Brief introduction
NVMe is designed to meet the needs of businesses and customers systems using PCIe-based solid-state storage, and optimization of a well-designed, efficient, scalable host controller interface. NVMe is a non-volatile memory (NVM) build from scratch a new technology aimed beyond the Dark Ages hard disk drive technology. From today's NAND flash technology into the future of high-performance, long-lasting memory technology to build these storage devices with non-volatile memory, NVMe the design of these non-volatile memory (NVM) storage device built to provide efficient access to.
There are several performance indicators NVMe trying to solve, including bandwidth, IOPs, delay. For example, the maximum possible IOPs Serial ATA 200000 [200,000], and NVMe device has proven to be more than 1 million [1000000] IOPs. And by supporting PCIe network (e.g., RDMA, FC) NVMe capable of supporting a lot higher than the bandwidth of SATA or SAS (e.g., PCIe Gen3 x4 reach 4GB / s). Next-generation memory technology may enable read access latency less than a microsecond, it requires new agreement includes software stack can be less than 10 microseconds, including end to end delay.
For storage, from hardware to software stack devices and systems, NVMe is a new architecture.
History and signs
NVMe agreement advantage
NVMe as a storage protocol, designed from scratch to be a non-volatile memory (NVM), comprising current and next-generation technology NVM NAND flash technology. Therefore, it did not do the same restrictions as the storage protocol designed for the hard disk drive.
NVMe protocol supports a plurality of queue depth, which is an improvement over traditional SAS and SATA protocol. Typical SAS device supports a maximum of 256 commands in a queue, and the SATA device supports up to 32 commands. The technology for hard disk drives is enough, but can not take full advantage of current and next-generation NVM technology.
On the contrary, NVMe support each command queue 64K supports up to 64K queues. These queues designed such that I / O commands and responses to these commands on the same processor core, and may utilize parallel processing capabilities of multicore processors. Each application or thread can have its own separate queues, so no I / O lock. NVMe also supports MSI-X interrupt control, which can prevent the level of CPU bottlenecks and scalability to support large-scale expansion in the system.
In addition, the NVMe streamlined and has a simple set of commands that use less than half of SAS or SATA CPU instructions to process I / O requests, provide higher IOPS per CPU cycles and lower stack software in the host I / O latency. NVMe also supports enterprise features (such as booking) and client characteristics (such as power management), will improve the efficiency extends beyond the I / O.
Interface type and power
NVMe protocols focus on storage, it can be processed in various forms of interfaces. These include:
- M.2 form
- U.2 2.5-inch drive form (previously called SFF-8639)
- Add-in PCIe卡（AIC）
NVMe power range from full power to low power devices enterprise mobile devices. NVMe further advantage of the processor power state.
Operating System Support
In what context has support NVMe.
Storage Security
NVMe by supporting tunneling protocols to address current data privacy issues, the agreement provides security features and other relevant community-generated Trusted Computing Group (TCG).
Plans for NVMe devices and systems provide features include simple access control, static data protection, password, erase, erase and clear the level of other functions.
For additional information about NVMe storage security, see the Trusted Computing Group and NVM Express Joint White Paper: TCG storage, Opal and NVMe, available at http://www.nvmexpress.org/white-papers/
to sum up
NVMe is rapidly gaining recognized by consumers and suppliers. Some industry analysts predict, NVMe will become the mainstream storage interface in the coming years. Because of the availability of its high performance and low latency characteristics, as well as almost all platforms, NVMe is an industry changer process.
And ever different storage protocols, storage devices and storage subsystems for the first time with the fundamental operation of the host of different ways. Streamlined instruction, software stack lower latency, parallelism and larger queues queue depth, and non-volatile memory design, a previously unheard of I / O and throughput, as well as ever lowest latency storage.