Distinguish failover from failback in a redundant system.

• A. Failover is returning to the primary system when healthy; failback is switching to standby after a failure.
• B. Failover is data replication; failback is data restoration.
• C. Failover is switching to a standby system after a failure; failback is returning to the primary system when it is healthy again.
• D. Failover is planned maintenance; failback is unplanned downtime.

Answer: (C)

In a redundant system, there are two roles: the primary that handles traffic and a standby that can take over. Failover is switching to the standby after the primary fails or becomes unavailable, so service keeps running without interruption. Failback is returning operations to the primary once it is repaired and healthy again, usually after confirming it’s synchronized with the standby and ready to take back the workload. This distinction matters because failover focuses on maintaining availability during a failure, while failback restores the original architecture once recovery is complete. The other descriptions mix up the timing or purpose—failover isn’t simply data replication, failback isn’t just data restoration, and failover isn’t about planned maintenance.