What is NVMe over Fabrics (NVMe-oF)?

Technical Overview

NVMe over Fabrics (NVMe-oF) was introduced by NVM Express, Inc. as a companion specification to the base NVMe standard, first published in 2016. The NVMe command set was originally designed for PCIe-attached local SSDs, where the host CPU directly writes commands into submission queues mapped in the device's PCIe BAR. NVMe-oF extends this model across a network fabric by defining a transport-agnostic capsule format that carries NVMe command and data PDUs over any supported fabric transport.

Three transport bindings are currently standardized: NVMe/RDMA (using InfiniBand or RoCE), NVMe/FC (Fibre Channel), and NVMe/TCP. Each binding specifies how NVMe capsules are encapsulated within the respective transport's PDU format. The specification also defines discovery controllers — special NVMe subsystems that respond to discovery log page requests, allowing initiators to enumerate available subsystems and namespaces on a fabric without prior out-of-band configuration.

The NVMe-oF model retains the full NVMe command set semantics: multi-queue parallelism, fused operations, reservations, and namespace management commands all work over the fabric exactly as they do locally. This means applications and storage stacks that support NVMe locally can transparently migrate to fabric-attached storage with minimal software changes.

How It Relates to NVMe/TCP

NVMe/TCP is one of three transport bindings defined under the NVMe-oF umbrella. It is the most operationally accessible binding because it requires no specialized NICs or switches — any standard Ethernet infrastructure is sufficient. For Kubernetes environments adopting NVMe-oF, NVMe/TCP has become the dominant choice precisely because of this infrastructure compatibility. simplyblock.io leverages the NVMe-oF architecture to deliver Kubernetes-native block storage over NVMe/TCP, making high-performance shared storage available to container workloads across commodity hardware.

Key Characteristics

• Transport bindings: NVMe/TCP, NVMe/RDMA (IB and RoCE), NVMe/FC
• Discovery: Built-in discovery controller mechanism for fabric-wide namespace enumeration
• Queue model: Inherits NVMe's multi-queue architecture (up to 64K queues)
• NQN format: NVMe Qualified Names identify subsystems (e.g., nqn.2014-08.org.nvmexpress:uuid:...)
• Specification: Part of NVMe 2.0 base spec (TP8000 originally, now integrated)
• Namespace sharing: A single namespace can be shared across multiple hosts (with ANA — Asymmetric Namespace Access)

NVMe-oF Transport Bindings Compared