I have been using my DNS-320 with only one 2TB drive installed for about 6 months. It is used as the backup for 3 laptops. I have just purchased a second 2TB drive and was looking to use it as a mirror of the first. Before installing the second 2TB drive, should I backup the first 2TB drive? I've read that if the a second drive is installed, the DNS-320 will format BOTH drives with of course, the loss of all data on the first drive which would defeat the object.