Wednesday, December 7th 2022
Seagate Mechanical HDD with U.2 NVMe Interface Pictured, Signals the Decline of SAS 12G
Here's one of the first pictures of a mechanical HDD with NVMe interface. Seagate is apparently in production of an Exos-series Enterprise HDD featuring U.2 NVMe interface where one would expect SAS 12 Gbps. We seriously doubt if the HDD is fast enough to take advantage of U.2 NVMe (at least 32 Gbps per direction), but the move to NVMe probably has to do with the decline of older interface standards such as SAS 12 Gbps and SATA 6 Gbps in the enterprise space for cold-storage, and that future generations of rackmount DAS and NAS enclosures could increasingly feature U.2 backplanes, phasing out SAS and SATA. This is like when optical drives switched over to SATA despite not needing the bandwidth SATA had to offer (optical discs barely move a few dozen MB/s, for which even ATA33 IDE was sufficient). We don't know how the Seagate Exos drive handles NVMe internally—whether there is a new native NVMe controller, or whether this is really just a SAS 12 Gbps drive with a PCIe-to-SAS bridge chip.
Source:
Harukaze5719 (Twitter)
32 Comments on Seagate Mechanical HDD with U.2 NVMe Interface Pictured, Signals the Decline of SAS 12G
By converting hdd to native NVME we can get rid the need of additional SATA/SAS controllers. You do not need a SATA/SAS controller on the CPU/Mobo/Chipset, freeing up PCIE lanes so that you are free to utilize those lanes however you like, increasing flexibility. You free up space and die area required to have those controllers on your system so that you can make your system more compact or utilize that extra space for other more useful things in your system.
You are not forced to buy a chipset/cpu that has lanes taken up by the sata/sas controller, and in the future when you dont need those sata/sas anymore you don't need to switch your system/motherboard just to get your lanes back.
You do not need an addon pcie SATA/SAS card, saving on space and on cooling, and can therefore utilize those free pcie slots for other things.
It is possible we save on latency and power consumption especially if they made the NVME implementation native. We only need a single controller to communicate between the CPU/Chipset and the HDD. Saving power and time (by reduced latency) helps us go green as well, since the theme is now saving the planet. (Instead of CPU->Chipset->SATA Controller->HDD Controller ->HDD Platters, we get CPU->HDD Controller->HDD Platters)
(im not making fun of trying to save our planet, im making fun of ppl and companies that need a "theme" to sell more environmentally friendly products, and also the same theme is needed for consumers to be convinced to buy and use them)
edit: clarified some stuff and added pic of amd x670 diagram as example. credits to AMD and Anandtech.
wait what. This is a spinner!!!
:(
Nowadays you have HDDs that can push almost Sata II speed and 2TB SSDs are under $200.
HDDs in server racks will run on relatively slow interfaces like PCIe 2.0 x4 or x2 or even x1, so an interface card like PCIe 4.0 x8 can feed tens of them.
blog.seagate.com/enterprises/seagate-unveils-worlds-first-native-nvme-hdd-demo-at-ocp/
This doesnt signal the end of SAS this drive might just be to allow more drives in a system where SAS fully populated but u.2 spare.
What I suspect is that this is a trasitiionary product before EDSFF (E1S/L, E2, E3) formats take over and they need to adapt to those standards. Where as currently trying to get a E3 equipped server etc isnt that easy using the U2 interface would be a great way to test controllers on 12v vs 3.3 that normal contollers have been using for years.
Quote from gamers nexus, one of the few in the tech media who at least looked into U.2 vs M.2.Unless seagate say otherwise my opinion is this product is still to allow flexibility in a server might be out of SAS ports, but have U.2 ports available so thus allowing adding of more drives.
Crap. My first IBM XT with a "20MB" harddrive and the size of two 5.25inch floppy drives. Drives that could take a far more beating then todays drives that seem to fall out random whenever it wants.
Make a NAS/1U rack with NVME connectors, special mech drives still fit - tada, big sales
E3 is designed to replace 2.5 inch but basically is taking the current 7mm 2.5inch drives and making that the LARGEST size.
Actually a good document describing the new sizing format:
www.anandtech.com/show/16248/edsff-form-factor-updates
In theory the EDSFF formats can also have >4x PCI-E connections per drive so either inbuilt "RAID" or controllers with far more bandwidth is capable. I suspect this is more for high end database/ML servers where data throughput is Key.
Hybrids were good for using as an OS drive because they would cache the ~15gb worth of Windows stuff (or rather, the most accessed files in there) plus frequently used programs and files, but they aren't going to make the difference in photo backupsHave you heard about Intel Smart Response Technology? It lets you make a (64 gb max) SSD cache for your hdd. the remaining ssd space can be partitioned normally. AMD platforms have a similar tool. I guess it would help if you didn't want to meddle with two drives with different speeds and capacities.