A facilities engineer is provisioning power for a row of GPU racks. Each rack draws a sustained load near its budgeted maximum, and the requirement is that the loss of any single power feed or distribution unit must not bring a rack down. Which power design principle most directly meets this resilience requirement?
- ASizing a single power feed to exactly the rack's peak draw so that capacity is fully utilised and no headroom is wasted.
- BRelying on the cluster scheduler to migrate jobs off a rack within seconds whenever a power feed reports a fault.
- CLowering the per-GPU power cap until the whole rack fits within a fraction of one feed's rated capacity at all times.
- DProviding redundant power feeds and distribution in an N+1 configuration so the rack keeps running if any one feed or distribution unit fails. Correct
Why A is wrong: It is tempting because tight sizing looks efficient, but a single feed with no headroom offers no resilience and would take the rack down the moment that feed fails.
Why B is wrong: It is tempting because schedulers can drain nodes, but software migration cannot prevent the sudden power loss of an unfed rack, so it does not satisfy a feed-redundancy requirement.
Why C is wrong: It is tempting because capping power reduces draw, but it sacrifices performance and still leaves the rack dependent on a single feed, so it does not provide redundancy.
Why D is correct: This is correct because N+1 redundancy supplies at least one spare feed or distribution path beyond the rack's need, so the loss of a single component does not interrupt the supply.