Your client has a NAS with ten 16 TB hard drives for a total capacity of 160 TB. He  reports that the storage array's average IOPS is insufficient to meet company needs. What might he use to replace the HDDs in order to maintain capacity while improving performance but with the minimum expense?

Because of their moving parts, HDDs have a natural speed disadvantage when compared to SSDs. The performance lag increases as hard disk storage grows larger. SSDs have no moving parts, hence they have substantially lower latency. Replacing old HDDs with several smaller drives or the same size SSDs would improve performance while increasing drive costs. When comparing drive performance, IOPS is the ideal measure to utilize.