Power management has become important in data centers. Since data center workloads are often dynamic, it is common practice to conserve energy by scaling resources up or down to match the workload. And since data centers often oversubscribe the power delivery infrastructure, operators can add power capping on top of these workload-proportional systems to adjust to available power. We find that this combination leaves performance on the table and provides only a limited power control range. Instead, we argue for power-adaptive systems that attempt to make the best use of the available power budget. To illustrate this approach, we built PASS, a power-adaptive storage system. PASS considers the interactions between different system components, including software and hardware, when making its power management decisions. For example, when under the same power constraint, PASS achieves 3–25× better throughput on filebench workloads than Intel's SPDK storage stack with Google Thunderbolt, a state of the art power capping system.

Power is becoming a scarce resource for data centers, raising the need for power adaptive system design---the ability to dynamically change power consumption---to match available power. Storage makes up an increasing fraction of total data center power consumption. As such, it holds great potential to contribute to data center power adaptivity.