36 Tb in 9 seconds is very fast, guess these are optimized plots? I am currently optimizing my plots on the main host (a Semi professional QNAP, NAS which has 43 Tb) and it currently takes 45 seconds (un-optimized plots) so nowhere near your speed. I don't think that hardware is rate limiting, it has a dual GB connection (trunked) and it reads to my workstation with 235 MB / s (close to the 2 Gbit it should have). The other drives are more of a problem, some reside in old DLINK NAS units which reads at best 15 MB / s. Those that are hooked up directly to internal SATA channels are fine (Seconds to read) but one computer has 12 drives hooked up. I don't know how the threading works in the miner (Blagos miner), but it seems that some are read very late. The CPU on that machine is a 2 core i3 so it does not handle threads well.
I did not realize this was a major problem, but I will try to optimize the hardware. Do you have any feeling if internet connection could be limiting (I am on a slow DSL (8 mbit) connection, which is stable but latencies are probably terrible.
I have not optimised the plots,but they are mostly plotted with a Stagger Size of 98304. Like most people it took a while to understand the best way to plot so some of them need replotting. My 36TB is all USB Drives mostly 4TB and a couple of 5TB typically split into 3 or 4 files / drive. I have another 6TB on a NAS drive but that takes 35 Seconds to read through.
I will try optimising but not sure that I will gain much, but did get some good gains by having dedicated channels for the drives and not connecting through a hub.
Rich