Which metric defines how closely systems approach 100% data availability while maintaining performance?

Which metric defines how closely systems approach 100% data availability while maintaining performance?

• A. High availability (HA)
• B. Fault tolerance
• C. Disaster recovery
• D. Business continuity

Answer: (A)

The main idea here is availability: how reliably a system can deliver data and services to users without interruptions, while still performing well. High availability is built on design choices like redundancy, automatic failover, and load balancing so that even if part of the system fails, the overall service remains accessible and responsive. The key metric you care about is uptime or availability percentage—often framed as targets like 99.9%, 99.99%, or 99.999%—which quantify how close the system gets to 100% data availability in practice while still maintaining performance. The other terms describe strategies or plans rather than the measurement itself: fault tolerance is about eliminating downtime through redundancy and seamless switching, disaster recovery focuses on restoring service after a disruption, and business continuity covers maintaining critical operations during incidents.

The main idea here is availability: how reliably a system can deliver data and services to users without interruptions, while still performing well. High availability is built on design choices like redundancy, automatic failover, and load balancing so that even if part of the system fails, the overall service remains accessible and responsive. The key metric you care about is uptime or availability percentage—often framed as targets like 99.9%, 99.99%, or 99.999%—which quantify how close the system gets to 100% data availability in practice while still maintaining performance. The other terms describe strategies or plans rather than the measurement itself: fault tolerance is about eliminating downtime through redundancy and seamless switching, disaster recovery focuses on restoring service after a disruption, and business continuity covers maintaining critical operations during incidents.