Hi @Biju Mathew Thank you for posting your Question on Microsoft Q&A.
There is a correlation between the two: actual_read_time_ms = io_stall_read_ms - io_stall_queued_read_ms
The full explanation could come something like this :
You have 1000 IO that you want to perform in 1 second so you could get 1000 IOPS.
This means that every single IO will be in the queue and the 1000th will have to wait for a whole second; it is queued 999ms.
So, stalled is the time for read + time it was queued. And if you want to get the actual read time, you have to substract the previous two (the first equation).
Hope that helps
Regards,
Oury