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 + 5GB File2)
(10GB File1 + 5GB File2 + 2GB File3)
|Full Backup||Image1 10GB||Image3 15GB||Image5 17GB|
|Differential Backup||Image2 10GB||Image4 5GB||Image6 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.
To learn how to do differential backup with AOMEI Backupper, please go to How to Do Incremental Backup and Differential Backup?