From the very big to the very small – WD’s Purple and Red have it all

WD 18TB Purple and Red Pro HDDs and 1TB microSD card
WD 18TB Purple and Red Pro HDDs and 1TB microSD card

Western Digital is spreading 18TB bigness into WD Purple video surveillance and WD Red Pro NAS disk drives.

These are nine-platter conventionally recorded drives that use WD’s ePMR bias current technology to push capacity to 18TB.

18TB Purple 

The WD Purple 18TB drive has AI-oriented firmware, the company says. This will improve picture quality in video surveillance to help operators better detect events and people in the image stream.

Eric Spanneut, VP for WD’s client computing and smart video business, said: “AI is driving the need for more enhanced capabilities in drives to keep up with performance demands, especially as video resolution and the number of incoming streams increase.”

The WD Purple range extends from 1TB to 18TB. The low end, the 1TB – 6TB drives, have AllFrame 4K firmware and support 64 cameras. The 8TB-18TB models have different AllFrame AI firmware supporting 64 cameras and an additional 32 streams for deep learning analytics within the system to improve video streaming quality. This is for network video recorders (NVR) applications which encode and process data at the camera. How they use this is left unsaid. 

The previous WD Purple maximum disk capacity was 14TB. Drive spin speed varies with capacity. The 1TB – 4TB drives spin at 5400rpm, the 6TB one at 5700rpm, and the 8TB – 18TB ones at 7200rpm. They all have a 6Gbit/s SATA interface. Data caches are 512MB (14TB-18TB), 256MB (8TB – 112TB), and 64MB (1TB – 6TB). The sustained transfer rate varies with capacity, from 110MB/sec at 1TB to 272MB/sec at 18TB.

The 1TB to 6TB drives support a 24×7 180TB/year workload, 300,000 load/unload cycles, and carry one million hours MTBF rating. The 8TB to 18TB drives support a 24×7 360TB/year workload, 600,000 load/unload cycles and have a 1.5 million hours MTBF value.

In effect, there are two classes of Purple drive: low capacity, lower reliability, slower spinning models; and mid-to high capacity, faster spinning, higher reliability versions. 

18TB WD Red Pro

The 7,200rpm 18TB WD Red Pro drive essentially uses the same mechanical components, recording methods, and interface as its Purple sister.

But it has NAS-oriented firmware and has a 5-year warranty and 1 million hour MTBF rating. The WD Purple drive has a three year warranty, and MTBF rating of 1.5 million hours. So the NAS drive is warranted to last longer but is less reliable than the WD Purple 18TB. We presume this reflects a different vibration pattern in a NAS drive bay compared with a video recording system chassis.

The WD Red Pro’s maximum sustained data rates and cache sizes are basically the same as the WD Purple drives, varying with capacity, which runs from 2TB to 18TB in 2TB increments.

1TB microSD card

WD 1TB microSD card

WD today also released the WD 1TB microSD card. This will help capacity-bound video cameras take higher resolution images.

Until today the top WD Purple microSD card capacity was 512GB. The doubling comes from upgrading to 96-layer 3D NAND. The card supports up to 500 write cycles ad operates in a temperature range of -25C to 85C. Health monitoring software enables compatible cameras to estimate the card’s remaining life.

The 16TB and 18TB WD Red Pro and WD Purple drives are expected to ship in October. The 1TB WD Purple microSD card should ship in November.

WD also has the WD Blue HDD line for PC use, which tops out at 6TB. The idea of an 18TB drive for PCs has appeal but backup times could be horrendously long and there’s an awful lot of data to lose if the drive crashes. We may never see 18TB disk drives on the desktop because of these concerns.

WD announced its first 18TB disk drive, the Ultrastar DC HC550 for data centre use, a year ago. In July this year, it introduced the 18TB WD Gold brand HDD for enterprise storage systems and servers.

Seagate is shipping 18TB Exos data centre drives and expects to ship its 18TB IronWolf NAS drive this month.