Full Disk Backup vs Data Backup

There are two distinct types of full-disk backups; one is a backup of every file on the disk, and the other is an image backup of your disk. The biggest difference comes at restore time. Lets take a few minutes and look at the advantages and disadvantages of the two types of full-disk backups and also data-only backups.

Disk Image Backup

Advantages: Can completely restore your entire hard drive in the event of a failure. Disk image backup software often provides a method for creating bootable media. This is the fastest way to get your computer back up and running after a catastrophic hard drive failure.

Disadvantages: Media requirements can be excessive, especially with the large hard drives that are available today. It can also be very difficult to keep your disk image backups current because of the time needed to backup the entire hard drive. However, some image backup software allows for the images to be updated incrementally. This saves time, but it can create multiple physical media sets that must be kept up with in order to do a complete restore. While restoring an entire disk image is an excellent recovery option when the disk drive itself fails, it is not so useful for recovering from a destroyed or stolen computer. Disk images need to be restored to the same or very similar computer hardware. If your computer needs to be replaced, it is highly unlikely that you will end up with the same hardware.

Full-Disk Backups

Advantages: Every file is backed up. Very little effort or expertise is needed when deciding what to backup.

Disadvantages: Media requirements can be excessive, especially with large hard drives. System files and program files are often in use or locked so that backing them up causes errors or other problems. Restoring of system files and program files is usually not recommended because components get out of sync causing unpredictable results.

Data-Only Backups

Advantages: Significantly less media requirements. Faster than full-disk or image backups. Can be easily used to recover important data after replacing a hard drive or an entire computer.

Disadvantages: After a hard drive or computer replacement, the operating system and programs need to be reinstalled before the data backups can be used. The correct files must be selected for backup, however, this is less of a problem on modern operating system because the store documents in a common location by default (My Documents).


Both types of full-disk backups require significant media and therefor more time to create and keep updated. As a result, full-disk backups are usually not performed as often as data-only backups. In the event of a catastrophe, it is likely that the full-disk backup will be outdated, requiring more current data to be restored after the restoration of the disk itself. This multi-step process and additional effort required to make the backups and store them offsite defeats part of the purpose for using them in the first place.

Data-only backups are fast and can easily be completely automated and stored offsite with a good online backup service. Data-only backups require extra effort to reinstall the operating system and programs, but the result is usually a very clean and trouble free system after the recovery. If you are using data-only backups, be sure to keep copies of your operating system and software media in a place where you can access them in case of an emergency.

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