Western Digital is saying the sampling of its new 22TB CMR and 26TB SMR exhausting drives immediately at its What’s Subsequent Western Digital Occasion. As normal, the hyperscale cloud prospects will get first dibs on these drives. The important thing takeaway from immediately’s presentation is that Western Digital does not but really feel the necessity to carry heat-assisted magnetic recording (HAMR) into the image. In truth, WD is doubling down on energy-assisted PMR (ePMR) expertise and OptiNAND (launched first within the 20TB CMR drives). WD can also be persevering with to make use of the triple-stage actuator that it began transport within the first half of 2020 within the new drives. It goes with out saying that the brand new high-capacity drives are helium-filled (HelioSeal expertise). The principle change frequent to each drives is the shift to a 10-stack design.
The SMR drives are getting an added capability increase, because of WD’s new UltraSMR expertise. This includes adoption of a brand new superior error correction algorithm to go together with encoding of bigger blocks. This enables enchancment within the tracks-per-inch (TPI) metric, leading to 2.6TB per platter. The brand new Ultrastar DC HC670 makes use of ten platters to supply 26TB of host-managed SMR storage for cloud service suppliers.
ArmorCache Know-how
As a part of the bulletins, WD additionally offered further particulars on the caching characteristic enabled by OptiNAND – ArmorCache. Final yr’s announcement was fairly gentle when it comes to precise efficiency numbers, however the 20TB OptiNAND drives have been out available in the market for a couple of quarters now.
The UFS-based iNAND package deal helps the OptiNAND-based HDDs ship upwards of 80% enchancment in IOPS for low-queue depth large-sized random writes (10% – 20% enchancment for small-sized writes) in use-cases the place the write cache is disabled. Since non-OptiNAND HDDs can solely cache no matter may be flushed out to the serial flash throughout emergency power-off conditions, the bigger cache dimension afforded by the iNAND machine relaxes this limitation significantly. As mentioned within the OptiNAND announcement protection final yr, use-cases with write caching enabled profit from the EPO knowledge safety afforded by the iNAND machine. Enabling write caching typically requires hosts to ship out cache flush instructions to the HDDs. These instructions require the HDD to cease accepting new instructions till the completion of the flush, leading to lack of efficiency. The ArmorCache makes these flush instructions pointless, permitting the drive for use with full efficiency with no threat of knowledge loss as a consequence of EPO.
Concluding Remarks
The 22TB Ultrastar DC HC570 and 26TB Ultrastar DC HC670 are at present sampling to hyperscalers. Quantity cargo of the CMR drive to the channel is ready for the following quarter. The Ultrastar HC HC670 is a host-managed SMR drive, and can therefore ship solely to pick out prospects across the similar timeframe. Western Digital can be delivering variants of the CMR drive throughout its HDD portfolio – 22TB WD Purple Professional for surveillance NVRs, WD Crimson Professional for NAS techniques, and WD Gold for SMB and enterprise prospects in summer time.
The up to date capability factors – specifically, the leap within the SMR drive capability – delivers clear TCO advantages to WD’s cloud prospects. Crucially, WD believes it has sufficient belief in its ePMR setup to ship 30TB+ HDDs with out having to go the HAMR route. From a expertise perspective, it will make the upcoming roadmap / product bulletins from Seagate (HAMR deployment for publicly-available drives) and Toshiba (want for any expertise past FC-MAMR) attention-grabbing to look at.
