Wednesday, March 2nd 2022
Western Digital Launches 20 TB NAS HDD with 64 GB iNAND
Although 20 TB hard drives aren't a new thing by now, Western Digital's latest drive for NAS appliances are doing things a bit differently by incorporating WD's OptiNAND technology. The WD Red Pro family is Western Digital's higher-end family of NAS drives and have a generally good reputation in the market. The drive is made up out of nine ePMR (energy-assisted perpendicular magnetic recording) platters, each coming in at 2.2 TB. As with the previously launched drives in the Red Pro family, we're looking at a 7,200 rpm drive with a SATA 6 Gbps interface. The internal transfer rate is said to reach up to 268 MB/s which makes it the second fastest drive in the series, just behind the 18 TB version.
What makes the 20 TB SKU unique in the Red Pro series though is the inclusion of 64 GB of WD's own iNAND flash. Western Digital's iNAND could be considered a DRAM-less SSD in a single chip package and in this case, it's used as a large chunk of cache for the hard drive. One other benefit of the OptiNAND technology according to WD is that up to 100 MB of data in the 512 MB DRAM write cache that the drive also has, can be flushed to the iNAND in case of an unexpected power cut to the drive. This could help save important data that is in transit during a worst case scenario and seems like a great addition to a hard drive that's targeting NAS applications. The WD Red Pro 20 TB is on sale now for US$499.99.
Source:
Western Digital
What makes the 20 TB SKU unique in the Red Pro series though is the inclusion of 64 GB of WD's own iNAND flash. Western Digital's iNAND could be considered a DRAM-less SSD in a single chip package and in this case, it's used as a large chunk of cache for the hard drive. One other benefit of the OptiNAND technology according to WD is that up to 100 MB of data in the 512 MB DRAM write cache that the drive also has, can be flushed to the iNAND in case of an unexpected power cut to the drive. This could help save important data that is in transit during a worst case scenario and seems like a great addition to a hard drive that's targeting NAS applications. The WD Red Pro 20 TB is on sale now for US$499.99.
40 Comments on Western Digital Launches 20 TB NAS HDD with 64 GB iNAND
documents.westerndigital.com/content/dam/doc-library/en_us/assets/public/western-digital/collateral/tech-brief/tech-brief-reimagining-hdds-with-optinand-technology.pdf
As for the rest, you're missing the point: they're saying that what makes a hybrid drive isn't what it is (an enclosure with a HDD+significant amount of flash), but what it does with those components. SSHDs typically use that flash as a R/W cache, with a focus on reads for frequently accessed files (system files etc.). StoreMI works in much the same way, though with even broader read caching. There is literally zero mention of such functionality concerning this drive, so it does seem that it works in a way that is quite different. I completely understand what you mean by saying that it's still a hybrid drive - it does still combine two storage technologies, after all - but barring that this WD blog post turns out to be just BS, there does seem to be a meaningful distinction here. If this entirely lacks read caching functionality, that is a very significant difference.
I last used a hybrid drive in my PS4 (seagate, still own it, its in a sdd box now), and it worked ok'ish, I remember tales of vesperia eventually hit SSD levels of performance about the 3rd or 4th time I played an area. No internal counters I think to measure erase cycles etc. on the nand.
Keep in mind that what WD means by workload: it's both writes and reads.
The drive is rated for 268MB/s so it only takes 311h to hit this workload limit. There are 8760 or 8784 hours in a year - WD uses the former. So unless my math is incorrect, it means that this HDD is only rated for 3,6% of a year. That's barely 13 days.
If you're fine with that for a drive having "Pro" in the name then be my guest.
Take into account specialized filesystems, often used in NAS or servers, like ZFS or Ceph which can have write amplification in order to keep the stored data secure. They also scrub all the data on regular intervals, so expect a lot of spurious reads.