Incremental Vs. Differential Backup

Data is a commodity in this age of information technology. Every computer today has important personal data on its hard drive in the form of digital camera pictures, documents, audio/video files and software. This data is vulnerable to software crashes and virus attacks that can render it useless. That is why, to protect this digital information, it's necessary that one backs it up periodically. There are three ways of backing up information, which are a full, incremental and differential backup. This article presents an incremental vs. differential backup comparison for your perusal. Reading through may help you decide which kind of backup to opt for.

Data storage, data warehousing, data recovery and data security are the emerging fields of information technology today and there are various software programs available that can handle scheduled backups of your data, for you. One of the main issues with storing or backing up data is the time spent in doing it and the space required for it. One needs a data backup strategy that achieves economy of time and storage space, while still achieving its objective. There are two main strategies and they are called incremental and differential backup.

Difference Between Incremental and Differential Backup

The function of both incremental and differential backup is the same but they differ in approach. One realizes that time and hard disk space are important commodities in his or her life! That is why a backup strategy that saves time and storage space is what you want.

Difference in Functionality
Let us first identify the fundamental functional difference between incremental and differential backup. Incremental backup achieves economy of time, by backing up information that has changed since the last full back up, incremental back up or differential back up. It detects changes made in files and stores only the files which have changed over time. Thus, it eliminates the redundancy in data backup too. During every new incremental backup, only the data that has changed since the last incremental back up is saved.

There is a very subtle difference between the functionality of differential back up and incremental back up. While the incremental backup stores changed files since the previous incremental back up, differential backup saves all the files since the last full back up only. That means, every time a differential back up process runs, some files may be stored repeatedly and the storage space required, will be a lot higher than an incremental backup.

Advantages of Each
The advantages of an incremental backup is that it takes a lot less time compared to a full backup. Another advantage is that it takes lesser hard disk space, compared to a full back up. The advantage of going for a differential back up is that it is faster than a full back up too. The restore time from a differential backup is substantially lesser than an incremental or full back up.

Disadvantages of Each
Disadvantage of an incremental backup is that it is very slow when it comes to restoring data, compared to a differential backup. You need to have all the data from the last back up as well as each incremental back up for the restoration to be successful. Disadvantage of a differential back up is, that it takes a lot of time to copy data. It also uses up a lot of storage space.

Ultimately, to back up data, you create more data and you need more storage space! Data only proliferates over time. There is no way of getting around that problem other than enhancing storage capacity!