Spec: WD My Book Due 16Tb, it is set to raid 1 (mirroring); not connected with any other USB drives
My machine: Mac Mini 2012 Server
I brought the WD for about a week, and it never stop the “breathing” rhythm even my computer is asleep; the LED will only stay still when my system is booting up (it means for about 5 seconds). All the rest of the time it is non-stop (which indicates there is data going in and out, which i have not done anything on my computer.)
And I have excluded Time Machine from backing up this drive.