TSG Reliability Practice Exam

Which statement differentiates standby configurations and their impact on availability?

Hot standby is powered off until needed.

Warm standby provides continuous operation with no switch time.

Cold standby offers the fastest switch to operation.

Hot standby is active redundancy and provides the fastest switch to operation.

Standby configurations differ in whether the backup system is running and ready to take over. Availability is all about how quickly service can resume after a failure, i.e., the switch-over time.

In hot standby, the backup system is actively running and synchronized, providing active redundancy. Because it’s already operating, there’s no practical delay to switch over, so the downtime is minimized and availability is maximized.

Warm standby keeps the backup prepared but not fully active; it requires some steps to activate, so switch-over is fast but not instantaneous, leading to a small but nonzero downtime.

Cold standby keeps the backup powered off or unavailable until a failover occurs, so it must boot and configure before it can take over, resulting in the longest downtime among the options and the lowest availability.

Thus, the statement that hot standby is active redundancy and provides the fastest switch to operation best differentiates standby configurations and their impact on availability.