I'm writing this review as I attempt to rebuild one of these arrays with new disks. My company bought 3 of them to use as backup for our file server, and two of them have failed. We also have the smaller non-RAID 300GB versions for every desktop and laptop in our company (about 16) and none have had any problems. So I would stay far away from this one because it seems very failure prone. If the controller successfully lets me use replacement drives I'll post back here.Though even if it does, I wouldn't recommend this drive because the enclosure is not meant to be opened by an end user, and why on earth would you want RAID if you can't swap out a drive?