R&D: zQoS, Unleashing Full Performance Capabilities of NVMe SSDs while Enforcing SLOs in Distributed Storage Systems

ACM Digital Library has published, in ICPP ’24: Proceedings of the 53rd International Conference on Parallel Processing, an article written by Liuying Ma, Zhenqing Liu, Jin Xiong, Yue Wu, Institute of Computing Technology, Chinese Academy of Sciences, China, Renhai Chen, Xi Peng, Ying Zhang, Gong Zhang, Huawei Technologies Co. Ltd., China , and Dejun Jiang, Institute of Computing Technology, Chinese Academy of Sciences, China.

Abstract: “Nowadays, data centers consolidate latency-critical (LC) tenants and best-effort (BE) tenants on the same cloud platform to increase resource utilization and reduce costs. In such a scenario, the underlying distributed storage systems are responsible for guaranteeing SLOs for LC tenants while maximizing bandwidth for BE tenants. As high-performance NVMe SSDs are widely deployed, how to make full use of their performance capabilities and guarantee SLOs has become an urgent problem. However, current methods restrict the performance capabilities of NVMe SSDs based on a conservative offline model, and also ignore runtime changes in tenant loads and device states, which definitely affect the performance capabilities.“

“In this paper, we present zQoS, an efficient technique that unleashes full performance capabilities of NVMe SSDs, and increases bandwidth of BE tenants while guaranteeing SLOs of LC tenants. First, zQoS builds a more accurate offline performance model for NVMe SSDs to accurately reflect their performance characteristics. Second, a fine-grained online adjustment mechanism is proposed to dynamically adjust the performance capabilities of NVMe SSDs at runtime. Finally, to cope with abrupt load changes, an adaptive per-tenant adjustment method is designed to guarantee SLOs and increase utilization. We evaluate zQoS in a wide variety of mixed workload scenarios. Results show that zQoS significantly outperforms the state-of-the-art approaches. It achieves up to a 17x increase in BE tenant bandwidth without violating LC tenant SLOs.“