Disk Based Backups With Amanda On Debian Etch

This document describes how to set up Amanda (The Advanced Maryland Automatic Network Disk Archiver) on Debian Etch. For this tutorial I chose Ubuntu v7.04 as a backup-client. The resulting system provides a flexible backup-system with many features. It will be able to back up multiple hosts via network to various devices. I chose the disk based backup for this howto.

This howto is meant as a practical guide; it does not cover the theoretical backgrounds. They are treated in a lot of other documents in the web.

This document comes without warranty of any kind! I want to say that this is not the only way of setting up such a system. There are many ways of achieving this goal but this is the way I take. I do not issue any guarantee that this will work for you!

1 Preparation

Set up a basic Debian system and a basic Ubuntu system - update both.

The Debian system will be the backup-host: server1.example.com.

The Ubuntu system will be the backup-client: server2.example.com.

2 Needed Packages On The Backup-Host

apt-get install amanda-server xinetd gawk gnuplot readline-common

3 Backup-Host Configuration

Note: I'm using the standard configuration DailySet1 in this howto.

3.1 Amanda.conf

We customize the amanda.conf for DailySet1 to our needs:

vi /etc/amanda/DailySet1/amanda.conf

Edit the following, existing lines, so that they look like this:

tapecycle 6 tapes
tapetype DISK
tpchanger "chg-disk"
changerfile "/etc/amanda/DailySet1/changer"
tapedev "file:/dumps/amandatapes/DailySet1"

Now add the tapetype definition for the virtual tapedevice. In this example I chose a size of 3GB for each virtual tape - resulting in a required space of 18GB for all six virtual tapes. Adjust it to your needs.

define tapetype DISK {
 comment "Backup to HD"
 length 3072 mbytes
}

Next we have to add a dumptype where we define the settings for the backups. But of course you can use the existing dumptypes. Make sure that you use/create one with the entry program "GNUTAR". All possible settings are well commented in the amanda.conf.

define dumptype example {
 global
 comment "example dumptype"
 compress client fast
 program "GNUTAR"
 strategy standard
 priority high
}

3.2 Virtual Tapedevice

First we have to prepare a directory-tree for amanda where the backups will be stored temporarily (the holding disk):

mkdir -p /dumps/amanda

Now we have to create a directory for the virtual tapedevice:

mkdir -p /dumps/amandatapes/DailySet1

In the next step we have to create the directories for the virtual tapes. In this example we create six virtual tapes:

for i in 1 2 3 4 5 6; do mkdir /dumps/amandatapes/DailySet1/slot${i}; done

Create the info file:

touch /dumps/amandatapes/DailySet1/info

Time to initialize the tapedevice by inserting the first virtual tape into the tapedevice:

ln -s /dumps/amandatapes/DailySet1/slot1 /dumps/amandatapes/DailySet1/data

Now we have to pass the ownership to the amanda-user:

chown -R backup:backup /dumps/

Next we switch to the user backup:

su backup

Note: All amanda-commands, except amrestore, have to be executed as user backup.

Create the tapelist file:

touch /etc/amanda/DailySet1/tapelist

We have to label the virtual tapes to make them usable for amanda:

for i in 1 2 3 4 5 6; do /usr/sbin/amlabel DailySet1 DailySet1-${i} slot ${i}; done

3.3 The Disklist

The disklist brings all together. Here we define what has to be backed up from what server with which settings. A complete entry for a server consists of the fqdn, the path (e.g. /var) or device (e.g. sda1) that shall be backed up and the dumptype.

vi /etc/amanda/DailySet1/disklist

server2.example.com /home example

Note: Don't forget to add the backup-client to /etc/hosts if you are using this setup in a LAN without an own DNS.

3.4 Amandahosts

Finally we have to edit the amandahosts file:

vi /etc/amandahosts

server1.example.com backup
server1.example.com root
server2.example.com root

4 Needed Packages On the Backup-Client

sudo apt-get install amanda-client xinetd openssh-server

5 Amandahosts On The Backup-Client

Add the backup-host to the amandahosts file.

sudo vi /etc/amandahosts

server1.example.com backup

Note: Don't forget to add the backup-host to /etc/hosts if you are using this setup in a LAN without an own DNS.

6 Scheduled Backups

Modify the existing crontab (crontab.amanda) in /etc/amanda on the backup-host to your needs.

7 Testing The Configuration On The Backup Host

/usr/sbin/amcheck DailySet1

should look like:

Amanda Tape Server Host Check
-----------------------------
Holding disk /dumps/amanda: 25063520 KB disk space available, using 24961120 KB
slot 1: read label `DailySet1-1', date `20070911'
NOTE: skipping tape-writable test
Tape DailySet1-1 label ok
Server check took 0.254 seconds
Amanda Backup Client Hosts Check
--------------------------------
Client check: 1 host checked in 0.354 seconds, 0 problems found
(brought to you by Amanda 2.5.1p1)

8 Manual Backup

For testing purposes or special reasons you can make a backup manually of course:

/usr/sbin/amdump DailySet1

Note: Depending on the size of the data this could take a while.

9 Restore Backups

Switch to a directory on the backup-host where you (temporarily) want to restore the backup file(s):

cd /tmp/

9.1 Select The Virtual Tape

Insert the virtual tape from which you want to restore the backup(s):

/usr/sbin/amtape $configuration slot $x

e.g.

/usr/sbin/amtape DailySet1 slot 1

9.2 Rewind The Virtual Tape

No joke, you have to rewind your HD. :)

/usr/sbin/ammt -t file:/dumps/amandatapes/$configuration rewind

e.g.

/usr/sbin/ammt -t file:/dumps/amandatapes/DailySet1 rewind

9.3 Restore Backup(s) From The Virtual Tape

To get all backups from the tape:

/usr/sbin/amrestore file:/dumps/amandatapes/$configuration

e.g.

/usr/sbin/amrestore file:/dumps/amandatapes/DailySet1

To get a single backup from the tape:

/usr/sbin/amrestore file:/dumps/amandatapes/$configuration $host $backed_path_or_device

e.g.

/usr/sbin/amrestore file:/dumps/amandatapes/DailySet1 server2.example.com '/home$'

or

/usr/sbin/amrestore file:/dumps/amandatapes/DailySet1 server2.example.com sda1

9.4 Transfer The Backup-File To The Client Host

I chose scp for this.

scp -C $backup_file $user@$backup-client:$destination_file

e.g.

scp -C server2.example.com._home.20070911.0 administrator@server2.example.com:/tmp/backup

9.5 Uncompress The Transfered Backup On The Client-Host

cd /tmp/
sudo tar xvf backup