Drobo with 3 x 1tb drives, first three bays filled. I have filled all of them, i have a 500gb drive knocking about but wont want to keep this in long nor would it last long. I want to add a fourth 1tb drive to replace the 500 gb when next possible is this okay? like im guessing drobo replaces smaller drives before larger. Also question of what if i take out a 1tb drive by mistake and put it back in? will it erase or know it was apart of drobo before?