Hi, Thanks for ideas.
I just kept adding external hard drives for various reasons...main storage, backup, mirror drive etc. Got into photography and then really needed additional storage. I originally went to 5tb Seagate drives but killed 2 of them..1 drop another died during an office move, so decided to go with smaller drives, so failure not as catastrophic.
I have since added external drive dock and added 2 4tb drives, one inside the case and 1 in the dock.
This seems to be working, but dock does lose connection to computer occasionally.
Thanks again
Dennis.