SSD Performance and Cost

Before closing, let’s examine the performance and cost of modern SSDs, to better understand how they will likely be used in persistent storage systems. In both cases, we’ll compare to classic hard-disk drives (HDDs), and highlight the biggest differences between the two.

Performance

Unlike hard disk drives, flash-based SSDs have no mechanical components, and in fact are in many ways more similar to DRAM, in that they are “random access” devices. The biggest difference in performance, as compared to disk drives, is realized when performing random reads and writes. While a typical disk drive can only perform a few hundred random I/Os per second, SSDs can do much better. Here, we use some data from modern SSDs to see just how much better SSDs perform; we’re ...