Façade: Virtual Storage Devices with Performance Guarantees

High-end storage systems, such as those in large data centers, must service multiple independent workloads. Workloads often require predictable quality of service, despite the fact that they have to compete with other rapidly-changing workloads for access to common storage resources. We present a novel approach to providing performance guarantees in this highly-volatile scenario, in an efficient and cost-effective way. Façade, a virtual store controller, sits between hosts and storage devices in the network, and throttles individual I/O requests from multiple clients so that devices do not saturate. We implemented a prototype, and evaluated it using real workloads on an enterprise storage system. We also instantiated it to the particular case of emulating commercial disk arrays. Our results show that Façade satisfies performance objectives while making efficient use of the storage resources—even in the presence of of failures and bursty workloads with stringent performance requirements.