RNBD remote block device over RDMA
A pair of client and server modules that export block storage across the network using RDMA transports such as InfiniBand, RoCE, and iWARP, layered on top of the RTRS transport library. It lets a server expose raw block devices to remote clients with very low latency, and is used in datacenter and HPC storage setups built on modern RDMA NICs like NVIDIA's ConnectX family.
recommendation
It should stay because the code is actively maintained, with patches still landing upstream in 2026 and fixes being backported to stable kernels, indicating real deployments. The underlying RDMA hardware it targets is still sold new, though RNBD itself is a niche datacenter feature rather than something most Linux users will encounter.
repository signals
sources
- lore.kernel.org
RNBD is still seeing upstream maintenance in 2026; a linux-block patch added lock-context annotations to rnbd.
- lore.kernel.org
RNBD client fixes were backported to stable in January 2026, indicating the code is maintained and deployed enough to warrant stable support.
- kernel.org
Kernel documentation describes RNBD as an RDMA Network Block Device over RTRS using RDMA transports such as InfiniBand, RoCE, and iWARP.
- docs.nvidia.com
Modern RDMA-capable adapter families were still current in the mid-2020s, supporting the underlying hardware class RNBD depends on.
codex reasoning notes (technical)
Local Kconfig/README inspection via shell shows RNBD is a real block driver pair (client/server) for remote block over RTRS on RDMA. lore_file_timeline and lore_activity tool calls showed frequent recent touches through 2026-03 and stable backports in 2026-01, with no evidenced removal/deprecation thread; lore_regex attempts for removal signals timed out rather than producing hits. kernel.org RNBD admin-guide URL and NVIDIA ConnectX-7 URL are canonical recall sources used for deployment context; together they support that RNBD targets still-sold RDMA hardware, but as a niche datacenter feature rather than mass-market storage hardware.