Incremental Vs. Differential Backup

In this age of information technology, data is a commodity. Every computer 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 doing it, which include a full, incremental, and differential backup.

Data storage, warehousing, recovery, and security are the emerging fields of information technology today and there are various software programs that can handle scheduled backups of your data. One of the main issues with the task is the time spent in doing it and the space required for it.

One needs a strategy that achieves economy of time and storage space to achieve the objective. There are two main strategies and they are known as incremental and differential backup.

The function of both types of backup is the same, but they differ in their approach.

Incremental backup achieves economy of time, by backing up information that has changed since the last full, incremental, or differential backup. It detects changes made in files and stores only the ones which have changed over time. Thus, it eliminates the redundancy in the process.

Differential backup saves all the files since the last full backup only. That means, every time it runs, some files may be stored repeatedly and the storage space required, will be a lot more than an incremental backup.

The advantage of an incremental backup lies in the time saved. Another advantage is that it takes lesser hard disk space, compared to a full backup. The advantage of going for a differential one is that it is faster than a full backup. The restore time for a differential backup is substantially lesser than other techniques.

Disadvantage of an incremental backup is that it is slow when it comes to restoring data, compared to a differential one. You need to have all the data from the last backup, as well as each incremental backup, for a successful restoration. Disadvantage of a differential back up is that it takes a lot of time to copy data and also uses up a lot of 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 adding more storage capacity.