X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=docs%2Fhowto-filedriver.txt;h=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391;hb=d92f70685083588e2a7ce6bc312a735f6937b5a6;hp=0d3104733ca284fcb3aba593ab4e68108b376947;hpb=6c1f39091444e58c33362f0cc086375d9d273e77;p=debian%2Famanda diff --git a/docs/howto-filedriver.txt b/docs/howto-filedriver.txt index 0d31047..e69de29 100644 --- a/docs/howto-filedriver.txt +++ b/docs/howto-filedriver.txt @@ -1,434 +0,0 @@ - -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 - -Table of Contents - - - Introduction - - Possible_Uses - - Setup - - - Basics - - - Recovery - -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]