Unable to mount an NFS 4.1 volume

Products

• VMware vCenter Server

Issue/Introduction

When attempting to mount a new datastore using the NFS 4.1 protocol, the operation times out.  The vCenter output could look something like this:

"Operation failed, diagnostics report: Mount failed: Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Timeout: VSI node (5002:)"

The /var/log/vmkernel.log may show error messages like the following:

2026-02-10T20:07:36.307Z In(182) vmkernel: cpu18:2098867 opID=5d030562)NFS41: NFS41FSLocateCluster:4334: nConnect fs->numConns 1
2026-02-10T20:07:36.307Z In(182) vmkernel: cpu18:2098867 opID=5d030562)NFS41: NFS41MultiPathPrepareConnections:916: Address tcp #.#.#.#.8.1. Required conns 1 updateConns 0
2026-02-10T20:07:36.307Z In(182) vmkernel: cpu18:2098867 opID=5d030562)NFS41: NFS41MultiPathPrepareConnections:951: New connections required 1 updateConns 0 createNewConn 0
2026-02-10T20:07:36.307Z In(182) vmkernel: cpu0:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 12532 US delay
2026-02-10T20:07:36.331Z Wa(180) vmkwarning: cpu0:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:36.331Z In(182) vmkernel: cpu0:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 20000 US delay
2026-02-10T20:07:36.352Z Wa(180) vmkwarning: cpu0:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:36.352Z In(182) vmkernel: cpu0:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 40000 US delay
2026-02-10T20:07:36.393Z Wa(180) vmkwarning: cpu0:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:36.393Z In(182) vmkernel: cpu0:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 80000 US delay
2026-02-10T20:07:36.474Z Wa(180) vmkwarning: cpu0:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:36.474Z In(182) vmkernel: cpu0:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 160000 US delay
2026-02-10T20:07:36.635Z Wa(180) vmkwarning: cpu0:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:36.635Z In(182) vmkernel: cpu0:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 320000 US delay
2026-02-10T20:07:36.957Z Wa(180) vmkwarning: cpu1:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:36.957Z In(182) vmkernel: cpu1:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 640000 US delay
2026-02-10T20:07:37.600Z Wa(180) vmkwarning: cpu1:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:37.600Z In(182) vmkernel: cpu1:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 1280000 US delay
2026-02-10T20:07:38.881Z Wa(180) vmkwarning: cpu1:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:38.881Z In(182) vmkernel: cpu1:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 2560000 US delay
2026-02-10T20:07:41.442Z Wa(180) vmkwarning: cpu1:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:41.442Z In(182) vmkernel: cpu1:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 5120000 US delay
2026-02-10T20:07:46.563Z Wa(180) vmkwarning: cpu2:2098175)WARNING: NFS41: NFS41ExidNFSProcess:2140: Server doesn't support the NFS 4.1 protocol
2026-02-10T20:07:46.563Z In(182) vmkernel: cpu2:2098175)NFS41: NFS41IssueExid:1899: Issuing EXCHANGE_ID on Connection tcp:#.#.#.#.8.1 with 10000000 US delay

Environment

VMware vSphere ESXi (All Versions)

Cause

The storage array may not support the NFS 4.1 protocol.  NFSv4.1 is not always included on certain CPU architectures (particularly embedded, low-power, or 32-bit systems) primarily due to memory handling limitations, resource constraints, and complexity in implementing its stateful, parallel, and session-based features.

Resolution

The supportability of NFS 4.1 can be confirmed with the storage vendor.  If NFS 4.1 is not supported, use NFS 3 instead.  The storage vendor may have alternate storage arrays that do support the NFS 4.1 protocol if that is absolutely necessary.  If the storage array model should support NFS 4.1, work with the storage vendor to determine why the host would report that it does not.  If support is required from vSphere, open a case with Broadcom per KB 142884.