From the Introduction:
The storage performance requirements of 3rd Platform computing workloads demand more than what traditional hard disk drive (HDD)-based architectures can cost effectively deliver. As a result, flash-based storage is rapidly penetrating the datacenter. Flash operates very differently in terms of read/write performance than traditional HDDs, and this has major implications for how testing should be performed on flash-based arrays.
There are several types of flash-based arrays where these considerations apply: all-flash arrays (AFAs), all-flash configurations of hybrid flash arrays (HFAs), and some more flash-optimized HFAs. Although early HFAs exhibited storage performance characteristics more similar to that of HDD-based arrays, these offerings are becoming increasingly flash optimized, narrowing the performance differences between them and AFAs. End users that are testing flash-based arrays for use in their production datacenters need to understand how flash-based arrays and flash-based testing is different.