A high-end network switch is experiencing intermittent power outages.

Hot-swappable components are specifically designed with redundancy in mind: multiple power supply units operate in an active-active or active-standby configuration so that if one unit fails, the remaining unit(s) automatically and immediately absorb the full load without requiring the system to be powered down, and without the need for the failed unit to be replaced before service continues. The defining benefit of hot-swappability is precisely this automatic, uninterrupted failover, which allows a technician to later physically remove and replace the failed unit while the switch continues running normally on the surviving power supply. Manual intervention in replacing the unit (A) will eventually be necessary to restore full redundancy, but it is not itself the 'most likely outcome' of the failure event; the immediate, automatic outcome is the failover, with physical replacement occurring afterward as a separate, non-urgent maintenance step. Performance degradation without shutdown (C) is a plausible characteristic of some failure scenarios but understates the specific redundancy mechanism at play here; a properly redundant, hot-swappable power configuration is designed to prevent even performance impact, not merely avoid a full outage. An immediate shutdown (D) is exactly the outcome redundant, hot-swappable power design exists to prevent. Automatic failover is correct.

Reference topic: Fault Tolerance Techniques - Redundant, Hot-Swappable Hardware Components.