The 20TB Red Pro comes from WD’s range of NAS hard drives utilizing proprietary OptiNAND technology. This technology combines mechanical and flash storage technologies to deliver high capacity in a conventional magnetic recording (CMR) format that is significantly faster than competing single magnetic recording (SMR) drives. There is still a premium charge for this much space on a single device, but the performance is very predictable. No guarantees to mention, but if you need a lot of storage for continuous transfers, Red Pro can help.
WD uses 9 platters of 2.2 TB each in the 20 TB model, and additional capacity is made possible by storing necessary metadata to on-board flash. WD’s vision is to use Energy Assisted Perpendicular Recording (ePMR) to maintain the benefits of CMR technology while offering the unique benefits of OptiNAND. Many of the new features are only on the 22TB WD Gold for now, and while leveraging flash is a net gain for his WD, it adds complexity compared to Seagate’s solution.
specification
| product | WD Red Pro 20TB |
| capacity | 20TB |
| model # | WD201KFGX |
| Pricing | $329.99 |
| Cost per TB | $16.50 |
| interface | SATA 6Gb/s |
| form factor | 3.5 inch |
| technology | CMR (ePMR), OptiNAND |
| number of revolutions | 7200 |
| Sustained transfer speed | Up to 272MBps |
| cache | 512MB |
| Average read/write power | 6.9W |
| average noise | 32dBA |
| Workload rate limit | 300TB/year |
| MTBF | 1 million hours |
| guarantee | 5 years |
WD Red Pro comes in 2TB to 22TB in 2TB increments, but today we’ll be focusing specifically on the 20TB model. The current low price at the time of review is $329.99, or $16.50 per TB, which is not uncommon for the highest capacity drives and is on par with the $362.99 for the 22 TB IronWolf Pro. Currently cheaper than Seagate Exos X20 and IronWolf Pro 20TB. The drive runs at 7200 RPM and delivers sustained transfer rates of up to 272 MBps. This model has 512MB of cache, double that of the base model IronWolf Pro 20TB and Exos X20, but less cache at 12TB and below.
WD rates an average read/write power consumption of 6.9 W and produces an average of 32 A weighted decibels of sound. This is relatively quieter than the lower capacity one, but consumes more power. WD warrants the Red Pro lineup for 5 years at a workload rate of 300 TB per year. This means that 300 TB of data can be written to the drive per year with a mean time to failure of 1 million hours. That’s less than our competitors’ 1.2-2.5 million hours. Like the IronWolf Pro and Exos X20, the Red Pro uses CMR rather than slower single magnetic recording (SMR) technology.
The Seagate Skyhawk AI 20TB is intended for a different workload than other drives and costs more. However, the MTBF rating is a full 2.5 million hours and the workload rate limit is 550 TB per year. Included in the test for comparison purposes.
Software and accessories
WD offers downloads on its website, including the Western Digital Dashboard and the Acronis True Image for Western Digital application. The dashboard provides basic functionality such as providing drive information, monitoring SMART attributes, and updating firmware. OEM Acronis True Image allows you to back up your OS and other files, clone your drive, and more. Red Pro does not have the 3-year Rescue Data Recovery service included with IronWolf Pro.
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The Red Pro looks nothing unusual, but the label says it has NASware 3.0. Optimized for use in NAS systems and enclosures, this firmware technology essentially works to balance a variety of characteristics for the best combination of performance and reliability. This is basically marketing, but it’s true that hard drives should be designed for 24/7 environments, taking into account the noise and vibration of having multiple drives in a confined space. .
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The drive features a Broadcom main controller, spindle controller, and 4Gb or 512MB DDR4 for DRAM write cache. A controller system-on-chip (SoC) must be designed to work with flash for OptiNAND functionality. The cache is larger than the 256MB found in some competing drives, and he probably benefits from the cost savings realized by OptiNAND.
Onboard is also a 64 GB SanDisk labeled 64-layer BiCS3 NAND flash. This is actually an iNAND (Industrial NAND), designed for embedded environments and integrated as a Universal Flash Storage (UFS) Embedded Flash Drive (EFD). Such flash can operate in pSLC and TLC modes depending on the workload. Write workloads benefit from pSLC, while read workloads benefit more from TLC.
This implementation is not the same as a Solid State Hybrid Drive (SSHD) and flash is used primarily to improve performance and capacity by handling drive metadata. WD’s current approach to high-capacity drives is potentially cheaper, and OptiNAND enables some nice features like ArmorCache for emergency power-off (EPO) scenarios. However, other approaches used to gain additional capacity have different trade-offs, as omitting the use of flash is less complex.
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