Two-Level Storage QoS to Manage Performance for Multiple Tenants with Multiple Workloads

With more applications moving to cloud, scalable storage systems, composed of a cluster of storage servers and gateways, are deployed as the back-end infrastructure to accommodate high-volume data. In such an environment, it is a challenge to provide predictable and controllable storage performance for multitenanted users with multiple applications, due to performance violation from misbehaving applications. In this paper, we propose a two-level QoS controller over scalable storage system. On the higher level, I/O throughput rented by each tenant is guaranteed and strictly limited by a CAP value. On the lower level, this rented service can be on-demand served among multiple applications under the same tenant. Thus our distributed controller not only shields performance violation from "noisy" tenants but also allows tenants to fully utilizing the rented I/O throughput. Furthermore, the QoS controller is implemented in an efficient manner, by reusing the communication channels among gateways and storage servers and piggybacking control signals on data communications. The experimental results have shown that the two-level QoS controller can guarantee I/O throughput at tenant level by controlling the CAP value while accelerating applications by on-demand serving at a very little computation cost.