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WD Ultrastar 18TB HDD DC HC550 7200RPM SATA 6Gb/s 3.5" Enterprise Hard Drive - WUH721818ALE6L4 (0F38459)

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Form Factor3.5"
Spindle Speed7.2K RPM
Warranty5 Years Manufacturer

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Western Digital Ultrastar DC HC550 18 TB SATA Hard Drives

Ultrastar DC HC550 (0F38459)

18TB Provides 29% more capacity than 14TB helium-filled drives

Ultra-low Watts per Terabyte (W/TB) 21% lower idle W/TB than 14TB Ultrastar helium-filled drives

Triple Stage Actuator and Two-Dimensional Magnetic Recording (TDMR) technology More accurate head positioning, especially in multi-drive environments, for better performance and data integrity

Rotational Vibration Safeguard (RVS) Maintains drive performance in high rotational vibration environments and multi-drive systems

Media Cache Plus architecture Better random write performance

512MB cache buffer Improves response time and data management

Dual Safe, RSA-signed firmware Retains previous firmware version for safe firmware updates, verified with an RSA signature

2.5M hours MTBF and 0.35% AFR Unsurpassed reliability rating for Capacity Enterprise HDD for fewer failures/less service needs

Tech Brief: Energy assisted magnetic recording

Manual: HC550 product documentation

Part Number Selector: HC550 part options


  • 18TB capacity in a standard 3.5-inch form factor
  • CMR technology works with all capacity enterprise applications & environments
  • Reliable, field-proven, 6th generation design
  • Industry’s first HDD with Energy-Assisted Magnetic Recording technology improves writability and therefore increases areal density
  • Industry’s first Triple Stage Actuator enhances head-positioning accuracy, delivering better performance and increased areal density
  • HelioSeal design delivers outstanding power efficiency
  • 2.5M hours (projected) MTBF rating & 5-year limited warranty
  • 512e SATA 6Gb/s
  • Legacy Pin 3 config – no power disable support
  • Base (SE), no encryption. Sanitize overwrite only


  • Cloud & Hyperscale storage
  • Massive scale-out (MSO), high-density data centers
  • Distributed File Systems
  • Bulk storage using object storage solutions like Ceph and OpenStack Swift
  • Primary and secondary storage for Apache Hadoop for Big Data Analytics
Type Enterprise HDD
Brand Western Digital
Series Ultrastar DC HC550
Model Number WUH721818ALE6L4
Part Number 0F38459
Form Factor 3.5"
Capacity 18TB
Interface SATA 6Gb/s
Spindle Speed 7.2K RPM
Tray Tray not included
Weight 1.7 lbs
Width 4 in
Height 1 in
Depth 5.8 in
Click to view WUH721818ALE6L4 datasheet
Condition - New : 5 Years Manufacturer Limited Period Warranty
Satisfaction Guarantee: Return for refund within 30 days of package reception date.
This item is covered by Return Policy
To initiate a return please fill out the Return Form
For frequently asked questions about warranties and returns please visit our FAQs
Our drives ship in 225lb per sq inch pressure-rated boxes, specifically tested for impact. Inside the box you’ll find suspension brackets, foam inserts, or air filled pockets that secure the drive in place and prevent any possible impact from movement in the shipping process. The drive itself is sealed in an anti-static bag that protects the drive from any electromagnetic interference.
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