How can I see/hear if my Wd my book is in Hibernation

I attached my 6tb My Book to my Nas (synology). I set up the hibernation on the Nas and on the Drive itself. How can I now see if the drive is in sleep mode? I can still hear a sound its hard to describe, its like a really silent fan, i will try to record it, but there are no hdd like sounds anymore (clicking). The my book doesnt have a led.
It also seems that it shuts down and then wakes up like imediately after that.

Thx guys