NVMe 2.0 Brings Support for PCIe-Connected Hard Disk Drives

The new NVM Express 2.0 (NVMe 2.0) Protocol has been released. While the thrust of the protocol focuses on flash storage and networking, the latest additions include full-blown support for hard disk drives (HDDs).

The addition of hard drive support is one of the biggest changes coming to NVMe 2.0 and something most people will be surprised to see, as current 7200-RPM hard drives cannot fully saturate current SATA 3.0 connections. However, like other forms of tech, hard drives are evolving, which might eventually require a bandwidth upgrade beyond SATA 3.0 speeds. For instance, Seagate announced two weeks ago that it's Mach.2 hard drives can reach up to 524MB/s, a speed previously only capable with SSDs.

Drives like the Mach.2 could become very popular over the next few years, as hard drive capacity escalates beyond 20TB to fulfill the needs of the enterprise and data center world. Drives like these will need significantly higher bandwidth to ensure that accessing more than 20TB of data won't take long.

However, simplifying the ecosystem down to one storage connection seems to be the main impetus for adding hard drive support, particularly as the NVMe spec continues to evolve its NVMeoF (NVME over Fabrics) functionally that allows the drives to be networked without additional abstraction layers.

NVMe 2.0 hard drive support could also signal the beginning of a decline of the SATA protocol as a whole since the protocol has not been updated in over 12 years. Getting rid of SATA and migrating all hard drives to NVMe could free up some space on motherboards and simplify storage connections (at least in the consumer space) to just NVMe, but don't expect that change to happen any time soon – the latest word in the storage industry is that it will take a few more years before we see NVMe HDDs ship in high volumes. 

Here's the rest of the NVMe 2.0 feature set. Overall, these features aim to reduce NVMe's overhead and give your PC more control over your SSD.

• Zoned Namespaces (ZNS) is coming to NVMe 2.0 and will allow the SSD and host to collaborate data placement within the drive itself. ZNS will permit data to be aligned to the physical media of the SSD which will improve overall system performance and give your PC more of the SSD's storage capacity.
• NVMe Key-Value Command Set will provide access to data on an NVMe SSD namespace using a key instead of a logical block address. Switching from logical blocks to keys will reduce overhead by not having the SSD maintain a translation table for the logical block address.
• Rotational media support is the name for Hard Disk Drive support for NVM Express. This will include new updates to features and enhancements required for HDD support.
• NVMe Endurance Group Management will enable media to be configured into Endurance Groups and NVM Sets. This exposes granularity of access to the SSD and improved control.
• NVMe 2.0 will be backward compatible with previous NVMe architecture generations. Allowing future NVMe 2.0 SSDs to work with current M.2 capable motherboards and M.2 cards.