Starting with Oracle 12c, Oracle does not require the database to be quiesced (placed in hot-backup mode) to create a recoverable state. This capability is called Storage Snapshot Optimization. To use it, Oracle requires that a snapshot of a live database is created using a consistent storage snapshot, and that the snapshot time is known. During media recovery, the snapshot creation time is provided, and the recovery process will ensure that the archive logs are applied from a database checkpoint prior to the snapshot and until the datafiles regained consistency (no longer ‘fuzzy’), with the ability to continue and apply additional archive or redo logs as available.

This feature is very important because it means that you can take consistent snapshots in short intervals and each such snapshot is a valid database backup that can be used to recover the database if needed. It also means that Oracle hot-backup mode is not necessary, allowing us to be more aggressive in our backup (or snapshot) strategy for more granular database protection.