Review on HGST Ultrastar 7K4000 4TB 64MB Cache 7200RPM SATA 6.0Gb/s 3.5inch Internal Hard Drive - Ideal Storage Solution for NAS, Desktop PC/Mac, Surveillance, CCTV DVR - 5 Year Warranty (Renewed) by Eric Stewart

I bought 7 of these drives for my home server and expect to use them in the data center for some time. I tested them all in the Seagate SeaTools tester and the SMART report for each drive shows 0 hours of use and 0 TB write access. Either they were never used or they somehow erased all SMART data on the drives. Anyway, they all passed the driving test, the noise is audible but normal and there are no signs of physical wear and tear. They're included with my server now, but with a 5-year warranty on all, I don't have to worry about premature failures. Update: I ran into some issues with 5 drives on my TrueNAS 12.0-U5.1 server. 2 of them failed to format initially, 2 of them randomly shut down and another started failing SMART tests and showing checksum errors. The seller is very cooperative in replacing these drives, but it's a little annoying when it happens in the beginning.