+++ /dev/null
----
-
- AMANDA FILE-DRIVER-USAGE HOWTO.
-
----
-
- This document covers the use of the file-driver in AMANDA
- 2.4.3 and higher. Examples given here have been taken from a
- SuSe-Linux-8.2-Pro-environment, using AMANDA 2.4.4p1 and the
- snapshot 2.4.4p1-20031202.
-
- Please adjust paths, configuration names and other parameters
- to your system.
-
- Stefan G. Weichinger, November - December, 2003
-
----
-
- Since release 2.4.3 AMANDA supports the usage of a output
- driver called "file". See the AMANDA-man page, section
- OUTPUT DRIVERS, for more information on its implementation.
- As the name suggests, this driver uses files as virtual (or file)
- tapes. Once created and labeled, these file tapes can be selected
- and changed with the standard tape-changer-interface of the AMANDA
- server.
-
----
-
-POSSIBLE USES
-
----
-
- - test installations.
- You can easily explore the rich features of AMANDA on
- systems without tape drives.
-
- - cheap installations.
- Without buying a tape drive you can enjoy the benefits
- of AMANDA and backup to a bunch of harddisks. You can
- create CD/DVD-sized backups which you can burn onto optical
- disks later.
-
- - raid installations.
- You can use the file-driver to backup onto a set of
- file tapes hosted on a raid-system. Combined with
- another AMANDA-configuration that dumps the file tapes to
- real tapes, you can provide reliable backup with faster
- tapeless recovery.
-
----
-
-SETUP
-
----
-
-BASICS
-
- This guide assumes you have setup the basic AMANDA-services
- as described in the "INSTALL"-file.
-
- The configuration in this HOWTO is called "daily".
- The file tapes are also called "vtapes" in this document, which
- stands for "virtual tapes".
-
- Please be sure to understand the differences between holding disks and
- file tapes. The two serve different purposes; holding disks allow for
- parallelism of multiple DLE's being backed up while file tapes are a
- replacement for physical tapes.
-
- Before beginning you will need to decide on (a) dedicated part(s)
- of your hard disk(s) for your file tape storage. While this space
- could be spread among several file systems and hard disks, I
- recommend to dedicate at least a specific partition, better a specific
- physical harddisk to the task of keeping your vtapes.
- The use of a dedicated disk will speed things up definitely.
-
- The disk space you dedicate for your vtapes should NOT
- be backed up by AMANDA. Also, for performance reasons there
- should be NO holding disks on the same partition as the
- vtapes, preferably not even on the same physical drive.
-
- If you only have one harddisk, it will work out, too, but
- you will suffer low performance due to massive head-moving
- in your harddisk, resulting from copying data between the
- filesystems.
-
----
-
-STEPS
-
-Step 0. Prepare the filesystem(s) used for the tapes.
-
- Decide on where to put your files, create the
- appropriate partition(s) and filesystem(s) and mount them.
-
- In our example we have the dedicated partition "hdc1",
- mounted on /amandatapes for vtape storage.
-
- $ mount
- ...
- /dev/hdc1 on /amandatapes type reiserfs (rw)
- ...
-
- Make sure there is space left.
- Determine the amount of space you will use.
-
- $ df -h /amandatapes
- Filesystem Size Used Avail Use% Mounted on
- /dev/hdc1 20G 0G 20G 0% /amandatapes
-
- In our example we have 20GB diskspace left on /amandatapes.
-
-Step 1. Determine length and number of tapes
-
- After deciding on the number of vtapes you want to create,
- evenly allocate the available space among them.
-
- Look at the following rule of thumb:
-
- As many types file systems exhibit dramatically reduced performance
- when they are nearly full I have chosen to allocate
- only 90% of the available space. So we have:
-
- (Available Space * 0.9) >= tapelength * tapecycle
-
-
- This is a very conservative approach to make sure you don´t suffer
- any performance drop due to a nearly-full-filesystem.
-
- As it is uncommon for AMANDA to fill, or almost fill an entire tape
- you may also wish to use more space than that.
-
- So you could determine possible combinations of tapelength/tapecycle
- with the more general formula:
-
- Available Space >= tapelength * tapecycle
-
-
- In our example we take the conservative approach:
-
- 20 GB * 0.9 = 18 GB to use and so we could create the
- following combinations:
-
- 18 GB = 18 GB * 1
- 18 GB = 9 GB * 2
- 18 GB = 6 GB * 3
- 18 GB = 3 GB * 6
- 18 GB = ......... you get the picture.
-
- Using only one tape is generally considered a bad idea
- when it comes to backup, so we should use at least 3
- tapes (for testing purposes), better 6 or more tapes.
-
- 18 GB = 3 GB * 6 so we get the value 3GB for the
- tapelength if we want to use 6 tapes.
-
-Step 2. Create a tapetype definition.
-
- Add a new tapetype definition similar to the following to your amanda.conf.
- I named my definition "HARD-DISK". Choose whatever name you
- consider appropriate.
-
- define tapetype HARD-DISK {
- comment "Dump onto hard disk"
- length 3072 mbytes # specified in mbytes to get the exact size of 3GB
- }
-
- You don´t have to specify the "speed"-parameter (as it is
- commonly listed in tapetype definitions and reported by
- the program "amtapetype"). AMANDA does not use this parameter.
-
- There is also an optional "filemark"-parameter, which indicates
- the amount of space wasted after each tape-section. Leave it
- blank and AMANDA uses the default of 1KB.
-
-Step 3. Think about tapechangers.
-
- As you will use a set of vtapes, you have to also use a kind of vtape-changer.
- There are several tape-changer-scripts included in the AMANDA-tarball.
- Read more about tape-changer-scripts in TAPE.CHANGERS.
