WD 6TB 3.5" Re 7200 RPM SATA III 128 MB Cache Bulk/OEM Enterprise Hard Drive (WD6001FSYZ) High capacity Near line drive - Massive capacities up to 6TB suit even the most demanding datacenter, enterprise server, or cloud storage needs. Designed for high-intensity applications - Designed to handle up to 550TB per year - the highest workload capability of any 3.5-inch hard drive - delivering both performance and reliability to any datacenter environment. Designed for durability and reliability - With up to 1.4 million hours MTBF, this high performance drive delivers the highest level of reliability for 24x7x365 operation in the most demanding storage environments. Designed for quality and reliability - Datacenter drives undergo at least 5 million hours of functional testing, and over 20 million hours of comprehensive Interoperability testing in an extensive array of server and storage systems. Multi-axis shock sensor - Automatically detects the subtlest shock events and compensates to protect the data. RAID-specific, time-limited error recovery (TLER) - Prevents drive fallout caused by the extended hard drive error-recovery processes common to desktop drives. Dynamic fly height technology - Each read-write head's fly height is adjusted in real time for optimum reliability. A head-positioning system with two actuators improves positional accuracy over the data track(s). The primary actuator provides coarse displacement, the secondary actuator fine tunes the head positioning to a higher degree of accuracy.