There are many ways to backup Linux. There are different tools in the arsenal that you could use, such as tar, rcopy or some backup software. One tool I recently started using is called Clonezilla, a cloning software similar to the popular Norton Ghost for Windows systems.
Clonezilla allows you to backup and restore file systems by cloning file systems or devices as image files. Clonezilla comes in two versions: Clonezilla Live and Clonezilla SE (Server Edition). Clonezilla Live is suitable for single machine backup and restore.
While Clonezilla SE is for massive deployment, it can clone many (40 plus!) computers simultaneously. Clonezilla saves and restores only used blocks in the hard disk. I’m using Clonezilla Live since I don’t need to backup and restore multiple computers.
To get started, you will need to download the Clonezilla Live iso file. Create a bootable CD from the iso file. Once the boot CD is created, you need to boot up from the Clonezilla Live CD on the desktop you want to perform a backup.
I recommend using a secondary USB drive for storing the backup image files. It will serve as a repository for your backup images as well as a restore point for later on. For further instructions, follow these instructions for using Clonezilla Live.