Data replication and snapshots are the key to disaster recovery and making your system reliable. Replication creates a copy of the primary data site on the secondary site, and in the event of primary system failure, the system can fail over to the secondary system and keep working reliably. This data could be your file data stored in a NAS drive, database snapshot, or machine image snapshot. Sites could be two geo-separated on-premises systems, two separate devices on the same premises, or a physically separated public cloud.
Data replication is not only helpful for disaster recovery, but it can speed up an organization's agility by quickly creating a new environment for testing and development. Data replication can be synchronous or asynchronous.