Western Digital 22TB WD Gold, Red Pro, and Purple HDDs Hit Retail
Western Digital’s ‘What’s Next’ event back in May 2022 had seen the announcement of its 22TB platform based on ePMR and OptiNAND (with ArmorCache). At the event, WD indicated that the 22TB 10-platter drives would make its market appearance under different product categories – Ultrastar DC HC570 for data centers and enterprises, WD Gold for enterprises, SMEs, and SMBs, WD Red Pro for SMB and SME NAS systems, and WD Purple Pro for surveillance network video recorders.
Today, WD is announcing retail availability of these models along with technical details. All drives have a 3.5″ form-factor and sport a SATA 6 Gbps interface. The drives are equipped with a 512MB cache and have a 7200 rpm spindle speed. The acoustics rating for all of them are the same too – 20 dBA at idle and 32 dBA for the average seek.
Western Digital 2022 22TB Hard Drives – Metrics of Interest
WD Red Pro
WD Purple Pro
Rated Workload (TB/yr)
Max. Sustained Transfer Rate (MBps)
Rated Load / Unload Cycles
Unrecoverable Read Errors
1 in 10E15
1 in 10E13
1 in 10E15
Power (Idle / Active) (W)
5.7 / 9.3
3.4 / 6.8
5.6 / 6.9
Based on the above specifications, it is clear that Western Digital has taken the ePMR / OptiNAND / triple-stage actuator platform and tweaked the firmware suitably to cater to different market segments. The Red Pro CMR drive comes with NASware 3.0 firmware that includes features such as adjusting parameters based on the integrated multi-axis shock sensor, maintaining balance using the dual-plane balance control technology, and TLER (Time-Limited Error Recovery) configuration for compatibility with various NAS systems. As is customary for the Red Pro family, the new 22TB drives are recommended for usage in systems with up to 24 bays.
The WD Purple Pro drives meant for network video recordings has firmware tweaked for continuous sequential writes to multiple drive regions simultaneously. WD indicates the capability of the drive to handle up to 64 concurrent HD stream recordings at 3.25 Mbps, and up to 32 streams for machine learning / object detection tasks. Similar to NASware 3.0 in the Red Pro, the custom firmware has a specific moniker – AllFrame AI.
The WD Gold is the flagship in today’s retail launch announcement. It’s firmware is tweaked for the highest possible performance, without focusing on the active and idle power numbers. The ArmorCache feature is specifically turned on in the WD Gold 22TB model only.
The overall push with these high-capacity hard drives is one of TCO. The ability to reduce physical footprint of storage servers for the same capacity can result in significant savings in allied IT costs related to power, cooling, and rack space. Moving forward, WD can hopefully address the plateauing of access speeds compared to capacity (using dual-actuators or some other similar technology). This can make high-capacity HDDs attractive to home consumers / prosumers who may be rightly worried about long RAID rebuild times.
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