Backup type details are given below:
Full backup: It is a full copy of your entire data set. Although full backups arguably provide the best protection, most organizations only use them on a periodic basis because they are time consuming, and often require a large number of tapes or disk.
Incremental backup: Incremental backups were introduced as a way of decreasing the amount of time that it takes to do a backup. Incremental backups only backup the data that has changed since the previous backup.
For example, suppose that you created a full backup on Monday, and used incremental backups for the rest of the week. Tuesday's backup would only contain the data that has changed since Monday. Wednesday's backup would only contain the data that has changed since Tuesday.
The primary disadvantage to incremental backups is that they can be time-consuming to restore. Going back to my previous example, suppose that you wanted to restore the backup from Wednesday. To do so, you would have to first restore Monday's full backup. After that, you would have to restore Tuesday's tape, followed by Wednesday's. If any of the tapes happen to be missing or damaged, then you will not be able to perform the full restoration.
Differential backup: A differential backup is similar to an incremental backup in that it starts with a full backup, and subsequent backups only contain data that has changed. The difference is that while an incremental backup only includes the data that has changed since the previous backup, a differential backup contains all of the data that has changed since the last full backup.
Suppose for example that you wanted to create a full backup on Monday and differential backups for the rest of the week. Tuesday's backup would contain all of the data that has changed since Monday. It would therefore be identical to an incremental backup at this point. On Wednesday, however, the differential backup would backup any data that had changed since Monday.
The advantage that differential backups have over incremental is shorter restore times. Restoring a differential backup never requires more than two tape sets. Incremental backups on the other hand, may require a great number of tape sets. Of course the tradeoff is that as time progresses, a differential backup tape can grow to contain much more data than an incremental backup tape.
