CompTIA Server+ (SK0-005)Server Hardware Installation and ManagementHard
A server rack is being deployed in a new data center. The rack will house several high-performance servers, each with redundant power supplies. The data center manager wants to ensure that a single point of failure in the electrical distribution system does not bring down the entire rack. Which of the following power distribution configurations should be implemented for the rack?
- ASingle PDU connected to a single UPS.
- BDual PDUs connected to a single UPS, fed by a single circuit.
- CDual PDUs, each connected to a separate UPS, fed by separate circuits.
- DSingle PDU connected to two redundant UPS units.
Show answer & explanationAnswer & explanation
Correct answer: C. Dual PDUs, each connected to a separate UPS, fed by separate circuits.
To eliminate a single point of failure and ensure maximum uptime, each server's redundant power supply should be connected to a separate PDU, and these PDUs should, in turn, be connected to separate UPS units, which are then fed by independent electrical circuits.
Why the other options are wrong
- A. A single PDU and single UPS represent multiple single points of failure.
- B. A single UPS and single circuit are single points of failure, negating the benefit of dual PDUs.
- D. A single PDU is still a single point of failure for the entire rack, even with redundant UPS units.
Redundant Power Distribution
A server power architecture designed to eliminate single points of failure in the electrical supply chain, typically involving dual power supplies in servers, dual PDUs, dual UPS units, and sometimes dual electrical circuits.
- N+1 or N+N redundancy at every stage (server PSUs, PDUs, UPS, circuits).
- Prevents downtime from component failure or planned maintenance.
- Requires careful planning and cabling to ensure true separation.
Memory trick: Redundant Power is 'Double Everything' from the wall to the server.