Explore the Design Space of Solid State Drive by an Analytical Model

Solid State Drives (SSDs) based on NAND flash have been widely studied. Most related works focus on improving SSDs´ performance. Many novel techniques have been proposed to achieve this goal. In this paper, we don´t focus on any given technique, but explore several principles to design an SSD. Beforehand, we build an analytical model for SSDs by resorting to queueing theory. The model covers most characteristics of SSDs. So, it is able to emulate SSDs accurately. We analyze different workloads with the built model. Some interesting phenomena are revealed from the results. Based on these discoveries, we derive several advices to design an SSD. For example, we find that, decreasing write traffic not only extends SSD´s lifetime, but also reduces read latency. Therefore, we suggest that, it´s worthy to decrease write traffic at the cost of some computational overhead. Techniques such as compression and deduplication can be used to reduce write traffic, even though they bring in considerable overhead. Besides this example, there are other six principles as will be discussed.