I have a Seagate ST32000542AS (2TB) hard disk and it was put in the left bay of DNS320, only 1 hard disk in NAS and Raid type is Standard. In Disk Management, I did Scan Disk and it was failed at about 66%. But when I did the S.M.A.R.T test, both Quick Test and Extended test got passed. So I am wondering, my disk is defected, or not? Should i immediately purchase another 2TB hard disk to make a RAID 1, or backup everything for this Seagate 2TB?