How to back up hard drives for disaster recovery with Clonezilla

Clonezilla is a feature-rich and user-friendly disk cloning and backup software which is under GPL. Clonezilla provides a convenient interface for cloning a disk/partition to another local device, or archiving a cloned image to an external SSH/Samba/NFS server. This tutorial describes how to back up or restore hard drives with Clonezilla.