I don't want to turn my drobo on its side and risk erasing it to get the serial number, therefore drobospace is still no use. I have to say the support on this product is pretty poor from the company. Got great help from this board though. Anyway, I bought three 500 gig HD's and needless to say am starting to fill them up. I was looking at getting a 1 TB drive but from looking at the drobo literature it will effectively waste the largest drive in its management of data. So.... am I stuck just buying another 500 gig drive? If I buy two 1 tb drives and replace one 500, how would I erase the 500 so I could sell?