NVMeoverFabrics

NVMe over Fabrics (NVMe-oF) is a specification that extends the NVMe command set to remote storage by carrying NVMe commands and data over network fabrics. It enables servers to access NVMe storage devices as if they were locally attached, even when the storage is physically distant in a data center. The NVMe-oF specification is maintained by the NVM Express organization and defines how NVMe commands are transported, discovered, and mapped to storage namespaces.

NVMe-oF decouples the NVMe protocol from the transport layer, allowing use of high-speed fabrics such as RDMA networks (InfiniBand, RoCE, iWARP) and TCP/IP networks. The most common transport families are NVMe-oF over RDMA and NVMe-oF over TCP, enabling low-latency, high-bandwidth access across data-center fabric networks.

In an NVMe-oF deployment, a host acts as an initiator and presents NVMe devices to the operating system via an NVMe-oF driver. A storage system or array provides one or more NVMe subsystems on the target side, each offering one or more namespaces that map to logical volumes. A discovery controller helps initiators locate available subsystems and namespaces. Initiators connect to a chosen subsystem, attach namespaces, and then issue NVMe I/O commands over the fabric using submission and completion queues.

NVMe-oF is widely used in data centers to scale NVMe performance for virtualization, databases, and hyper-converged infrastructure. It differs from traditional block access protocols such as iSCSI or Fibre Channel by transporting NVMe commands directly over the fabric, reducing translation layers and overhead. Security and management rely on the underlying transport or fabric-specific mechanisms, as NVMe-oF itself does not mandate encryption. Operational considerations include compatible drivers, firmware, and fabric QoS to meet latency and reliability requirements.