Backups on Debian Linux

Typically you will be backing up files and databases, these are some useful little shell scripts that I can never remember off the top of my head.

Requirements

• Command line access to your hosting, and the ability to login as root.
• You have some separate backup space mounted at /mnt/backup/
• You are using MySQL for the database (although I assume most have a similar command to ‘hotcopy’).

Backup databases

I have a file which includes several database backups like this WordPress example:

# Backup wordpress
rm -R /mnt/backups/wordpress/*;
mysqlhotcopy -u root --password=RootsPassWord wordpress /mnt/backups/wordpress/;
tar -cf /mnt/backups/wordpress/wordpress.tar  /mnt/backups/wordpress/*;
rm  /mnt/backups/wordpress/wordpress/wp*;
rmdir /mnt/backups/wordpress/wordpress/;
gzip /mnt/backups/wordpress/wordpress.tar;

This script:

1. Removes the previous copy.
2. Uses MySQL hotcopy to dump the database to files.
3. Copies the files into a tar ball.
4. Removes the files.
5. Removes the directory.
6. zips the tar file.

MySQL dump is another method, there’s a useful article on backing up with mysqldump.

Backup files

Rsync is a great utility, and after the first time it will only send across updates. At the end of the backup file I have this to backup the web site files:

rsync -av --exclude="cache" /home/username/www/* /mnt/backups/username/www/

The -a is for the ‘archive’ mode, and tries to maintain all the structures & permissions etc. The -v is for verbose, and you can remove this when you know it’s working ok.

The exclude line there means I don’t backup the cached copies of pages from wordpress or other items, which would quickly become a massive amout of files.

Automating the backups

You don’t want to have to remember to backup, and Debian provides some easy ways of regularly running scripts. I’ve tried adding things to my ‘crontab’, but it didn’t seem to work. I’ve found it best to just add things manually to the main crontab file.

As root, open the crontab file (/etc/crontab), and add the data here:

# m h dom mon dow user  command
10 3    * * 0   root    /path/to/YourBackupScript

That wil run at 3:10am each sunday, as root. Check your logs to see when things are quiet.

Restoring you data

Most backup pages I’ve come across don’t actually tell you how to restore your data! Trying not to fall into that trap, if everything goes pear-shaped and you have to restore something the process is simply to copy the file across, or for a database:

1. Login as root.
2. Find the current copy of the database, often in /var/lib/mysql/DatabaseName.
3. Stop MySQL (/etc/init.d/mysql stop).
4. Move the previous files (I would put them in my home directory for now).
5. Copy the backed up files into that directory. Go into that directory.
6. Correct the ownership: chown mysql.mysql *
7. Correct the permissions: chmod 660 *
8. Restart MySQL: /etc/init.d/mysql start

Wraping up

That is the basic building blocks of a back-up plan, if you’ve any questions, comments or improvements feel free to leave a comment below and I’ll update the page. For more advanced usage, there are some good ideas & scripts on the Bytemark forum.