CompTIA Server+ (SK0-005)Server Hardware Installation and ManagementMedium
A server contains two redundant hot-swappable power supplies. Which of the following cabling configurations BEST protects the server against a single PDU failure?
- AConnect both power supplies to the same PDU on adjacent outlets
- BConnect each power supply to a separate PDU fed from independent circuits
- CConnect both power supplies to a single UPS using a shared power strip
- DConnect one power supply to a PDU and leave the second supply uncabled as a spare
Show answer & explanationAnswer & explanation
Correct answer: B. Connect each power supply to a separate PDU fed from independent circuits
To achieve true power redundancy, each power supply should be plugged into a different PDU, ideally fed from separate circuits or even separate utility feeds, so that the failure of one PDU or circuit does not take down the server.
Why the other options are wrong
- A. A single PDU failure would remove power from both supplies simultaneously.
- C. A shared strip and single UPS still represent a single point of failure.
- D. Leaving a redundant supply uncabled defeats the purpose of redundant power.
Redundant Power Distribution
Redundant power supplies should be connected to separate PDUs/circuits so a single power path failure does not cause a server outage.
- Dual PSU servers need diverse power sources for true redundancy
- PDUs (Power Distribution Units) can be A/B fed from different circuits
- Best practice: each PSU cord goes to a different PDU/UPS
Memory trick: Two power supplies, two different plugs — never share a single point of failure.