CompTIA Server+ (SK0-005)Server Hardware Installation and ManagementHard
A server rack is being designed to house critical infrastructure where even a momentary power disruption could cause significant data loss or system downtime. The design mandates that power to each server must be continuously available, even during a failure of a single power source or a single power supply unit (PSU) within a server. Which power infrastructure component is essential to meet this requirement for the entire rack?
- AIndividual surge protectors for each server's power supply.
- BDual, redundant Power Distribution Units (PDUs) connected to independent power feeds.
- CA single, high-capacity Power Distribution Unit (PDU).
- DA single Uninterruptible Power Supply (UPS) with sufficient runtime.
Show answer & explanationAnswer & explanation
Correct answer: B. Dual, redundant Power Distribution Units (PDUs) connected to independent power feeds.
Dual, redundant PDUs connected to independent power feeds ensure that if one power feed or one PDU fails, the servers (assuming they have redundant PSUs) can seamlessly draw power from the other. This eliminates single points of failure in the power path to the rack.
Why the other options are wrong
- A. Surge protectors only mitigate voltage spikes and do not provide continuous power during outages or protect against PDU or power feed failures.
- C. A single PDU, even high-capacity, represents a single point of failure; its failure would disrupt power to the entire rack.
- D. A single UPS provides battery backup but if the UPS itself fails, or the PDU connected to it fails, power to the rack would be lost. Redundancy at the PDU level is also needed.
Redundant Power Distribution Units (PDUs)
Two or more PDUs in a rack, each connected to an independent power feed, designed to provide continuous power to servers with redundant power supplies. This setup eliminates a single point of failure in the power distribution path.
- Requires servers with redundant PSUs.
- Each PDU connects to a separate power circuit/feed.
- Ensures power continuity if one PDU or feed fails.
- Key component of a highly available power infrastructure.
Memory trick: Redundant PDUs: Power Done Right, Double the Might.