Summary: I ordered two of these with the intent of using one as a primary and the second as a backup. I also ordered 16 Hitachi 2TB HD's from another vendor. Both units presented with hardware issues. The first would occasionally not recognize the 8th HD (it would indicate a drive wasn't plugged in when in fact one was). The second unit had issues recognizing the 2nd and then 3rd drive bay (it stated the disks were invalid.) The HD's all verified independently in another system.