The WD Xe is designed for mainstream server and storage applications. The Xe comes in capacities of 300, 450, 600, and 900 GB in a 2.5-inch form factor. The Xe spins at 10,000 RPM, has 32MB of cache, and features an average latency of 3.6ms. The Xe actually has a dual-core processor to help deliver top performance under the most demanding workloads, and it sports a sustained sequential data rate up to 204 MB/s.
WD provides several solutions for the datacenter, including the WD Re for the most demanding durability, and the WD Se for NAS and scale-out infrastructures. The WD Red fills the role of a drive for smaller deployments that typically service SOHO and SMB environments.
The Xe is the fastest of the WD drives; they currently do not offer a 15k option. The WD Xe actually has up to 67 percent lower power consumption compared to some 15,000 RPM drives, and WD feels the TCO savings are well worth the investment in their mainstream performance hard drive. WD focuses on power conservation, and the Xe draws under 8 watts during operation and 5.2 watts while idle.
The WD Xe has a host of features that enhance performance and reliability, including a full-duplex dual-port 6Gb/s SAS connection. This connection eliminates single point of failure to service HA (High Availability) environments. RAID-specific TLER (Time-Limited Error Recovery) helps protect data during extended hard-drive error recovery processes.
Reliability is always a concern in any environment, and the Xe features WD's StableTrac technology. This secures the motor shaft at both ends to combat vibration, stabilizing the platter for accurate tracking during read and write operations. Reducing vibration is important, but a multi-axis shock sensor that automatically detects and compensates for 'shock events' handles the inevitable vibration induced from multi-drive deployments. These features work in concert with the NoTouch ramp load technology that ensures the recording head never touches the disk's spinning platters. This protects the recording head and media from undue wear and protects the drive during shipment.
This multi-layered approach is topped off with RAFF (Rotary Acceleration Feed Forward) technology to optimize operation and performance in vibration prone environments, which applies to just about every server rack. There are actually two actuators to control the Xe's head movement. One provides coarse displacement using standard electromagnetic actuators, and the secondary actuator uses piezoelectric motion to fine-tune head travel. The head's fly height is adjusted in real-time for optimum performance. The culmination of these enhancements is a robust 2,000,000-hour MTBF.
WD also goes to extreme lengths to test their drives for reliability. Datacenter drives are subjected to over 5 million hours of functional testing, and over 20 million hours of interoperability testing using a vast number of server and storage systems. The drives are also tested during extended thermal burn-in and cycling. WD feels quite confident in their testing program and guarantees the life of the drive with an industry standard five-year warranty.