there is quite a bit of partial and somewhat obviously misconstrued ("buy my great sh!t") information out there about how to combine RAM, NVMe, SSD, SATA and RAID in order to optimize IO performance. You also hear about ZFS licensing and performance issues in Linux.
I'd wish I could find a book explaining IO performance right from the physics of it to the OS system level algorithms to optimize transfer rates in a "nullius in verba", "and-here-is-how-you-test-it" kind of way. Any comprehensive readings regarding such matters you would share? lbrtchx