Western Digital has announced a “breakthrough in storage that works differently”, in the form of a new architecture that combines traditional dishes with solid state flash: OptiNAND.
Adding flash to traditional mechanical hard drives is not a new concept. Western Digital announced its first work on the concept back in 2011 after being marketed by competitor Seagate’s Momentus XT, a year earlier. In both cases, the solid state flash acted as a temporary buffer for the most accessible data – trying to mix the best of both storage worlds.
However, OptiNAND is located differently. Instead of just improving the throughput and access time of the user’s most researched data, an OptiNAND-enabled drive is claimed to offer increased total capacity, improved disk performance, and a fifty-fold increase in the amount of data retained if you accidentally pull the power in the middle. a write.
The heart of the system, in addition to the spinners themselves, is a Universal Flash Storage (UFS) standard Embedded Flash Drive (EFD) called iNAND, developed in Western Digital’s subsidiary SanDisk. Instead of acting as a simple cache, the iNAND disk handles metadata about writing positions and volumes – as part of an update system designed to avoid adjacent track interference, where a frequently written track will begin to affect data stored on the tracks around it.
“It used to be, not so many generations ago, that you could write 10,000 times before you had to update sectors on each page,” David Digital technician David Hall explained in an interview for the company’s blog. “And as we pushed the tracks closer and closer together, it went to 100, then 50, then 10, and now for some sectors it’s as low as six.”
Traditional update systems rely on tracking this metadata in DRAM, but accuracy is limited. Tracking the same metadata in more spacious iNAND, or what Western Western has claimed, improves accuracy – and allows engineers to increase the area density of the mechanical parts of the drive, and pack more storage space in the same number of barrels.
The first OptiNAND stations, sampling to “select customers” now, combine technology with energy-assisted, vertical magnetic recording (ePMR) to offer 20 TB storage on nine barrels – 2.2 TB per barrel, the company’s highest area density yet.
At the same time, OptiNAND is claimed to offer improved performance by reducing the number of track updates required, as well as the number of write-cache flushes. The latter is also linked to claims of improved reliability, with WD claiming that an OptiNAND station can retain “almost 50x more customer data” in the event of an unexpected shutdown.
“With our world-class HD and flash IP and development teams, we are able to continually push the boundaries of innovation to improve customers’ storage infrastructure,” said Siva Sivaram, President of Global Digital and Strategy at Western Digital.
“We have had an extraordinary journey for HDD innovation. We changed everything with HelioSeal in 2013; should first send energy-based HDDs in volume in 2019; and now we will lead again with OptiNAND technology. This architecture will underpin our Roadmap for Multi-generation HDD technology, as we expect an ePMR HDD with OptiNAND to reach 50 TB in the second half of the decade. “
Western Digital had not responded to a request for pricing and commercial availability of the 20TB OptiNAND drive at the time of publication. ®