Incremental Backup: Fast & Space-saving But Time-costing & Uneasy Restoration

Posted by @AOMEI

July 14, 2015

Incremental backup is a fast kind of backup and also space-saving and convenient, but when it comes to restoration, it is time-costing and uneasy.

What is incremental backup?

Be different from common full backup, incremental backup refers to the backup of the new-added or changed files compared with the latest backup which can be a full backup or an incremental backup. Next, an example will be borrowed to explain incremental backup.

Originally, there is only file1 (10GB) on C drive. Let us make a full backup of C drive without compression on Monday, thus we get an backup image1 (10GB).

Tuesday, we add a new file2 (5GB) to C drive. Then, if we still have a full backup of C drive without compression, we will get a total 15GB backup image2. As a result, we will have two backup images - image1 and image2, which total up to 25GB. However, in backup image2, there are 10GB data which are identical with backup image1. In this way, much space is wasted to store the repeated 10GB data. Luckily, we have incremental backup. If then we make an incremental backup of C drive, we will only get a 5GB backup image3.

On Wednesday, a new file3 (2GB) is added in C drive. Similarly, an incremental backup to C drive without compression brings only a 2GB backup image4 compared to a total 17GB full backup image5.

In such way, incremental backup is fully displayed.

Monday
(10GB File1)
Tuesday
(10GB File1 + 5GB File2)
Wednesday
(10GB File1 + 5GB File2 + 2GB File3)
Full BackupImage1 10GBImage3 15GBImage5 17GB
Incremental BackupImage2 10GBImage4 5GBImage6 2GB

Advantages of incremental backup

  • It is a fast backup.
  • Compared with full backup and differential backup, incremental backup is the fastest. Just as mentioned above, incremental backup only back up the newly added or changed content. Therefore, much time will be saved.

  • It is the most space-saving backup.
  • As analyzed above, for the second time backup, full backup needs another 15GB space to store its image file while incremental backup only requires extra 5GB room. Without doubt, incremental backup saves much more space!

  • It allows different version of storage for a file or folder.
  • In the example above, all the image files can be saved respectively in a file or folder. Thus, we can selectively choose one or more image files to do restoring work. It is very convenient for us users.

Disadvantages of incremental backup

  • It costs most time to restore our computers with the image files created through incremental backup.
  • Compared with other kinds of image files, those come from incremental backup requires most time. Since those image files are not stored in one backup, we have to restore them one by one. Therefore, much time will be spent on the work.

  • The image file that contains the related increments must be found before restoring a certain version.
  • Since every incremental image file is unique and it relates to a unique version, if we want to restore to a certain version, its related image file must be found first. If there are many incremental image files, that must be a hard work.

Software to do incremental backup

Most kinds of backup software can do incremental backup, such as AOMEI Backupper, which specially can merge all incremental backups with full backup, which saves much time when restore from incremental backup.

Incremental Backup

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