247 lines
7.6 KiB
ReStructuredText
247 lines
7.6 KiB
ReStructuredText
Tape Backup
|
|
===========
|
|
|
|
Our tape backup solution provides a easy way to store datastore
|
|
contents to a tape. This increases data safety because you get:
|
|
|
|
- an additional copy of the data
|
|
- to a different media type (tape)
|
|
- to an additional location (you can move tape offsite)
|
|
|
|
Statistics show that 95% of all restore jobs restores the last
|
|
backup. Restore requests further declines the older the data gets.
|
|
Considering that, tape backup may also help to reduce disk usage,
|
|
because you can safely remove data from disk once archived on tape.
|
|
This is especially true if you need to keep data for several years.
|
|
|
|
Tape backups do not provide random access to the stored data. Instead,
|
|
you need to restore the data to disk before you can access it
|
|
again. Also, if you store your tapes offsite (using some kind of tape
|
|
vaulting service), you need to bring them onsite before you can do any
|
|
restore. So please consider that restores from tapes can take much
|
|
longer than restores from disk.
|
|
|
|
|
|
Tape Technology Primer
|
|
----------------------
|
|
|
|
.. _Linear Tape Open: https://en.wikipedia.org/wiki/Linear_Tape-Open
|
|
|
|
As of 2021, the only broadly available tape technology standard is
|
|
`Linear Tape Open`_, and different vendors offers LTO Ultrium tape
|
|
drives, autoloaders and LTO tape cartridges.
|
|
|
|
Of cause, there are a few vendor offering proprietary drives with
|
|
slight advantages in performance and capacity, but they have
|
|
significat disadvantages:
|
|
|
|
- proprietary (single vendor)
|
|
- a much higher purchase cost
|
|
|
|
So we currently do no test such drives.
|
|
|
|
In general, LTO tapes offer the following advantages:
|
|
|
|
- Durable (30 years)
|
|
- High Capacity (12 TB)
|
|
- Relatively low cost per TB
|
|
- Cold Media
|
|
- Movable (storable inside vault)
|
|
- Multiple vendors (for both media and drives)
|
|
|
|
Please note that `Proxmox Backup Server`_ already stores compressed
|
|
data, so we do not need/use the tape compression feature. Same applies
|
|
to encryption.
|
|
|
|
|
|
Supported Hardware
|
|
------------------
|
|
|
|
Proxmox Backup Server supports `Linear Tape Open`_ genertion 3
|
|
(LTO3) or later. In general, all SCSI2 tape drives supported by
|
|
the Linux kernel should work.
|
|
|
|
Tape changer support is done using the Linux 'mtx' command line
|
|
tool. So any changer devive supported by that tool work work.
|
|
|
|
|
|
Drive Performance
|
|
~~~~~~~~~~~~~~~~~
|
|
|
|
Current LTO8 tapes provide read/write speeds up to 360MB/s. Please
|
|
note that it still takes a minimum of 9 hours to completely write or
|
|
read a single tape (even at maximum speed).
|
|
|
|
The only way to speed up that data rate is to use more than one
|
|
drive. That way you can run several backup jobs in parallel, or run
|
|
restore jobs while the other dives are used for backups.
|
|
|
|
Also consider that you need to read data first from your datastore
|
|
(disk). But a single spinning disk is unable to deliver data at this
|
|
rate. We meassured a maximum rate about 100MB/s in practive, so it
|
|
takes 33 hours to read 12TB to fill up a LTO8 tape. So if you want to
|
|
run your tape at full speed, please make sure that the source
|
|
datastore is able to delive that performance (use SSDs).
|
|
|
|
|
|
Terminology
|
|
-----------
|
|
|
|
:Tape Labels: are used to uniquely indentify a tape. You normally use
|
|
some sticky paper labels and apply them on the front of the
|
|
cartridge. We additionally store the label text magnetically on the
|
|
tape (first file on tape).
|
|
|
|
.. _Code 39: https://en.wikipedia.org/wiki/Code_39
|
|
|
|
.. _LTO Ultrium Cartridge Label Specification: https://www.ibm.com/support/pages/ibm-lto-ultrium-cartridge-label-specification
|
|
|
|
.. _LTO Barcode Generator: lto-barcode/index.html
|
|
|
|
:Barcodes: are a special form of tape labels, which are electronically
|
|
readable. Most LTO tape robots use an 8 character string encoded as
|
|
`Code 39`_, as definded in the `LTO Ultrium Cartridge Label
|
|
Specification`_.
|
|
|
|
You can either bye such barcode labels from your cartidge vendor,
|
|
or print them yourself. You can use our `LTO Barcode Generator`_ App
|
|
for that.
|
|
|
|
.. Note:: Physical labels and the associated adhesive shall have an
|
|
environmental performance to match or exceed the environmental
|
|
specifications of the cartridge to which it is applied.
