Thursday, June 3rd 2021

NVM Express Announces NVMe 2.0 Specification

NVM Express, Inc. today announced the release of the NVM Express (NVMe ) 2.0 family of specifications. The restructured NVMe 2.0 specifications allow for faster and simpler development of NVMe solutions to support the increasingly diverse NVMe device environment, now including Hard Disk Drives (HDDs). The extensibility of the specifications encourages the development of independent command sets like Zoned Namespaces (ZNS) and Key Value (KV) while enabling support for the various underlying transport protocols common to NVMe and NVMe over Fabrics (NVMe-oF ) technologies.

"NVMe technology is the leading interface for SSDs, with overall worldwide enterprise SSD capacity expected to grow at a 43% compound annual growth rate into 2024," said Jeff Janukowicz, research vice president, IDC. "NVMe architecture is designed for future SSD development and form factors, as we enter a new era in hyperscale and enterprise computing that drives digital transformation."
"We have rearchitected the NVMe 2.0 library of specifications to meet the evolving demands of the future of storage," said Amber Huffman, NVM Express president. "NVMe technology has unified client, cloud and enterprise storage around a common command set and architecture. Our Technical Work Group has worked diligently to optimize the features of the NVMe 2.0 specifications for diverse market segments, allowing for emerging use cases and opening new NVMe device types."

NVMe 2.0 Specifications: New Layout Will Propel Industry Development and Momentum

The NVMe 2.0 library of specifications consist of multiple documents, including the NVMe Base specification, Command Set specifications (NVM Command Set specification, ZNS Command Set specification, KV Command Set specification), Transport specifications (PCIe Transport specification, Fibre Channel Transport specification, RDMA Transport specification and TCP Transport specification) and the NVMe Management Interface specification.

The new specifications will facilitate the emerging NVMe device ecosystem, including enterprise and client solid state drives (SSDs), removable cards, compute accelerators and HDDs.

Key NVMe 2.0 Features:
  • The ZNS specification provides a zoned storage device interface that allows the SSD and host to collaborate on data placement. ZNS permits data to be aligned to the physical media of the SSD, improving overall device performance and cost while increasing the media capacity that can be made available to the host.
  • The KV Command Set provides access to data on an NVMe SSD controller using a key rather than a block address. KV allows applications to directly communicate with the drive using key-value pairs, avoiding the overhead of translation tables between keys and logical blocks.
  • Namespace Types provides a mechanism to allow an NVMe SSD controller to support the different command sets that are defined as part of the NVMe 2.0 release as well as a path for future command sets.
  • NVMe Endurance Group Management enables media to be configured into Endurance Groups, exposing granularity of access to the SSD and improving control.
  • Rotational Media support enables support for HDD on NVMe technology with updates to features, management capabilities and other enhancements required for HDD support.
  • Multiple Controller Firmware Update defines behavior for firmware updates on complex systems with multiple controllers.
  • Shutdown enhancements enable showdown control from enclosure management for simplified management of many drives at once.
  • Simple Copy Command copies data from one namespace in the drive, offloading the copy operations from multiple source LBAs to a single destination LBA.
  • 32/64 bit CRC expands the protection information and data protection to 32 and 64 bit allowing for new types of meta data use cases.
  • Command Group Control prevents unintended changes after a system is provisioned and protects the system from unintentional or malicious changes.
  • NVMe 2.0 specifications maintain backwards compatibility with previous NVMe generations.
View the NVMe 2.0 library of specifications on our website: https://nvmexpress.org/resources/specifications/.
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22 Comments on NVM Express Announces NVMe 2.0 Specification

#1
lynx29
I used to think I was pretty well versed in the PC tech world, then I read this post.

Then I gave up reading this post.

:ohwell:
Posted on Reply
#2
Caring1
lynx29I used to think I was pretty well versed in the PC tech world, then I read this post.

Then I gave up reading this post.

:ohwell:
You're not alone.
There's so much I don't know, every day is a learning experience.
Posted on Reply
#3
Mussels
Moderprator
Oh yuck they added mechanical drive support, so now we're gunna get flooded with garbage "NVME" systems using spinning rust in reality
Posted on Reply
#4
Jism
MusselsOh yuck they added mechanical drive support, so now we're gunna get flooded with garbage "NVME" systems using spinning rust in reality
Mechnical based storage is still cheaper then SSD's.

However i do believe that the tech by now for consumers is getting outdated.

