System administration professionals and home users alike share a need for the ability to be able to quickly and reliably make one-to-one copies of entire disks, both for the purposes of backup and recovery, as well as the process of easing deployments and complete refresh repairs and upgrades of existing systems.
To do so, a disk cloning utility is a must, to make sure that you've got an exact, and uncorrupted, copy of your original disk. For many years, Norton Ghost (now a Symantec product) was a favorite tool among administrators and technicians seeking to clone a disk. But the market these days has widened, and many open source tools offer comparable and even superior performance.
Let's take a look at four such open source tools, each with a slightly different focus, that make disk cloning an easy task.
Clonezilla is an open source disk imaging and cloning tool built in two different editions, one for single machines and another designed to do dozens of computers at one time. It supports a wide variety of file systems, including most of the popular file systems for Linux, Windows, and MacOS. Parts of Clonezilla are essentially just wrappers around some of the other tools below, but this makes it an easier-to-use tool for those new to disk imaging. The single-machine version of the program is essentially a Linux live CD that puts a simple menu structure around common cloning and imaging tasks.
Clonezilla is written primarily in Perl, and the source code can be found on the project's homepage under a GPL version 2 license.
A more basic tool is dd, which has existed as a Unix and later a Linux command line tool for decades, which essentially performs raw writing from one location to another, and can be configured with a variety of options. If you're running a Linux machine, or a similar BSD system, chances are you already have dd installed: it is a part of the GNU coreutils.
You may have used dd before to create a live USB installer for your favorite Linux distribution, or to copy an operating system to an SD card for use on a Raspberry Pi. While little more than a simple terminal command, its simplicity means you can include dd in scripts to perform backups and restores in a more automated way, according to your exact needs.
You can find the source code to dd on the GNU FTP site, which is licensed under the GPL version 3.
The FOG Project provides a web-based tool for disk cloning, aimed at tying together a variety of open source tools to make it easy to provide image solutions for Windows, Linux, and Mac OS. It used PXE (Preboot eXecution Environment) booting to download a small Linux client and perform the imaging remotely, making it much easier to maintain a large batch of computers than by shuffling around manual disks.
We've covered FOG before in considerable detail, so if you're interested in learning more about how to use FOG, check out this tutorial.
Partimage is a Linux-based tool, commonly packaged for a live rescue CD, which supports a variety of partition types and has a relatively easy-to-use menu structure. It's a little bit less intuitive than Clonezilla, but it may work better for you in certain situations.
Partimage is licensed under the GPL version 2 and its C++ source code can be found on SourceForge.
These certainly aren't the only free and open source disk cloning tools out there. Wikipedia lists over a dozen others with an open source license, and there are certainly more than that out there hidden away across the Internet. Do you have a favorite tool for disk cloning, either one listed here or one we should have included? Let us know in the comments below.