What is PSU redundancy?

• A. A single high-capacity power supply.
• B. A spare PSU capacity equal to one unit or at least one extra unit to maintain uptime during failure.
• C. A system that batteries power for load shedding.
• D. Backplane's role in distributing power.

Answer: (B)

Redundancy for power supplies means having extra PSUs available so the system stays up if one unit fails. The best description specifies spare PSU capacity equal to one unit or at least one additional unit to maintain uptime during a failure. This setup provides continuous power delivery, eliminates a single point of failure, and often supports hot-swapping, which is essential in data center environments.

Having a single high-capacity power supply offers no backup if it fails. Batteries used for load shedding focus on reducing immediate power draw rather than providing a redundant power path. The backplane’s role in distributing power concerns routing power within the system, not ensuring availability through redundant units.