SSDs based on original memory use the existing interface, SATA and SAS, as well as protocols and objects that may have little effect on existing storage systems. However, none of these are built for high-speed storage, which is why SSDs end up using PCI-Express display Although it was not designed for this, it is very fast.
The major advantage of using the PCI-Express interface is that they connect directly to the processor, providing access times such as those of RAM, and the first PCD-Express SSDs that have been around for a long time. However, these are SSDs they needed a specific firmware
What is NVMe?
NVMe stands for "Non-Volatile Memory Express," or nonvolatile memory expression. Very efficient, efficient, storage, and high-risk NUMA (Non Uniform Memory Access) storage that connects to a low memory provider. This is an agreement built from scratch and specifically for storage systems, for a purpose always provide excellent performance.
NVMe protocol established on the PCI-Express program channels, which provides not only broad bandwidth that allows for vertigo speed, many times higher than SATA, but access times are significantly reduced because they are directly connected to the processor and, in addition, the probability of escalation and climbing is large. In other words, this is a way of working is for long-term use
Why is it so fast? Understanding the I / O lines
To understand how this protocol works and, above all, how it works to achieve these speed levels, it is necessary to delve a little into its design and, in particular, to understand how I / O queue (input and output).
NVMe can support multiple output lines, up to 64K lines and 64K support entries (By comparison, SATA supports only one line and in some it can only have 32 entries). Software management software can create queues up to the maximum allowed by the administrator in terms of program configuration and workload; Also, it supports I / O streaming / compilation, reduces the effect this has on the data transfer processor load, and also provides advanced converter capabilities in terms of service requirements.
In the above diagram you have a very simple way of communicating between the host and the NVMe host. This build functionality allows applications to start, run and end multiple input or output applications at the same time and without affecting the processor's performance.
In short: The NVMe protocol was created from scratch specially for high-performance storage systems, so it reaches speeds that make full use of PCI-Express observations without overloading the processor. In addition, it is optimized to be able to modify the firmware easily, which means we will continue to use it in the medium and long term because it has the ability to continue to appear without any problem.