Overview

When you create a backup for data, generally, there are three types of backup images. Maybe you do not even notice, the backup type has been selected by default. To be specific, they are full backup, incremental backup, and differential backup.

In a nutshell, they are different but indivisible. Note that a full backup will be created firstly no matter which backup type you choose. Full backup is the basis of all backup types. Here is a simple understanding.

  • Full backup refers to back up files completely, each backup is a complete backup and can be restored separately.

  • Incremental backup means to backup files that are changed since the last backup (full or incremental). Recovery requires ALL linked incremental backups, and the full backup;

  • Differential backup means to backup files that are changed since the last full backup. Recovery requires the latest differential backup and the full backup;

It can be clearly understood from above that the difference between incremental and differential backup, which needs different backup basis and recovery requirements. Then, detailed information on these backup types will be introduced below.

What is Full Backup?

Full Backup

Full backup refers to creating a backup of all the valid data, whether it is newly added or exists for a long time. Full backup does not depend on the file’s Archive Attribute to decide which file should be backed up. During a full backup, all existing marks will be cleaned and be marked as “backed up”, i.e. clear Archive Attribute.

To create a full backup of selected files or applications means to create an identical duplication of these data at a particular time point. Therefore, with only one full backup, you can completely restore all data, which dramatically decrease the recovery time.

For instance, we’ll create a full system backup image using full backup software after installing an operating system. If the system is 12GB, all system files and applications will be backed up. We can easily perform a system restore using this full backup. This also applies to fully backing up a data partition, a file folder and the entire disk and so on.

How about the disadvantage? Full backup has a fatal disadvantage as well. To keep the backup up to date, it is unavoidable to create more than one full backup. In that case, many identical data will be backed up again, which is a waste of time and storage.

Luckily, the appearance of incremental and differential backup makes it possible to figure out all these problems.

What is Incremental Backup?

Incremental Backup

Incremental backup means backing up all changed data based on last backup (full backup or incremental backup). During an incremental backup, all marked files and folders will be backed up. It will clear file’s Archive Attribute as well.

Please note that the first incremental backup should be based on a full backup. Since incremental backup is created on the basis of last backup, there will be a mutual dependent relationship between them.

That is to say, with incremental backup software, each backup will create an image file of modified or new added files, and all of them are linked together. The deletion of a previous image file will make all the subsequent image files invalid.

Here is an example of creating incremental backup. Suppose that D Drive has data as follows:

File nameFile size
D:\file1.txt5GB
D:\file2.txt10GB

First, let's make a full backup of D Drive. And then there will be a 15GB image file: Full1.adi, which includes file1.txt and file2.txt.

Then, let's add two files, file3.txt and file4.txt to D Drive. Now D Drive will have the files as follows:

File nameFile size
D:\file1.txt5GB
D:\file2.txt10GB
D:\file3.txt2GB
D:\file4.txt1GB

If we make an incremental backup of drive D for this time, then only the new added files, file3.txt and file4.txt will be backed up and generated as Incr1.adi. Compared to the image file backed up before, there is not any change for file1.txt and file2.txt so that they will not be backed up.

If we add file5.txt and file6.txt, keep file1.txt to file4.txt unchanged, and run incremental backup again, only file5.txt and file6.txt will be backed up as Incr2.adi. Surely, if any file in file1-4.txt has changed, it will be backed up as well.

The biggest advantage of incremental backup is that there is no identical backup image created during the process, which is time-saving and storage-saving.

However, the restoring of incremental backup might be troublesome. You need to prepare last full backup (Full1.adi) as well as all subsequent incremental backups (Incr1.adi and Incr2.adi) and restore them in the order of back up time point. This inadvertently increases the recovery time. If you lost any of them, the recovery will not succeed.

What is Differential Backup?

Differential Backup

Differential backup will back up changed files based on the last full backup. This method also requires a full backup exists. All differential backups are based on the full backup, so they are relatively independent.

During a differential backup, only marked files and folders will be backed up and the Archive Attribute will be not be cleaned, i.e. these files will not be marked as “backed up” after the differential backup.

