How to find out which files are loading the HDD?

Question

Nginx

Hello. There was a question. There is nginx distributing video on one disk, a heavy load, I want to move a file to an SDD for which there are so many requests. But how do you know which file has so many read requests?
atop on the desired disk shows the following
DSK | sdc | busy 91% | read 1155 | write 5 | KiB/r 122 | KiB/w 46 | MBr/s 13.81 | MBw/s 0.02 | avq 3.33 | avio 7.59 ms
How can I find out which file(s) have so many requests?

Answer 1

You can view open files (lsof command) and search among them.
Well, the analysis of nginx logs.

Answer 2

sudo iotop -a