The reliability of good SSD's on it's own just beat the HDD's completely.
Posted on Reply
#5
R0H1T
MusselsOh yuck they added mechanical drive support,
I don't know about that, there's this beauty in the world spinning. Some kind of harmony that is hard to ignore, a word that just evades me :D
Trolling?
Posted on Reply
#6
Tomorrow
Better question is do existing drives get 2.0 via firmware update?
I doubt most manufacturers will bother. Perhaps Samsung and some others who make top 4.0 drives.
Posted on Reply
#7
R0H1T
TomorrowBetter question is do existing drives get 2.0 via firmware update?
It's a spec, you can't update PCIe 3.0 to v4 can you? Unless the hardware's capable & ideally certified.
Posted on Reply
#8
Tomorrow
R0H1TIt's a spec, you can't update PCIe 3.0 to v4 can you? Unless the hardware's capable & ideally certified.
NVMe 2.0 specifications maintain backwards compatibility with previous NVMe generations.
If its a firmware change that does not require new hardware i dont see why not.
Posted on Reply
#9
R0H1T
PCIe 4.0 is also backwards compatible with 3.0, I think you're confusing compatibility with what the hardware's actually capable of. All NVMe 2.0 drives would be backwards compatible with v1.4 the reverse is not true though, NVMe 1.4 drives may not be capable of v2 specific features.
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#10
Prima.Vera
Is there a simplified English translation for the new features?
Posted on Reply
#11
Wirko
@btarunr
  • Shutdown enhancements enable showdown control from enclosure management for simplified management of many drives at once.
Probably a typo ... but what if it isn't?
lynx29I used to think I was pretty well versed in the PC tech world, then I read this post.

Then I gave up reading this post.

:ohwell:
Ah, so you're that guy who doesn't have a datacenter in his basement? Now we're two.
Indeed, the new features are of most interest to the server world, and this is Anandtech's conclusion, too. We'll see what comes of zoned storage, which may be useful on the client side, some day, too.
TomorrowBetter question is do existing drives get 2.0 via firmware update?
I doubt most manufacturers will bother.
How often do peripherals, of any kind, get many significant new features with firmware updates? There are third party projects like DD-WRT for routers and CHDK for Canon cameras, but what about official firmware?
TomorrowPerhaps Samsung and some others who make top 4.0 drives.
Not drives that exist today but those that come to the market in the near future, like next 6-12 months, before manufacturers implement the new features. Samsung and others would be wise to make them upgradeable, and advertise them as such of course.
Posted on Reply
#12
bonehead123
Caring1You're not alone.
There's so much I don't know, every day is a learning experience
You don't know what you don't know until you figure out that you didn't know what you thought you knew, hahahaha :)
Posted on Reply
#13
Aquinus
Resident Wat-man
btarunrThe KV Command Set provides access to data on an NVMe SSD controller using a key rather than a block address. KV allows applications to directly communicate with the drive using key-value pairs, avoiding the overhead of translation tables between keys and logical blocks.
This is pretty cool, not going to lie. I can see this being pretty useful for databases where the translation between indexed values and their corresponding disk location could be costly.
MusselsOh yuck they added mechanical drive support, so now we're gunna get flooded with garbage "NVME" systems using spinning rust in reality
I would expect something like this to have the equivalent of a SAS to SATA breakout cable if they're going to support rotational media drives.
Posted on Reply
#14
Tomorrow
Wirko@btarunrHow often do peripherals, of any kind, get many significant new features with firmware updates? There are third party projects like DD-WRT for routers and CHDK for Canon cameras, but what about official firmware?
Off the top of my head i can remember monitors with v2 G-Sync module gaining the ability to support AMD cards too. Tho v1 version never had this update.
Or older AM4 motherboards gaining new CPU support and even PCIe 4.0 on B450 althought this was shut down by AMD real quick. There are also some official (beta obviously) AsRock BIOS versions out there that support Ryzen 5000 on select X370 and B350 boards.
Or GPU's gaining ReBAR support via vBIOS update for example. Or older DX11 cards gaining DX12 support (tho this is a bit murky due to "levels" in DX support). Im sure there are other examples of this.
Posted on Reply
#15
RealKGB
I'm imagining NVMe HDDs looking like this:


Posted on Reply
#16
Aquinus
Resident Wat-man
RealKGBI'm imagining NVMe HDDs looking like this:


The thing is that it's a complete waste of an NVMe slot since SATA 6G is plenty fast for hard drives, which makes me think that it's far more likely to be a breakout cable. Think about it, one PCIe lane is plenty for a rotational media drive. 4 lanes would translate to a breakout cable to 4 disks, just like a SAS to SATA breakout cable. I see absolutely no reason to get rid of SATA if it's one NVMe slot to one HDD. There is zero benefit to doing that. However, a breakout cable means you could ditch the SATA ports in favor or something with connectors that can support more than 1 device because you can save some motherboard space in the process. The primary issue is going to be the length of that cable because PCIe signals can't travel indefinitely without signal degradation, so it'll be interesting how it turns out.

