--- /dev/null
+
+Chapter 13. How to use the AMANDA file-driver
+Prev Part III. HOWTOs Next
+
+-------------------------------------------------------------------------------
+
+Chapter 13. How to use the AMANDA file-driver
+
+
+Stefan G. Weichinger
+
+Original text;XML-conversion;Updates
+AMANDA Core Team
+<sgw@amanda.org>
+Table of Contents
+
+
+ Introduction
+
+ Possible_Uses
+
+ Setup
+
+
+ Basics
+
+
+ Recovery
+
+
+Note
+
+Refer to http://www.amanda.org/docs/howto-filedriver.html for the current
+version of this document.
+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 ; minor updates in April, 2005.
+
+Introduction
+
+Since release 2.4.3 AMANDA supports the usage of a output driver called "file".
+See man amanda, 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.
+* disk-based installations
+ You can use the file-driver to backup onto a set of file tapes hosted on a
+ bunch of hard-disks or 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. This is called "disk-to-disk-
+ to-tape"-backup by some people today.
+
+
+ Setup
+
+
+ Basics
+
+This guide assumes you have setup the basic AMANDA-services as described in
+Amanda_Installation_Notes
+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
+
+ 1. 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.
+ 2. 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 filesystems 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 3 GB for the tapelength if we want to use 6 tapes.
+
+ 3. 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 parameter speed (as it is commonly listed in
+ tapetype definitions and reported by the program amtapetype). AMANDA does
+ not use this parameter right now.
+ There is also an optional parameter filemark, which indicates the amount
+ of space "wasted" after each tape-listitem. Leave it blank and AMANDA uses
+ the default of 1KB.
+ 4. 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 AMANDA_Tape_Changer
+ Support.
+ 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.
+
+ Note
+
+ 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.
+ 5. 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 parameter tapecycle tells AMANDA how much tapes can be used, Set this
+ value according to the number of tapes you want to use.
+ The parameter tapetype , points to the tapetype definition you have
+ created before.
+ The parameter tpchanger tells AMANDA to use the generic tape-changer-
+ script to handle the vtapes. You can think of it as a virtual tape-
+ changer-device.
+ The parameter changerfile 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 parameter tapedev tells the chg-disk-script where the root-dir for
+ your vtapes is.
+ In our example the vtape-files go to /amandatapes.
+ To separate multiple configurations, we decided to use subdirectories
+ according to the configuration name "daily".
+
+ Note
+
+ The parameter changerdev is NOT needed with chg-disk as it is not parsed
+ by chg-disk.
+ 6. Create the virtual tapes.
+
+ Note
+
+ Gene Heskett has committed a shell-script which creates and labels the
+ vtapes in one step. Stefan G. Weichinger will generalize this script and
+ contribute it, this script will just read your settings in amanda.conf and
+ create the appropriate vtape-directories.
+ 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 into 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
+
+
+ 7. 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 1 2 3 4 5 6 7 8 9 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.
+ 8. 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.
+
+
+ Recovery
+
+Recovering files from vtapes is very similar to recovering files from a "real"
+tapechanger.
+Make sure you read the chapter Restore.
+I will simply paste a amrecover-session here (provided by JC Simonetti, author
+of chg-disk):
+
+ # /usr/local/amanda/sbin/amrecover woo
+ AMRECOVER Version 2.4.4p3. Contacting server on backupserver.local ...
+ 220 backupserver AMANDA index server (2.4.4p3) ready.
+ 200 Access OK
+ Setting restore date to today (2004-10-08)
+ 200 Working date set to 2004-10-08.
+ Scanning /BACKUP2/holding...
+ Scanning /BACKUP/holding...
+ 200 Config set to woo.
+ 200 Dump host set to backupserver.local.
+ Trying disk /tmp ...
+ $CWD '/tmp/RECOVER' is on disk '/tmp' mounted at '/tmp'.
+ 200 Disk set to /tmp.
+ Invalid directory - /tmp/RECOVER
+ amrecover> sethost backupserver.local
+ 200 Dump host set to backupserver.local.
+ amrecover> setdisk /
+ 200 Disk set to /.
+ amrecover> cd /etc
+ /etc
+ amrecover> add passwd
+ Added /etc/passwd
+ amrecover> list
+ TAPE B3_14 LEVEL 0 DATE 2004-09-26
+ /etc/passwd
+ amrecover> extract
+
+ Extracting files using tape drive file:/BACKUP2/slots/ on host
+ backupserver.local. The following tapes are needed: B3_14
+
+ Restoring files into directory /tmp/RECOVER
+ Continue [?/Y/n]? Y
+
+ Extracting files using tape drive file:/BACKUP2/slots/ on host
+ backupserver.local. Load tape B3_14 now
+ Continue [?/Y/n/s/t]? Y
+ ./etc/passwd
+ amrecover> quit
+ 200 Good bye.
+
+Nothing spectacular? The trick is this:
+When AMANDA asks you
+
+ Load tape B3_14 now Continue [?/Y/n/s/t]?
+
+you have to run the following in a second terminal:
+
+ $ amtape woo slot 14
+ amtape: changed to slot 14 on file:/BACKUP2/slots/
+
+This step is necessary to load the proper tape into your virtual changer.
+Let me express this in a more general way:
+When amrecover prompts for the tape it needs to restore the files you
+requested, you have to "load" the tape it requests.
+The recommended way to do this is to use amtape. The options that make sense in
+this context are:
+
+ # amtape
+ Usage: amtape <conf> <command>
+ Valid commands are:
+ [...]
+ slot <slot #> load tape from slot <slot #>
+ [...]
+ label <label> find and load labeled tape
+ [...]
+
+
+If you know which slot contains the requested tape (for example, if you have
+tape daily01 in slot 1, tape daily02 in slot 2, and so on) you may use the
+first option. If you just know the label of the tape you need, use the second
+option.
+To continue the upper example:
+
+ amtape woo slot 14 # option 1 OR
+ amtape woo label B3_14 # option 2
+
+amtape will return something like:
+
+ amtape: label B3_14 is now loaded.
+
+After this you can return to your amrecover-session and continue restoring your
+files.
+Please be aware of the fact reported by JC Simonetti: " I have never never used
+the "settape" command of amrecover [with chg-disk] since there's some problems
+with it (tape not loaded correctly, or impossible to change from tape to tape
+when restoring data shared accross multiple tapes...) "
+-------------------------------------------------------------------------------
+
+Prev Up Next
+Chapter 12. AMANDA on Cygwin HOWTO Home Chapter 14. AFS HOWTO
+
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