Differential Backup - Faster Backup & Restoration and Lower

December 25, 2014

Differential backup is a kind of backup features. Its backup speed, restoration speed and storage space requirement are all between full backup and incremental backup.

What is differential backup?

Differential backup, as can be inferred from its name, is a backup of the different parts. Here, the different parts are the new-added or changed parts compared with the last full backup. In order to make it easy to understand, an example will be displayed.

Originally, there is only a file1 (10GB) in D drive. On Monday, if we make a full backup of D drive without compression, then, we will get a backup image1 (10GB).

Tuesday, one file2 (5GB) is added into D drive. In such condition, if we still make a full backup of D drive without compression, we will get one backup image2 15GB. Actually, in the 15GB backup image2, there is 10GB data which is exactly the same as what in backup image1. If we save both backup image1 and backup image2, 10GB space will be wasted. Besides, the backup time of the repeated 10GB data is also unnecessary. Therefore, we can use differential backup. In this way, we will only get a 5GB backup image3.

On Wednesday, another file3 (2GB) is added to D drive. At this time, a differential backup to D drive only generates a 7GB backup image4 compared to a 17GB backup image5 of a full backup.

Like this, differential backup runs.

(10GB File1)
(10GB File1 + 5GB File2)
(10GB File1 + 5GB File2 + 2GB File3)
Full BackupImage1 10GBImage3 15GBImage5 17GB
Differential BackupImage2 10GBImage4 5GBImage6 7GB

Advantages of differential backup

  • Faster backup than full backup.
  • Lower storage space requirement than full backup.
  • Faster restoration than incremental backup.

Disadvantages of differential backup

  • Slower backup than incremental backup.
  • Higher storage space requirement than incremental backup.
  • Slower restoration than full backup.

Software to do differential backup

Most kinds of backup software can do differential backup, such as AOMEI Backupper.

Differential Backup

To learn how to do differential backup with AOMEI Backupper, please go to How to Do Incremental Backup and Differential Backup?