are no
|
|
restrictions in this regard.
|
|
|
|
Backup ID
|
|
---------
|
|
|
|
A unique ID for a specific Backup Type and Backup Namespace. Usually the
|
|
virtual machine or container ID. ``host`` type backups normally use the
|
|
hostname.
|
|
|
|
Backup Time
|
|
-----------
|
|
|
|
The time when the backup was made with second resolution.
|
|
|
|
|
|
Backup Group
|
|
------------
|
|
|
|
The tuple ``<type>/<id>`` is called a backup group. Such a group may contain
|
|
one or more backup snapshots.
|
|
|
|
|
|
.. _term_backup_snapshot:
|
|
|
|
Backup Snapshot
|
|
---------------
|
|
|
|
The triplet ``<type>/<ID>/<time>`` is called a backup snapshot. It
|
|
uniquely identifies a specific backup within a datastore.
|
|
|
|
.. code-block:: console
|
|
:caption: Backup Snapshot Examples
|
|
|
|
vm/104/2019-10-09T08:01:06Z
|
|
host/elsa/2019-11-08T09:48:14Z
|
|
|
|
As you can see, the time format is RFC3339_ with Coordinated
|
|
Universal Time (UTC_, identified by the trailing *Z*).
|
|
|
|
|