Incremental Backup Explained

Incremental backup is a feature, that analyzes your files, finds new and modified ones and uploads only them to your storage. To perform an incremental backup, you need, of course, to perform an initial full backup. Needless to say, that is one of the most efficient ways to perform your backup.
In this article, we will talk about incremental backup, its strengths and weaknesses, and about the implementation of incremental backup in CloudBerry Backup.

What is Incremental Backup

As we have already mentioned, that incremental backup will only upload new or modified files. Let's see how exactly it works.

Imagine that you have 5 files for backup and you are going to run weekly backups,
  • The 1st-week backup (initial full backup) will include all of them.
Then file1, file3 and file4 have been modified.
  • The 2nd-week backup will only copy these modified files: file1m, file3m, file4m.
Then file2 and file5 have been modified. They become file2m and file5m.
  • The 3rd-week backup will only copy file1, file3 and file5.
In the end - you will have a data set, that was completely changed for the new files. But each week the backup were uploading only the files, that changed during that exact week. That is how incremental backup basically works. If the file was not changed but added to the backup set somewhat after week 3 - it will appear on the week 4 as file6.

The Advantages of Incremental Backup

Needless to say, there are certain advantages in performing incremental backup compared to full backup. They are:

  • The speed of the whole backup operation. Incremental backup will upload only the changed and new files to the cloud or local storage. This is incomparably faster, then uploading the whole data set each time
  • Less storage capacity is needed. Nowadays, storage space means money. The less storage space you need - the less you will pay to the cloud storage provider. If you perform local backup - that means that you will spend less on your hard drives
  • Less bandwidth is consumed. When you perform backup, the last thing you want is your software to hang your internet connection for a long time

The Disadvantages of Incremental Backup

However, things are not so simple. Incremental backup is good, but not perfect. The main disadvantage of incremental backup is that it grows in size until the next full backup is done. In other words, incremental backup does not know if there were files, deleted from the very first full backup or any of the incrementals, but the pre-last one. To put it in a nutshell, last incremental compares itself with the pre-last.

For example, if you perform incremental backup for one year, without any additional full backups or retention rules, set to your files, you will have a yearly amount of data. All files, that were deleted since the full backup will remain in your storage. To avoid that from happening you should:

  • Perform the full backup from time to time. When you perform the full backup - you break the sequence of the previous incremental backups. In other words, you will backup only the files, that exist now on your device and the incremental backup will only do new files and changes since that last full backup
  • Set retention to your files. Retention policy allows you to choose, how long you keep your old files and how many versions of each file you keep. In case of incremental backup, it would be wise to set the retention to delete old files, after the given time, or files that were deleted from your device. The retention policy is a flexible tool. Learn how to use it properly.

Incremental Backup Software

CloudBerry Backup fully supports the concept of incremental backup, both locally and to the cloud, and enhances it with additional features. Our software performs incremental backup by default to ensure that there are no unnecessary copies of files and your storage space is used wisely.

Incremental Block Level Backup

However, an incremental backup may not be enough, if you have millions of files and they change a lot. In that case, you may want to look at an option, called block level backup. Block level backup analyzes files in-depth and backups only modified parts of the files. It's quite obvious, that the incremental block level backup is quite efficient.

This functionality is implemented in CloudBerry Backup and can be easily toggled from the UI of the software by going to the Backup Plan Wizard, until the step Advanced Settings.

Check out our blog article about block level backup if you want to know more about its architecture and implementation within CloudBerry Backup.

Point in Time Recovery from Incremental Backup

If you use incremental backup and have configured your backup plan well, then you will be able to recover your data, when needed, to the chosen point in time.

Let's say, that your computer was hit with ransomware. But you were not aware of this and the backup software has uploaded all files to the cloud, thus changing your previous files. In that unfortunate case, you can simply recover your files to the state of the previous week, when your files were not affected by ransomware.

Final Word

Incremental backup is quite a helpful feature. However, it should be carefully planned if you want it to be truly efficient. Plan your retention, plan the usage of block level incremental backup, plan the scheduling of your full backups. Planning is the key to the safety of your data and your storage budget.

Bonus Video

Also, check out our new video format - One Minute Drill. 
In this video, we will explain you the basics of incremental backup in one (roughly) minute.
If you liked this video - there will be much more to come. Let us know which topics will be most interesting for you.

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