Western Digital Ultrastar HC310 4TB 3.5" Enterprise HDD – 7200 RPM, SATA, 5-Year Warranty (HUS726T4TALE6L4)

You don't need six terabytes for this build. You need a drive that'll sit in a server or a RAID array and not give you a single error for five years. The Ultrastar HC310 4TB does exactly that. 7200 RPM, 256MB cache, SATA 6Gb/s. Rated for up to 550TB/year of sustained writes — the kind of workload that would kill a consumer drive in a year. Two million hours MTBF. Five-year warranty. If you're building an entry-level server, a VDI host, or a small storage node and you want the drive to be the last thing you think about, this is the one

• 4TB enterprise capacity with 7,200 RPM spindle and 256MB cache
• Rated for up to 550TB/year workload for sustained 24/7 server use
• 2,000,000-hour MTBF for long-term reliability
• SATA 6Gb/s interface; 3.5" form factor for standard server bays
• 5-year limited warranty included