Either way, I think it's time that SATA gets retired. I have a socket 478 Celeron machine in the attic with SATA 1.5G which goes to show how old SATA is.
Posted on Reply
#17
Tomorrow
Thats super old. My first board with SATA was s939 and that was SATA-II if im not mistaken.
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#18
Wirko
AquinusThe thing is that it's a complete waste of an NVMe slot since SATA 6G is plenty fast for hard drives, which makes me think that it's far more likely to be a breakout cable. Think about it, one PCIe lane is plenty for a rotational media drive. 4 lanes would translate to a breakout cable to 4 disks, just like a SAS to SATA breakout cable. I see absolutely no reason to get rid of SATA if it's one NVMe slot to one HDD. There is zero benefit to doing that. However, a breakout cable means you could ditch the SATA ports in favor or something with connectors that can support more than 1 device because you can save some motherboard space in the process. The primary issue is going to be the length of that cable because PCIe signals can't travel indefinitely without signal degradation, so it'll be interesting how it turns out.

Either way, I think it's time that SATA gets retired. I have a socket 478 Celeron machine in the attic with SATA 1.5G which goes to show how old SATA is.
NVMe over SAS? Why not. NVMe had an extension (NVMe-oF) which had a purpose to make it usable over Ethernet or other networks, and that was long before version 2.0. Now, the support for rotational media further extends it to local interfaces other than PCI Express. NVMe is a set of protocols, some of them can replace parts of the SAS protocol stack (PDF, page 8) and iSCSI, some are intended for management, but SAS remains the physical layer.

NVMe over SATA? Nah, we're not talking about stuff for consumers here.
Posted on Reply
#19
Mussels
Moderprator
AquinusThe thing is that it's a complete waste of an NVMe slot since SATA 6G is plenty fast for hard drives, which makes me think that it's far more likely to be a breakout cable. Think about it, one PCIe lane is plenty for a rotational media drive. 4 lanes would translate to a breakout cable to 4 disks, just like a SAS to SATA breakout cable. I see absolutely no reason to get rid of SATA if it's one NVMe slot to one HDD. There is zero benefit to doing that. However, a breakout cable means you could ditch the SATA ports in favor or something with connectors that can support more than 1 device because you can save some motherboard space in the process. The primary issue is going to be the length of that cable because PCIe signals can't travel indefinitely without signal degradation, so it'll be interesting how it turns out.

Either way, I think it's time that SATA gets retired. I have a socket 478 Celeron machine in the attic with SATA 1.5G which goes to show how old SATA is.
I hope you're correct and that does make sense - they just want an NVME to sata adaptor, so they dont have to wire up SATA physically to the slots.

I just fear it'll result in prebuilts and laptops with NVME plastered all over them, and turn out to be mech only.
Posted on Reply
#20
Aquinus
Resident Wat-man
Musselsand turn out to be mech only.
Maybe for towers, but I think that's not realistic for laptops when battery life is a key selling point. Forget latency for doing... well, anything. Maybe for cheap pre built towers, but even that seems like a stretch when you're already investing in a controller that can speak PCIe/NVMe. I think most OEMs at this point would rather give you a small SSD than a HDD.
Posted on Reply
#21
Xajel
I hope this mean a near end to the SATA cables. And I really really hope they work more on the power cable for these drives, I mean it's awful how the power connector is much wider than the actual data cable!! Not to mention the main thing of having two cables in the first place.

I wish the next SATA replacement will have at least few watts of power, like <15-20W per drive. And seeing that the new move by the industry is for 12V, this can be done more easily for 2.5" drives as they have plenty of space for a small voltage regulator 12V to 5V & 3.3V. Allowing most consumer grade drives to work with a single cable. And an optional power cable for more powerful drives.

It should also have some sort of PCIe bifurcation, basically a storage controller will looks like a regular PCIe switch. You can't waste x4 lanes on a regular SATA drive even for cheap SATA SSD, a single PCIe 3.0 x1 lane is enough for this. I know next generation of Mechanical HDD's is going to be faster (like the new Seagate Multi-Actuators which reaches 500-600MB/s) which means PCIe 3.0 x1 will be saturated for it, but it won't be saturated except in sustained read performance.

A single cable from the motherboard can go to the drive cage in the case, driving 4 drives in the same time (or even more if that single cable was PCIe 4.0 or 5.0 x4 lanes). Either by splitting the cable, or better, having a drive backbone built in in the case (like standard NAS or external drive bays) allowing for neater looks, better air flow & better data & power management. This will be the perfect use case for storage drives (either SSD or HDD based ones).
Posted on Reply
#22
The red spirit
JismMechnical based storage is still cheaper then SSD's.

However i do believe that the tech by now for consumers is getting outdated.

The reliability of good SSD's on it's own just beat the HDD's completely.
Mechanical storage at this point is dead to consumers, unless all you store are videos or audio files. The main problem with them is that they are so slow that they are unusable. I tried CS:GO on spinning rust and I had to wait 3 or 4 minutes after match has already started to start playing it. I wouldn't want to know how long it takes for any modern AAA game to load on them. IT's just sucks that SSDs are still so expensive and due to that still can't be realistically used for big local storage of stuff.
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