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.