iSER iSCSI-over-RDMA target transport for InfiniBand and RoCE
The kernel-side target (server) for iSER, which is iSCSI carried over RDMA fabrics such as InfiniBand and RoCE. It lets a Linux storage server export block devices to initiators across high-speed Mellanox/NVIDIA ConnectX and BlueField adapters with much lower CPU overhead than ordinary TCP-based iSCSI, and is used in enterprise SAN and HPC storage deployments.
recommendation
Worth keeping but flagging as a niche feature. The code is still being actively maintained, with patches landing as recently as late 2025 and early 2026, and the underlying ConnectX-4/5/6 and BlueField hardware remains current and sold by NVIDIA. However, iSER target deployments are a specialized enterprise and HPC storage niche, and NVIDIA has begun shifting new RDMA software features into its DOCA-OFED stack starting in 2025, so real-world usage is modest and worth documenting as such.
repository signals
sources
- lore.kernel.org
IB/isert received an explicit upstream patch in November 2025, indicating the code is still maintained.
- lore.kernel.org
ib_isert.c was touched again in January 2026 by RDMA/core work, showing continued integration with active RDMA changes.
- docs.nvidia.com
NVIDIA's 2024 MLNX_OFED documentation still lists iSER under Storage Protocols and states new RDMA software features moved into DOCA-OFED starting January 2025, so the use case remains part of current vendor-supported RDMA stacks.
- docs.nvidia.com
NVIDIA documents support for modern ConnectX-4/5/6 and BlueField adapter families, indicating the underlying RDMA hardware class is still current rather than obsolete.
codex reasoning notes (technical)
Local source inspection via shell (`rg`, `sed`) identified this as the in-kernel iSER target transport (`MODULE_DESCRIPTION` and Kconfig). `lore_file_timeline` on `drivers/infiniband/ulp/isert/ib_isert.c` showed steady activity through 2025-2026, with recent lore URLs above; reviewed recent subjects were maintenance/integration, not removal. Two narrower removal-subject `lore_regex` attempts timed out, so no stronger negative claim is made. Web search + `open` on NVIDIA docs showed iSER still documented in current RDMA software stacks and modern ConnectX/BlueField families still supported. Conclusion: niche enterprise/HPC storage target deployments persist, but usage is specialized and likely low-volume; keep the driver, annotate it as niche rather than deprecate/remove.