Configuring and Backing Up Oracle Databases Using RMAN - OCP: Oracle Database 12c Administrator Certified Professional - page 153

The level-1 backup is the incremental backup that backs up changed blocks. There are
two different kinds of level-1 backups:
■ Differential incremental backup
■ Cumulative incremental backup
The differential incremental backup will back up all changed blocks since the last
level-1 backup. These images are typically smaller. The cumulative incremental backup is
one where the data backed up is the data that changed since the last level-0 full backup.
Thus it is a cumulative backup of all changed blocks since the last level-0 backup. This
makes for faster recoveries since you don't have to apply several incremental backups dur-
ing the database restore. Figure 3.5 provides a visual example of the differences between
these types of backups.

FiGURe 3.5 Differential vs. cumulative incremental backups

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Differential Backup

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Cumulative Backup