In terms of recovery, you just need last full backup and the latest differential backup. Here comes an example of creating differential backup with differential backup software.

Suppose that E Drive has the following data:

File nameFile size
E:\file1.txt2GB

The first job is to create a full backup of file1.txt to generate Full1.adi.

Then add file2.txt and file3.txt to E drive. Run differential backup, and you’ll get Diff1.adi that contains file2.txt and file3.txt.

Then add file4.txt and file5.txt to E drive, run differential backup, you’ll get Diff2.adi that contains file2-5.txt.

The theory is the same. It will backup changed files based on last full backup. In that case, if you lost Diff1.adi file, you can still restore all files using Full1.adi and Diff2.adi. This method requires more time on backing up yet it costs less time in recovery.

Free Incremental and Differential Backup Software

Software that supports full backup, incremental backup and differential backup can be called professional backup software. AOMEI Backupper Standard is such software that can create these three types of backup image perfectly.

In addition, it is a freeware which is compatible with all PCs including Windows 10, 8.1, 8, 7, Vista and XP. This incremental and differential backup software allows you to incremental backup HDD to external hard drive with ease.

There are two ways to create incremental and differential backup:

  • Manually create incremental or differential backup.

  • Create incremental or differential backup automatically with Schedule (Scheduled differential backup only supported in Professional or higher edition).

Following are the detailed steps of backing up system drive incrementally or differentially. In the first place, download this free incremental and differential backup software on your computer.

Tips: If you want to backup system to external device, please connect it to your computer in advance. Before creating an incremental or a differential backup, you should create a full backup.

Manually create incremental or differential backup

1. Click Backup and then System Backup.

System Backup

2. The system drive is selected by default. Click to choose a destination path.

Select Destination

3. Click Start Backup and a full backup of the system drive will be created.

4. After the backup finished, go to Home tab and you’ll find the system backup task you just created. Move over it and click Backup option in the middle. In the expanded menu, select Incremental Backup or Differential Backup.

Choose Incremental Backup

5. In the pop-up window, you can write some comments for distinguishing. Then, click OK to create incremental backup or differential backup.

Tips: This strategy is used to do incremental backup or differential backup for one time. To save your time, It is suggested to run incremental/differential backup in schedule. Otherwise, you need to repeat Step 4 and Step 5 manually every time you want to perform incremental/differential backup.

Create Incremental and Differential Backup Automatically

You could create a scheduled Incremental or Differential backup to automatically run the incremental and differential backup without human interaction.

The steps of scheduled incremental and differential backup is the approximant the same as the above steps, the only difference is setting up a Schedule option before clicking Start Backup, here it is:

1. Click Backup and then System Backup.

2. Select a destination for the system image file.

3. Hit on Schedule, Choose a mode: Daily, Weekly, or Monthly in General tab, Choose Incremental Backup (Default) or Differential Backup (Paid) in Advanced tab, click OK.

Schedule Settings

4. Press Start Backup button, and choose Add the schedule and start backup now or Only add the schedule to create incremental or differential backup automatically.

Start Backup Now

If you created a schedule incremental or differential backup, the first time created the backup is a full backup, then incremental or differential backup will be created at the subsequent time. For instance, if you set schedule backup at 6 p.m in daily mode, it will run full backup at 6 p.m of the first day and run incremental/differential backup at 6 p.m of the second day.

Besides, you have other options to manage full backup, incremental and differential backups during creation:

  • Options: you can password protect images (supported by Professional edition), compress and split images here.

  • Scheme: You can manage backup storage by deleting old backups automatically after upgrading to Professional edition.

  • After creating backups, you can check all backups in the path: Home > the specific backup task > Advanced > Locate Image.

  • To incremental backup files like documents, photos, or music, please try File Backup.

With the help of powerful incremental and differential backup software - AOMEI Backupper, you can easily create incremental and differential backups for saving time and space. To learn more about the differences between incremental backup and differential backup in backup speed, storage and restore speed, please visit: incremental vs differential backup.