SSD Performance and Cost
Explore the key differences in performance and cost between flash-based SSDs and traditional hard disk drives. Understand how SSDs deliver superior random I/O speeds, the reasons behind performance variations, and why cost remains a critical factor in storage system design. This lesson helps you evaluate when to use SSDs versus hard drives in persistent storage solutions and considers hybrid strategies for balancing cost and performance.
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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 particularly interested in how well the FTLs hide the performance issues of the raw chips.
The table below shows some performance data for three different SSDs and one top-of-the-line hard drive; the data was taken from a ...