For IT industry observers, 2017 will likely be remembered as the year that marked a sea change in enterprise storage. NVMe solid-states drives have been available for a few years, but as their prices have fallen to near-parity with SATA drives, we are now beginning to witness a tidal shift to this newer storage technology. With data centers now migrating to NVMe in significant numbers,[1] what is fueling the shift to these newer drives, and what are the implications of it?

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Figure 1. Enterprises are quickly moving to NVMe and away from SATA1

NVMe Drives 101

NVMe SSDs, like all SSDs, are based on flash memory. The difference between these drives and older SSDs is that NVMe SSDs use a different software protocol and physical interface to send data to the motherboard and CPU.

From a software perspective, the NVMe protocol is new and has been specifically designed to help fulfill the enormous performance potential of SSDs. Compared to the traditional interface alternatives, Serial ATA (SATA) and Serial Attached SCSI (SAS), NVMe is much more efficient. For example, NVMe offers vastly improved queuing (which reduces slow, repeated signaling) and requires lower overhead for error-correction (which allows more of the targeted load to transfer per block of data). The NVMe software protocol also accommodates the capability of SSD drives to send and receive data through multiple channels (called lanes) at once.

Physically, NVMe drives connect to motherboards via the PCIe interface and bus, which currently offers up to 16 lanes of data in the recently released PCIe 4.0 standard. These multiple lanes can connect directly to multiple CPU cores when they are available. Neither SATA nor SAS can match the ability of PCIe to send and receive data over so many lanes.[2]

Performance Improvements with NVMe Drives

The result of these logical and physical interface improvements is that NVMe SSDs can deliver dramatically better performance than SATA or SAS SSDs.

As some readers certainly know, you can measure storage performance in two ways: latency and throughput. Latency essentially refers to how quickly the storage medium responds to a request. Throughput, on the other hand, describes how much data the storage medium can send per second once it begins responding

For both latency and throughput, NVMe drives offer improvements that are far more than incremental. As far as latency is concerned, NVMe offers approximately three-times improvements over SATA and 20 percent improvements compared to SAS.1,[3] For throughput, the highest performing NVMe drives use the PCIe 4.0 standard, which allows data transfer rates of up to 32 Gbps (2 Gbps x 16 PCIe data lanes). Compare that with the 4.8 Gbps limit for SATA drives and 12 Gbps limit for SAS drives. (Note: An upcoming standard for SAS drives to be released in 2017 will push this limit up to 24 Gbps. The next version of PCIe to be released in 2019, though, will offer up to 64 Gbps, which SAS will be unlikely to approach.)

What Does This All Mean?

NVMe SSDs are a big deal because, until now, storage throughput has been the primary bottleneck holding back performance in most servers. With the dramatic improvements offered by NVMe, storage can now keep close pace with today’s server memory and processors.

Reducing latency for public-facing applications can offer a critical competitive advantage. Many studies have shown that latency significantly impacts business.[4] For example, Amazon has reported that every extra 100 ms of latency leads to a 1-percent reduction in sales. Furthermore, for jobs that require the fastest possible response times, such as high-frequency trading, the reduced latency of NVMe drives can amount to millions of dollars lost or saved.

Increasing throughput also has a significant impact. A faster pipeline to data allows significantly faster operations for analytics and artificial intelligence involving large data sets, which can improve the speed of delivering valuable insights for the business itself or for the customer.

Overall, by removing the storage performance bottleneck, NVMe drives improve operational agility and business efficiency. As the prices of these drives continue to drop, these competitive advantages will become difficult to ignore. Expect the NVMe tide to keep rolling in through the next couple of years.

To learn more about NVMe SSDs, visit https://www.intel.com/content/www/us/en/solid-state-drives/intel-ssd-dc-family-for-nvme.html?wapkw=nvme.

[1] EE Times. “The Competitive Advantage of NVMe SSDs in the Data Center.” May 2017. www.eetimes.com/author.asp?section_id=36&doc_id=1331774.

[2] For a more complete list of improvements in NVMe, see www.datacenterjournal.com/answer-nvme-questions.

[3] The Register. “You keep using that word – NVMe. Does it mean what I think it means?” April 2016. www.theregister.co.uk/2016/04/11/nvme_fabric_speed_messaging.

[4] High Scalability. “Latency Is Everywhere And It Costs You Sales – How To Crush It.” July 2009. http://highscalability.com/latency-everywhere-and-it-costs-you-sales-how-crush-it.

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