Non-Volatile Memory Express (NVMe) over Fabrics is a protocol designed to connect hosts to storage across networks and other interconnects. This technology is a significant advancement in the field of cloud computing, offering high-speed data transfer rates, low latency, and efficient CPU utilization. In this glossary entry, we will delve deep into the intricacies of NVMe over Fabrics, its history, use cases, and specific examples.
Understanding NVMe over Fabrics requires a basic understanding of NVMe itself. NVMe is a protocol designed to connect a host computer to a solid-state drive (SSD) via a high-speed Peripheral Component Interconnect Express (PCIe) bus. NVMe over Fabrics extends this functionality over a network, allowing for faster and more efficient data transfer between hosts and storage devices.
Definition and Explanation
NVMe over Fabrics, often abbreviated as NVMe-oF, is a protocol that allows for the use of NVMe commands over a network. This is achieved by encapsulating NVMe commands within a message and sending this message over a network to a remote device. The remote device then decapsulates the message, executes the NVMe command, and sends a response back to the host.
The 'Fabrics' in NVMe over Fabrics refers to the network infrastructure used to connect the host to the storage. This could be Ethernet, Fibre Channel, or InfiniBand, among others. The use of these networks allows for the extension of NVMe's high-speed, low-latency capabilities over greater distances than would be possible with a direct PCIe connection.
Components of NVMe over Fabrics
NVMe over Fabrics consists of several key components. The first is the NVMe host, which initiates NVMe commands. The second is the NVMe controller, which receives and processes these commands. The third is the fabric itself, which facilitates communication between the host and controller.
The NVMe host and controller communicate using a protocol known as the NVMe Transport. This protocol defines how NVMe commands are encapsulated within messages and sent over the fabric. There are several types of NVMe Transports, each designed for a specific type of fabric.
Benefits of NVMe over Fabrics
NVMe over Fabrics offers several significant benefits over traditional storage networking protocols. The first is speed. NVMe over Fabrics can deliver data transfer rates that are orders of magnitude faster than those achievable with traditional protocols. This is due to the efficient design of the NVMe protocol, which minimizes CPU overhead and maximizes parallelism.
The second benefit is scalability. NVMe over Fabrics can support thousands of simultaneous connections, making it well-suited for large-scale cloud computing environments. The third benefit is flexibility. NVMe over Fabrics can be used with a variety of fabrics, allowing it to be tailored to the specific needs of a given environment.
History of NVMe over Fabrics
The development of NVMe over Fabrics was driven by the need for a high-speed, low-latency storage networking protocol that could keep pace with the increasing performance of SSDs. Traditional storage networking protocols, such as iSCSI and Fibre Channel, were not designed with the speed and parallelism of SSDs in mind, resulting in a performance bottleneck known as the 'I/O blender effect'.
The NVMe protocol was developed to address this issue. By connecting the host directly to the SSD via a high-speed PCIe bus, NVMe was able to bypass the I/O blender effect and deliver unprecedented performance. However, this direct connection limited the distance over which NVMe could be used.
Development and Standardization
The NVMe over Fabrics protocol was developed to extend the benefits of NVMe over greater distances. The first version of the NVMe over Fabrics specification was released by the NVM Express organization in 2016. This specification defined how NVMe commands could be encapsulated within messages and sent over a network, effectively extending the NVMe protocol over a fabric.
Since then, the NVMe over Fabrics specification has been revised several times, with each revision adding new features and improvements. The most recent revision, NVMe over Fabrics 1.4, was released in 2020 and includes features such as enhanced error reporting and improved support for multi-path I/O.
Use Cases of NVMe over Fabrics
NVMe over Fabrics is used in a variety of applications, particularly in large-scale cloud computing environments. One common use case is in disaggregated storage architectures, where storage resources are separated from compute resources and connected via a network. In these architectures, NVMe over Fabrics can be used to provide high-speed, low-latency access to storage resources.
Another use case is in hyper-converged infrastructures, where compute, storage, and networking resources are combined in a single system. In these systems, NVMe over Fabrics can be used to connect the various components, allowing for efficient data transfer and improved performance.
Specific Examples
Several companies have implemented NVMe over Fabrics in their products. For example, Intel's Storage Performance Development Kit (SPDK) includes support for NVMe over Fabrics, allowing developers to build high-performance storage applications that can take advantage of this technology.
Another example is NetApp, which has integrated NVMe over Fabrics into its AFF A800 storage system. This system uses NVMe over Fabrics to provide high-speed access to storage, delivering performance that is up to six times faster than traditional all-flash arrays.
Conclusion
NVMe over Fabrics is a transformative technology that is reshaping the landscape of cloud computing. By extending the benefits of NVMe over a network, it offers unprecedented speed, scalability, and flexibility. As the demand for high-performance storage continues to grow, the importance of NVMe over Fabrics is only set to increase.
Whether you're a software engineer looking to build the next generation of cloud applications, or a system administrator seeking to optimize your storage infrastructure, understanding NVMe over Fabrics is essential. With its combination of high performance, scalability, and flexibility, it represents the future of storage networking.