What is a key feature of systems designed with N+1 redundancy?

A key feature of systems designed with N+1 redundancy is the inclusion of additional units that can take over in the event of a failure of one unit. This design approach ensures that there is always at least one backup component available to maintain system operations and reliability. For example, if a primary power supply unit fails, the additional unit (the +1) can seamlessly take over, preventing any interruption in service and maintaining the system's functionality.

This redundancy is crucial in critical applications where uptime is essential, such as data centers or healthcare facilities. The design ultimately enhances reliability and availability without necessitating a complete shutdown for maintenance or unexpected events. By having that additional capacity, systems can continue operating despite individual component failures, therefore upholding operational integrity.

In contrast, the other options do not accurately reflect the primary advantage of N+1 redundancy. A single UPS does not align with the redundancy concept, as it lacks backup capabilities, while claiming that such systems cannot undergo maintenance ignores the very purpose of redundancy, which is to enable maintenance without service disruption. Lastly, labeling these systems as less cost-effective overlooks the long-term benefits gained from reduced downtime and increased reliability, which can often outweigh initial costs.