What is NVMe

Boost Your Data Transfer Rate: Understanding What is NVMe?

Boost Your Data Transfer Rate: Understanding What is NVMe? - Table of contents:

Solid-state drives have faster read and write speeds than mechanical hard drives. Most machines use the SATA bus standard, and the actual maximum transmission is about 600MB/s. The actual transmission speed of SSDs that support PCIe bus and NVMe protocol will exceed 1000MB/s.

What is NVMe? Let’s learn about NVMe together.

What is NVMe

What is NVMe?

NVMe is the abbreviation of non-volatile memory express, which translates to the non-volatile memory host controller interface specification. When it was first launched on the market, many people thought it was just a new, faster SSD. But in reality, NVMe is a new storage protocol created from the ground up based on performance, which can allow us to take full advantage of the speed of SSD and storage class memory (SCM).

NVMe is a high-performance, NUMA (Non-Uniform Memory Access) optimized, highly scalable storage protocol for connecting host and memory subsystems.

NVMe is specially designed for non-volatile storage such as NAND and flash memory. The NVMe protocol is built on high-speed PCIe channels.

What is NVMe

The functions of the NVMe interface protocol include:

* Support 64K command queue;
* Can send 64K commands per queue using low CPU cycles;
* The delay is about 2.8 microseconds;
* Can directly communicate with the system CPU;
* NVMe can achieve more than one million IOPs

The evolution of NVMe

Storage technology has changed dramatically over the past decade. As SSDs begin to replace HDDs as primary storage devices, a new interface standard is urgently needed to take advantage of the increased speed and functionality.

The traditional SATA interface and AHCI standard are actually designed for mechanical hard disks. The performance of early SSDs was not high. Even if these traditional interfaces and protocols were used, there was no problem.

However, as the performance of SSDs gradually increased, traditional Standards are no longer applicable, which in turn has become a major bottleneck limiting SSDs. NVMe is the first protocol to truly meet the needs of high-speed storage media.

What is NVMe

In the second half of 2009, the NVM Express working group (NVMHCI) began to formulate NVMe specifications. The NVM Express working group included more than 90 company members, and Intel was the main leader. The team members included Micron, Dell, Samsung, Marvell, NetApp, EMC, IDT, and other companies, the purpose is to establish a new storage specification standard for SSD so that it can be liberated from the old SATA and AHCI.

In 2011, the NVMe 1.0 standard was officially released. This standard is tailored according to the characteristics of flash memory storage. The new standard removes various restrictions imposed on SSD by the old standard. Versions 1.1, 1.2, and 1.3 were successively launched in 2012, 2014, and 2017, and the latest NVMe 1.4 standard was released in July 2019.

How does NVMe work?

NVMe maps I/O commands and responses to the host’s shared memory through the PCIe interface. The NVMe interface supports multi-core processor parallel I/O to facilitate high throughput and relieve CPU pressure.

Compared with SCSI and ATA command sets, NVMe provides a more simplified command set to handle I/O requests. Compared to the former two, NVMe requires half the number of CPU instructions.

The essence of NVMe is to establish a path between multiple computers and storage devices. NVMe supports 64,000 commands in a single message queue and up to 65,535 I/O queues.

What is NVMe

In comparison, the queue depth of SAS devices typically supports up to 256 commands in a single queue, and SATA drives support up to 32 commands. For example, if SATA is an ordinary trail that can only pass 32 vehicles at a time, then NVMe is a highway with 65,535 lanes, and each lane can pass 65,535 vehicles.

Advantages of NVMe

The advantage of NVMe is its ability to take advantage of parallel data paths, which provides better performance in terms of acceleration. It enables existing applications as well as new applications to work more efficiently. In addition, low latency, low power consumption, and high compatibility are also one of the many advantages of NVMe.

What is NVMe

The advantages of NVMe include:

  • Low latency, the NVMe protocol can be directly connected to the CPU through the PCIe channel, and the data does not need to be transferred to the CPU through the controller like SATA;
  • IOPS is greatly increased, and NVMe can increase the maximum queue depth from 32 to 64,000, and the IOPS capability of SSD will also be greatly improved.
  • Lower power consumption, NVMe has added automatic power consumption state switching and dynamic energy management functions;
  • High compatibility, NVMe SSD can be easily matched with different platforms, systems, and electronic equipment (E.g. wall mount all in one pc touch screen), and can work normally without the corresponding driver provided by the manufacturer.
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NVMe is also a key enabler of innovation and developing technologies and applications such as the Internet of Things (IoT), artificial intelligence (AI), and machine learning (ML), which can all benefit from low latency and high-performance storage.

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The communication drivers and interface between NVMe and SATA are completely different as SATA uses AHCI drivers that are designed for hard disk drives (HDD) with spinning technology while the NVMe driver is specifically designed for SSDs with flash technology.

Read/write speeds of the top NVMe SSDs on the market can exceed 3000 MB/s (3 GB/s), with some Gen 4 NVMe PCIe SSDs capable of 7500 MB/s.

The top SATA SSDs clock in around 550 MB/s, so NVMe SSDs are far and away the fastest transfer speeds for any SSDs on the consumer market