Save Much Disk Space: Incremental vs. Differential Backup

Overview of 3 Backup Types

When creating a backup for data, there are generally three types of backup images:full backup, incremental backup, and differential backup.

In a nutshell, they are different but indivisible. Note that A full backup will be created first, regardless of the type of backup 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.

The difference between incremental and differential backup lies in their backup basis and recovery requirements, with incremental backup focusing on backing up only changed files. If you're interested in learning the detailed steps of this process, you can continue reading, but if you'd like to delve deeper into the specifics of these backup methods, you can skip the step-by-step guide and proceed with further reading.

How to Backup Only Changed Files with Incremental Backup (3 Steps)

Software that supports full backup, incremental backup, and differential backup can be called professional backup software. Qiling Disk Master Standard is an example of such software, capable of creating these three types of backup images, and supports various backup types including System Backup, Disk Backup, Partition Backup, and File Backup, compatible with Windows operating systems from XP to Windows 11.

By default, it backs up only changed files with an incremental backup, but you can upgrade to differential backup if needed. This includes all changes since the last full backup, reducing the risk of data loss, and for recovery, you only need one full backup and the latest differential backup.

To create an incremental backup, you have two options: In the first place, download this free incremental backup software on your computer. For server users, try Qiling Disk Master Server.

• Manually create incremental backup.
• Create incremental backup automatically.

• Free Download
• Windows 11/10/8/7, 100% Secure

When creating a backup, whether incremental or differential, the first backup will be a full backup. Let's consider a system backup as an example to illustrate the process.
1. Launch Qiling Disk Master Standard, click Backup and then System Backup.

2. The system drive is selected by default, but you can change it by clicking the folder-shaped button.choose a destination path.

3. Click Schedule Backup > Enable Schedule Backup and choose Daily, Weekly, Monthly schedule backup. Afterward, click Proceed and Add the schedule and Proceed now.

The system will automatically create a full system image backup and then 6 incremental backups by default, allowing for customization of the number of incremental backups in the Backup Scheme.

The schedule backup will run a full backup at 6 p.m. on the first day and incremental/differential backups at 6 p.m. on subsequent days.

The default backup method can be changed to differential backup by selecting it and clicking OK. However, this feature is only available on the professional version, prompting the user to upgrade.

In addition to incremental or differential backups, you can also set up automatic backup cleanup to remove old backup images on a regular schedule through the Backup Scheme. This can be done by quantity, time, or frequency (daily, weekly, monthly).

Besides Schedule Backup and Backup Scheme, you can also password protect images, compress and split images, etc in the Backup Options.

While automated incremental backups are convenient, they can be inconvenient to set up and may require manual intervention at other times, such as after a backup or at a specific time.

• Go to the Backup and recovery tab, select the backup task you want to set for incremental backup.
• To create an incremental backup, click the Backup button, then select Incremental Backup from the dropdown menu. Alternatively, you can choose Differential Backup.

• Then, you will see the Comment window, write some comments for clear distinguish and click OK to start incremental backup. Next, you will see the Backup window, where you can choose the backup location, file name, and other options. After that, the backup process will start, and you will see the progress in the Backup window.

You can restore your system at any time using a backup image. To do so without booting into Windows, you can create bootable media with a USB or CD/DVD, or create a recovery environment that allows you to boot your computer from it, adding a boot menu to your current computer without needing any storage device.

 Full vs Incremental vs Differential: Advantages and Disadvantages

If you're still unsure about choosing a backup type, you can continue reading to learn more about incremental and differential backups. Once you've selected one, you can go back to the step-by-step guide and create a backup.

★ Full Backup Advantages and Disadvantages

A full backup is a complete copy of all valid data, including both new and existing data, created to ensure that all information is preserved in case of data loss or system failure.A full backup does not rely on the file's Archive Attribute to determine which files to include in the backup. Instead, it typically includes all files and folders in the specified backup scope, regardless of their Archive Attribute status.During a full backup, all existing marks will be cleared and marked as "backed up", effectively removing their 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, allowing for a complete restoration of all data with just one backup.dramatically decreases the recovery time.

To create a full system backup image, we use full backup software after installing an operating system, such as backing up a 12GB system with all system files and applications. This allows for a complete system restore using the full backup, and can also be applied to backing up a data partition, a file folder, or the entire disk.

