Clonezilla

Clonezilla's entire purpose is disk and partition imaging: cloning an entire drive to another drive, or creating a compressed image file of a system that can be restored later, driven through a straightforward text-based menu rather than a graphical desktop. It's used everywhere from IT departments imaging fleets of identical machines for fast deployment, to individual users making a full backup image before a risky upgrade, to system administrators migrating an installation to new hardware. Its 'Server Edition' variant supports multicasting an image to many machines simultaneously over a network, letting an entire computer lab or office get imaged in one pass rather than one machine at a time.