Definition - What does Failback mean?
Techopedia explains Failback
In failback, only the change data is sent to the original system. This makes it easier to effectively back up the system, because everything that was already contained in it is salvaged. There is no need to copy an entire drive or set of drives; failback just adds what was recorded by the backup facility during the duration of the crisis. To accommodate failback (and failover) developers must create a remote mirror and other critical setup for this kind of event handling.
Failover and failback capability is valuable for systems that need to comply with various regulations in an industry. For example, systems can use failover and failback as part of a Health Insurance Portability and Accountability Act (HIPAA) Disaster Recovery Plan for compliance with HIPAA, an American law that addresses the safety of patient health data.