-
- Right now there are two scripts that can be used with vtapes.
- These scripts take different approaches to the handling of tapes.
-
- The script chg-multi handles many drives with a tape in each drive.
- The script chg-disk handles a library with one drive and multiple tapes.
-
- So with vtapes you could look at it this way:
-
- chg-multi simulates multiple tape drives with one tape in each drive.
- chg-disk simulates one tape-library with multiple tapes in.
-
- As chg-multi exists for a much longer time than chg-disk, it is still
- used in many AMANDA-vtape-installations.
-
- chg-disk was introduced with the snapshot 20031202.
- Contrary to chg-multi, which is a generic changer-script that must
- be somewhat adjusted to the use of the file-driver, chg-disk offers
- exactly the behavior needed for handling vtapes
-
- IMHO the approach is much more logical, so I recommend to use chg-disk
- in new AMANDA-vtape-installations.
-
- To use chg-disk you need to have at least amanda-2.4.4p1-20031202.
-
- Choose the one that fits your way of vtape-handling and -maintenance.
-
- In this HOWTO I only cover the use of chg-disk.
- Usage of chg-multi is pretty similar and will maybe covered in a later
- version of this document.
-
-Step 4. Set up your tape-config.
-
- In the general section you have to set the parameters tapecycle,
- tapetype, tpchanger, changerfile, tapedev, rawtapedev and changerdev.
-
- Example:
-
- $ vi /usr/local/etc/amanda/daily/amanda.conf
- ...
-
- tapecycle 6
- tapetype HARD-DISK
- tpchanger "chg-disk"
- changerfile "/usr/local/etc/amanda/daily/changer"
- tapedev "file:/amandatapes/daily"
-
- This reflects the use of your defined tapetype.
-
- The "tapecycle"-parameter tells AMANDA how much tapes can be used.
- Set this value according to the number of tapes you want to use.
-
- The "tapetype"-parameter points to the tapetype definition you have
- created in Step 2.
-
- The "tpchanger"-parameter tells AMANDA to use the generic
- tape-changer-script to handle the virtual tapes. You
- can think of it as a virtual tape-changer-device.
-
- The "changerfile"-parameter is used to give chg-disk the "prefix"
- for the "%s-changer, %s-clean, %s-slot" files it needs.
- Use something like "changer" in your config-dir.
- Please note that this file does NOT have to exist, but it won't
- hurt anyway.
-
- The "tapedev"-parameter tells the chg-disk-script where the
- root-dir for your vtapes is.
- In our example the vtape-files go to
- /amandatapes, and to separate multiple configurations we decided
- to use subdirectories according to the configuration name "daily".
-
-Step 5. Create the virtual tapes.
-
- Now you have to create the tape-directories.
- chg-disk needs a directory structure like:
-
- slot_root_dir -|
- |- info
- |- data -> slot1/
- |- slot1/
- |- slot2/
- |- ...
- |- slotn/
-
- where 'slot_root_dir' is the tapedev 'file:xxx' parameter
- and 'n' is the tapecycle parameter.
-
- So in our example we do:
-
- $ mkdir /amandatapes/daily
-
- for the 'slot_root_dir' and
-
- $ mkdir /amandatapes/daily/slot1
- $ mkdir /amandatapes/daily/slot2
- ....
-
- for the virtual slots that will later contain the vtapes.
-
- If you have many vtapes to create and their names follow a pattern
- you may be able to do them all with a single loop such as:
-
- $ for n in 1 2 3 4 5 6 7 8 9 10 11 12
- > do
- > mkdir /amandatapes/daily/slot${n}
- > done
-
- Create the info-file:
-
- $ touch /amandatapes/daily/info
-
- and link the first slot to the data-file (to "load" the vtape
- in the first slot):
-
- $ ln -s /amandatapes/daily/slot1 /amandatapes/daily/data
-
- Make sure the AMANDA-user has write-permissions on these directories:
-
- $ chown -R <amanda_user> /amandatapes
- $ chgrp -R <amanda_group> /amandatapes
- $ chmod -R 750 /amandatapes
-
-Step 8. Label the virtual tapes.
-
- As the virtual tapes are handled just like physical
- tapes by the AMANDA-Server they have to be labeled
- before use.
-
- Usage: amlabel [-f] <conf> <label> [slot <slot-number>]
-
- Example:
-
- $ amlabel daily daily1 slot 1
- ....
- $ amlabel daily daily2 slot 2
- ....
-
- If you have many vtapes to label and their names follow a pattern
- you may be able to do them all with a single loop such as:
-
- $ for n in 01 02 03 04 05 06 07 08 09 10 11 12
- > do
- > amlabel daily daily${n} slot ${n}
- > done
-
- Label all your created tapes according to the
- "labelstr"-parameter in your amanda.conf. Consult the
- amlabel-man-page for details.
-
-Step 9. Test your setup with amcheck.
-
- Run amcheck daily (or, more general, amcheck <config>)
- and look for anything AMANDA complains about.
-
- A proper output looks like:
-
- $ amcheck daily
- Amanda Tape Server Host Check
- -----------------------------
- Holding disk /amhold: 6924940 KB disk space available,
- that's plenty
- amcheck-server: slot 2: date 20031115 label daily02
- (exact label match)
- NOTE: skipping tape-writable test
- Tape daily02 label ok
- Server check took 0.377 seconds
-
- Recheck your files if errors occur.
-
-----
-
-
-THAT'S IT! YOU ARE READY TO RUN, UNLESS WE FORGOT
-SOMETHING. PLEASE send mail to amanda-users@amanda.org if
-you have any comments or questions. We're not afraid of
-negative reviews, so let us have it!
projects / debian / amanda / blobdiff