Sleeping with One Eye Open: Fast, Sustainable Storage with Sandman

All-flash servers, while being widely popular for their high performance and large capacity, can incur significant energy consumption in modern storage systems. Through a motivational study, we discover that the culprit is the inefficiency in the software stack, and existing power-saving methods fail to deliver comparable performance, especially under workload bursts. Guided by the lessons learned, we propose Sandman, a scheduling framework that combines the fast resource scaling mechanism, resource monitoring, and I/O burst detection policies. Experiments show that Sandman reduces average power consumption by up to 39.38% and energy consumption by up to 33.36% while delivering performance comparable (within 5% in corner cases) to the best performance case (the busy-polling stack) in both benchmarks and field workloads.