Design trade-offs for NAND flash-based SSDs

During the design phase of an SSD, the target application must be always taken into account. In fact, depending on the most important requirements, such as bandwidth, latency or reliability, architecture and cost of the drive might be totally different. Therefore, at the beginning of the development process, a thorough design space exploration is strongly recommended. In this chapter we describe the main actors of the drive architecture and we show how a dedicated CAD tool such as SSDExplorer can be used to optimize the SSD design, given a set of constraints. In particular, we consider 3 different cases: design for maximum bandwidth, design for minimum latency, and performance/reliability trade-off. Of course, in all cases SSD simulations are used to identify the right architecture to achieve the design target, while minimizing the resource request (e.g. number of Flash channels, number of NAND Flash memories, number of processor cores, etc…). For each case, this chapter includes design examples and corresponding simulation results. During the design phase of an SSD, the target application must be always taken into account. In fact, depending on the most important requirements, such as bandwidth, latency or reliability, architecture and cost of the drive might be totally different. Therefore, at the beginning of the development process, a thorough design space exploration is strongly recommended. In this chapter we describe the main actors of the drive architecture, when looking at bandwidth and latency.