Full backup has a fatal disadvantage: to keep the backup up to date, it is unavoidable to constantly overwrite the backup with new data, which can lead to data loss if something goes wrong during the overwrite process. create more than one full backupwaste of resources. This is especially true for large datasets, where the redundant data can take up a lot of storage space. To avoid this, you can use a technique called "delta encoding" which involves only storing the differences between successive data points, rather than the entire dataset.waste of time and storage.

The emergence of incremental and differential backup has provided a solution to the problems associated with traditional full backups.

★ Incremental Backup Advantages and Disadvantages 

Incremental backup involves backing up all changed data based on the last backup, whether it was a full backup or an incremental backup. During this process, all marked files and folders will be backed up, and the file's Archive Attribute will also be cleared.

The first incremental backup should be based on a full backup, as it relies on the last backup to create the incremental backup, creating a mutual dependent relationship between them.

That is to say, with incremental backup software, Each backup will create an image file of only the modified or newly added files, rather than a full image of the entire system. This approach helps to reduce the size of the backup and makes it more efficient to store and transfer., and all of them are linked together. Deleting a previous image file can render subsequent image files invalid, as they may rely on the deleted file for reference or context..

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

FirstLet's make a full backup of your D Drive. Once the backup is complete, you'll have a 15GB image file that contains a snapshot of your entire D Drive, including all files, folders, and settings. This will provide a complete and reliable copy of your D Drive, which you can use for disaster recovery, data migration, or simply as a safeguard against accidental data loss.Full1.fvd, which includes file1.txt and file2.txt.

ThenTo add two files, file3.txt and file4.txt to D Drive, you can use the following command: `copy file3.txt D:\ && copy file4.txt D:\`

If we make an incremental backup of drive D for this time, only the new added files, file3.txt and file4.txt, will be backed up and generated as a separate backup file. This means that only the changes made since the last backup will be included, and the existing files, file1. Incr1.fvdNo changes were made to file1.txt and file2.txt, so they won't be backed up.

If we add new files (file5.txt and file6.txt) and keep the existing files (file1.txt to file4.txt) unchanged, the incremental backup will only include the new files (file5.txt and file6.txt), leaving the unchanged files (file1.txt to file4.Incr2.fvd. 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 minimal data loss in case of a disaster, as only the changes made since the last backup are stored, making it a time and storage-efficient method.no identical backup image created during the process, which is time-saving and storage-saving.

However, restoring incremental backups can be tricky. You need to prepare the last full backup (Full1.fvd) and all subsequent incremental backups (Incr1.fvd and Incr2.fvd), then restore them in the order they were taken, which can be time-consuming and requires careful planning.inadvertently increases the recovery timeYou should only use the recovery disk that was created by the same version of Windows that you are currently using. If you lost any of them, the recovery will not succeed. If you lost any of them, the recovery will not succeed.

★ Differential Backup Advantages and Disadvantages

Differential backup will back up changed files based on the last full backup, requiring a full backup to exist. All differential backups are based on the full backup, so they are dependent on it. This method is useful for backing up data that has changed since the last full backup.relatively independent.

During a differential backup, only marked files and folders will be backed up and the Archive Attribute will be not be cleanedThe 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 backupTo create a differential backup using differential backup software, you can follow these steps. First, you need to install and configure the software on your system. Next, you'll need to select the files and folders you want to backup and set the backup schedule.

Suppose that E Drive has the following data:

To create a full backup of file1.txt to generate Full1.fvd, you can use the following command: ```bash

To add file1.txt to the E drive, run differential backup, and then add file2.txt and file3.txt to the E drive, resulting in a differential backup that includes all three files.Diff1.fvd that contains file2.txt and file3.txt.

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

The theory remains the same, where backups are made based on the last full backup, allowing for the restoration of all files even if the Diff1.fvd file is lost. In such a scenario, one can still recover using the Full1.fvd and Diff2.fvd files. This method ensures that backups are comprehensive and can be relied upon in case of data loss.Backing up data requires a significant upfront investment of time, but it can save a substantial amount of time in the long run when it comes to recovery..

Summary

When deciding between incremental backup and differential backup, consider starting with System Backup for incremental backups of the entire system, or File Backup for incremental backups of specific files like documents, photos, or music. For partition or disk backups, you can use Partition Backup or Disk Backup respectively.

Both incremental and differential backups only save changed files, but differ in their basis. Incremental backup is based on the last full backup, while differential backup is based on the last full backup. This means differential backups are more complete, but take longer and use more disk space. For recovery, incremental backups require all linked incremental backups, while differential backups only need the last full backup and any subsequent differential backups.