Any Recommendment for a Drive to add to a MY Cloud Personal Cloud Storage?

I have just purchased a WD My Cloud (with lowest Capacity storage as I understand) and feel it a very good idea to attach a USB3 Backup Drive. There seem to be so many such devices with/without auto backup of files (WD or other Manufacturers) that I’m well confused.
Any experienced user’s advice would be gratefully received!

Hi there,

I would be good to specify if you are planning on using the external drive to backup the My Cloud unit or to use as an expansion of it, either way there shouldn’t be a problem connecting a USB 3.0 drive to the unit.