A Hybrid Non-Volatile Cache Design for Solid-State Drives Using Comprehensive I/O Characterization

摘要

The emergence of new memory technologies provides us with opportunity to enhance the properties of existing memory architectures. One such technology is (PCM) which boasts superior scalability, power savings, non-volatility, and a performance competitive to (DRAM). In this paper, we propose a write buffer architecture for (SSDs) which attempts to exploit PCM as a DRAM alternative while alleviating its issues such as long write latency, high write energy, and finite endurance. To this end and based on thorough I/O characterization of desktop and enterprise applications, we propose a hybrid DRAM-PCM SSD cache design with an intelligent data movement scheme. This architecture manages to improve energy efficiency while enhancing performance and endurance. To study the design trade-offs between energy, performance, and endurance, we augmented Microsoft's DiskSim SSD model with a detailed hybrid cache using PCM and DRAM parameters from a rigorous survey of device prototypes. We study the design choices of implementing different PCM and DRAM arrays to achieve the best trade-off between energy and performance. The results display up to 77 percent power savings compared to a DRAM cache and up to percent reduction in request response time for a variety of workloads, while greatly improving disk endurance.