J Metz writes on the Cisco Data Center and Cloud Blog:
There are different ways to use Flash, of course, and different architectures abound in the marketplace — from fully “All Flash Arrays” (AFA), “Hybrid Arrays” (which are a combination of Flash and spinning disk), to more traditional systems that have simply replaced the spinning drives with Flash drives (without much change to the architecture).
Even through these architectures, though, Flash is still constrained by the very basic tenets of SCSI connectivity. While this type of connectivity works very well (and has a long and illustrious history), the characteristics of Flash memory allow for some capabilities that SCSI wasn’t built to do.
NVMe is going to be very important soon with the way flash memory is driving performance. J gives an excellent overview here.
Read more at: NVMe for Absolute Beginners