Backup How-To's: Home Backup: Hard Disk Imaging and Cloning

Continuing on from the previous article of the "Backup How-To's" series, in this article we will learn about another approach to data backup called HDD image backup. Image-based backup is fundamentally different from files-based method and provides higher speed and accuracy of backups. However, it has its own disadvantages which we will discuss below.

Definition of Image Backup

The term "image backup" or "disk image" assumes a complete copy of a hard drive which is created on a sector-by-sector basis without querying the file system. Due to its nature, HDD imaging can be used to back up data that can't be accessed on a file level, e.g. boot records. Usually it is used to create a complete snapshot of a hard drive or disk partition and back it up as a whole.

System Backup

The first and probably the most important advantage of drive imaging is its capability to back up operating system. This is of great value in terms of protection against complete drive failure, because recovering a file backup implies correct functioning of the OS which in this case needs to be set up from scratch. Restoring an image backup allows bringing the system to a working state in a matter of minutes.

Program Backup

Another advantage of image-based backup is that it helps protecting programs installed in your system. If you're more or less experienced PC user, you must know that simple copying of program files from one computer to another doesn't guarantee that the program will work. At the same time, image backup includes absolutely all data and its restoration guarantees proper operation of all applications.

Advanced Usage of Image Backup

Disk imaging lies in the principle of all HDD cloning software. By making an image backup of one hard disk and restoring it to a different device, you receive a drive with absolutely similar contents. The same idea can be successfully applied if you need to set up multiple identical computers. If you enjoy testing different hardware, or if you are famous as a nerd-next-door who is always ready to help with computers, you will certainly find it of great usefulness.

Disadvantages of Image Backup

Unlike common file-based backup, drive imaging can be hardly used to back up specific files and folders. Since it doesn't query the file system, there is no way to differentiate which sectors are "important" for the user and which are not. Therefore, it has to be a full backup which costs more time and disk space.

In the next article: Files- and Drive-based Backup