What is an incremental backup?

What is an incremental backup?

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An incremental backup is a Recovery Manager (RMAN) backup in which only data blocks that were modified since the last incremental backup are backed up. Incremental backups are classified by levels. The baseline backup for an incremental backup is a level 0 incremental backup. A level 0 incremental backup, like a full backup, backs up all data blocks that have ever been used. However, a full backup cannot be used as the baseline backup for subsequent incremental backups.

Incremental backups at levels greater than 0 back up only data blocks modified since the last incremental backup. For example, a level 1 incremental backup will back up only those data blocks that have changed since the level 0 incremental backup. Furthermore, a level 2 incremental backup will back up only those data blocks that have changed since the level 1 incremental backup.

Incremental backups are quicker, and they occupy less space because they do not contain all data blocks. Incremental backups can be applied to the baseline backup, when required, in order to form a complete backup.

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