Start with One Drive

If I buy this unit with no drives and add a 4TB drive to start, what happens when I add another 4TB drive? Will I lose the data on the first 4TB drive? Is this even a smart thing to do?

Thank you

It will just strip the data on the one drive to two. Personally I just ended up buying a 16tb setup because a rep gave me a 20% coupon. Plus if you have a school email you get a discount. Both ways ended up being cheaper than doing 1 drive at a time. Plus depending on the configuration you have it could be hazardous for your data if the 1 drive were to fail before drive two backed it up