CompTIA Server+ (SK0-005)Server Hardware Installation and ManagementMedium
A data center technician is troubleshooting a server experiencing intermittent power loss. Upon inspection, they notice that the server has two power supply units (PSUs), but only one power cable is connected to a power strip. Which of the following cabling best practices should the technician implement to improve power redundancy?
- AConnect one PSU to a UPS and the other to a wall outlet.
- BConnect each PSU to a separate PDU, with each PDU powered by a different UPS or power feed.
- CConnect both PSUs to the same power strip.
- DRemove one PSU to reduce power consumption and simplify cabling.
Show answer & explanationAnswer & explanation
Correct answer: B. Connect each PSU to a separate PDU, with each PDU powered by a different UPS or power feed.
To achieve true power redundancy, each redundant power supply unit (PSU) should be connected to an independent power path. This typically means connecting each PSU to a separate Power Distribution Unit (PDU), and those PDUs, in turn, should be fed by separate uninterruptible power supplies (UPSs) or distinct power feeds from the building infrastructure.
Why the other options are wrong
- A. Connecting one to a UPS and one to a wall outlet provides some redundancy but the wall outlet is unprotected.
- C. Connecting both PSUs to the same power strip eliminates redundancy if the strip fails.
- D. Removing a PSU eliminates redundancy altogether, making the server vulnerable to power supply failure.
Power Redundancy
The practice of using multiple, independent power sources and paths to ensure continuous operation of a server or system in case of a power component failure.
- Requires redundant PSUs in the server
- Each PSU must have its own independent power path
- Protects against failure of a single PDU, UPS, or power feed
Memory trick: Separate paths, separate power, always stay up, never fail an hour.