Performance modeling and analysis of flash-based storage devices

Flash-based solid-state drives (SSDs) will become key components in future storage systems. An accurate performance model will not only help understand the state-of-the-art of SSDs, but also provide the research tools for exploring the design space of such storage systems. Although over the years many performance models were developed for hard drives, the architectural differences between two device families prevent these models from being effective for SSDs. The hard drive performance models cannot account for several unique characteristics of SSDs, e.g., low latency, slow update, and expensive block-level erase. In this paper, we utilize the black-box modeling approach to analyze and evaluate SSD performance, including latency, bandwidth, and throughput, as it requires minimal a priori information about the storage devices. We construct the black-box models, using both synthetic workloads and real-world traces, on three SSDs, as well as an SSD RAID. We find that, while the black-box approach may produce less desirable performance predictions for hard disks, a black-box SSD model with a comprehensive set of workload characteristics can produce accurate predictions for latency, bandwidth, and throughput with small errors.