|
|
|
|
:Media Pools: A media pool is a logical container for tapes. A backup
|
|
job targets one media pool, so a job only uses tapes from that
|
|
pool. The pool aditionally defines how long we can append data to a
|
|
tape (allocation policy), and how long we want to keep that data
|
|
(retention policy).
|
|
|
|
:Tape drive: The decive used to read and write data to the tape. There
|
|
are standalone drives, but drives often ship within tape libraries.
|
|
|
|
:Tape changer: A device which can change the tapes inside a tape drive
|
|
(tape robot). They are usually part of a tape library.
|
|
|
|
.. _Tape Library: https://en.wikipedia.org/wiki/Tape_library
|
|
|
|
:`Tape library`_: A storage device that contains one or more tape drives,
|
|
a number of slots to hold tape cartridges, a barcode reader to
|
|
identify tape cartridges and an automated method for loading tapes
|
|
(a robot).
|
|
|
|
People als call this 'autoloader', 'tape robot' or 'tape jukebox'.
|
|
|
|
|
|
Tape Quickstart
|
|
---------------
|
|
|
|
1. Configure your tape hardware (drives and changers)
|
|
|
|
2. Configure one or more media pools
|
|
|
|
3. Label your tape cartridges.
|
|
|
|
4. Start your first tape backup job ...
|
|
|
|
|
|
Configuration
|
|
-------------
|
|
|
|
Please note that you can configure anything using the graphical user
|
|
interface or the command line interface. Both methods results in the
|
|
same configuration.
|
|
|
|
|
|
Tape changers
|
|
~~~~~~~~~~~~~
|
|
|
|
Tape changers (robots) are part of a `Tape Library`_. You can skip
|
|
this step if you are using a standalone drive.
|
|
|
|
Linux is able to auto detect those devices, and you can get a list
|
|
of available devices using:
|
|
|
|
# proxmox-tape changer scan
|
|
|
|
In order to use that device with Proxmox, you need to create a
|
|
configuration entry:
|
|
|
|
# proxmox-tape changer create sl3 --path /dev/tape/by-id/scsi-CJ0JBE0059
|
|
|
|
Where ``sl3`` is an arbitrary name you can choose.
|
|
|
|
.. Note:: Please use stable device names from inside
|
|
``/dev/tape/by-id/``. Names like ``/dev/sg0`` may point to a
|
|
different device after reboot, and that is not what you want.
|
|
|
|
You can show the final configuration with:
|
|
|
|
# proxmox-tape changer list
|
|
|
|
The Vendor, Model and Serial number are auto detected, but only shown
|
|
if the device is online.
|
|
|
|
|
|
Tape drives
|
|
~~~~~~~~~~~
|
|
|
|
|
|
Media Pools
|
|
~~~~~~~~~~~
|
|
|
|
|
|
Tape Jobs
|
|
~~~~~~~~~
|
|
|
|
|
|
Administration
|
|
--------------
|
|
|
|
Label Tapes
|
|
~~~~~~~~~~~
|
|
|
|
By default, tape cartidges all looks the same, so you need to put a
|
|
label on them for unique identification. So first, put a sticky paper
|
|
label with some human readable text on the cartridge.
|
|
|
|
If you use a `Tape Library`_, you should use an 8 character string
|
|
encoded as `Code 39`_, as definded in the `LTO Ultrium Cartridge Label
|
|
Specification`_. You can either bye such barcode labels from your
|
|
cartidge vendor, or print them yourself. You can use our `LTO Barcode
|
|
Generator`_ App for that.
|
|
|
|
Next, you need to write that same label text to the tape, so that the
|
|
software can uniquely identify the tape too.
|
|
|
|
For a standalone drive, manually insert the new tape cartidge into the
|
|
drive and run:
|
|
|
|
# proxmox-tape label --changer-id <label-text> --drive <drive-name>
|
|
|
|
.. Note:: For safety reasons, this command fails if the tape contain
|
|
any data. If you want to overwrite it anways, erase the tape first.
|
|
|
|
You can verify success by reading back the label:
|
|
|
|
# proxmox-tape read-label --drive <drive-name>
|
|
|
|
If you have a tape library, apply the sticky barcode label to the tape
|
|
cartridges first. Then load those empty tapes into the library. You
|
|
can then label all unlabeled tapes with a single command:
|
|
|
|
# proxmox-tape barcode-label --drive <drive-name>
|
|
|
|
|
|
Run Tape Backups
|
|
~~~~~~~~~~~~~~~~
|
|
|
|
Restore from Tape
|
|
~~~~~~~~~~~~~~~~~
|
|
|
|
Update Inventory
|
|
~~~~~~~~~~~~~~~~
|
|
|
|
Restore Catalog
|
|
~~~~~~~~~~~~~~~
|