Western Digital officially announced its 20 TB HDDs earlier in September. Leveraging the OptiNAND technology as well as iNAND UFS embedded flash drive (EFD) on the PCB, these drives are based on a 3D TLC UFS flash memory from either Micron, Samsung, or Hynix.
WD CEO David Goeckler stated in a conference call with investors and analysts that volume shipments of the 20 TB HDDs using OptiNAND technology will commence in November. These HDDs pack nine platters with a single-disk capacity of 2.2 TBs, and leverage ePMR (Energy Assisted Vertical Recording Technology). The drive heads use a more accurate three-stage drive technology, allowing a precise positioning of the read and write heads.
OptiNAND adds a number of advantages to these HDDs. Both RRO data and write operation metadata can be stored in iNAND flash memory, not only reducing the disk space occupation but also the number of hard disk read and write operations (IO number). The UFS flash memory can also store sector-level write operation data, which can optimize storage requirements and reduce ATI (adjacent track interference data) refresh times to improve performance. The SoC control chip of the hard disk is independently developed by Western Digital.
Western Digital’s 20 TB OptiNAND HDDs are suitable for cloud and enterprise servers, and it’s not clear whether they’ll be available to consumers anytime soon.