Western Digital takes forever to RMA their hard drive under warranty. Had to buy a spare just to get my NAS back up and running before I lose everything (I only have a 1 drive fault tolerance RAID array). Too bad I only have 5 drive slots. 4 4TB WD Reds and an SSD for caching = 10TB usable space in this configuration. Actually this kinda pisses me off....I pay for 4TB drives and I get 3.64TB. For the 4 drives, that's a loss of 1.44TB.