The WD Re (WD4000FYYZ) comes in both 6Gb/s and 3Gb/s SATA and SAS flavors in a 7,200 RPM 3.5" form factor. The Re is geared for heavy workload environments in the datacenter, including RAID arrays, external storage arrays, data warehousing and data mining operations. The WD Re comes in a multitude of capacities, including 250GB, 500GB and the larger capacities, which weigh in from 1TB to 4TB's.
The RE fits in the middle of the WD datacenter product stack, with the Xe and Se bookends delivering different levels of service. The Xe provides the ultimate in performance with a SAS interface and 10,000 RPM's on tap. The Se is a 7,200 RPM HDD for less demanding workloads, delivering the incrementally lower performance via a SATA connection. The Re, or RAID Edition, HDD features higher resilience and performance than the Se in spite of the utilizing the same 7,200 RPM spindle speed.
HDD failures are a constant reality in the datacenter, and with some datacenters supporting tens of thousands of servers per location, and some housing far more, this constant stream of failures requires intense micromanagement. Workers spend countless man-hours replacing failed drives, and RAID rebuild periods strangle server performance and bring the threat of downtime. Once removed, failed drives are typically physically destroyed to protect customer or company data, adding yet another layer of expenditure to an already expensive process.
The Re brings a mix of different features that combine to deliver the higher speed and durability required in datacenter applications with heavy write workloads. The Re is designed to handle up to 550TB per year. The inclusion of a SAS interface also widens the spectrum of capabilities for the Re series. The SAS interface provides HA (High Availability) full duplex features, such as failover and multipath, and the robust SAS feature set.
The higher reliability of the Re, which features an MTBF of 1.2 million hours, helps to reduce the never-ending drive replacement cycle. While high-capacity drives from the competition also offer impressive MTBF specifications, the Re really distances itself from the competition with an industry leading 10E16 non-recoverable read errors per bits read. This is a 100x improvement over other drives with a 10E15 rating.
The Re also features a dual-core processor, with twice the processing power to boost performance. The SATA version features a healthy 64MB of cache, while the SAS version utilizes 32MB of cache. This combination combines to deliver up to 171 MB/s of sequential throughput for SATA, and 182 MB/s for the SAS version.
RAID-specific time-limited error recovery (TLER) prevents the drive from dropping in a RAID array due to an extended hard drive error-recovery. Dual actuator technology provides precise placement of the head over data tracks, while StableTrac secures both ends of the motor shaft to reduce vibration in multi-drive deployments. The WD Re series also has SED offerings with AES 256-bit encryption and Crypto Erase functionality for users with more stringent security demands. The SED drives support the T13 Sanitize command and the ATA Password support of Secure Erase Unit (SEU).
Reliability is key, and WD subjects their enterprise drives to at least five million hours of functional testing, and over 20 million hours of interoperability testing. Each individual drive also experiences an extended burn-in with thermal cycling to ensure reliability. The intense qualification and testing leads to a five-year warranty for the Re series of drives.