NFS Mount fails Error : Unable to connect to NFS server

Products

• VMware vSphere ESXi

Issue/Introduction

• NFS datastore mount fails with the error: An Error occurred during host configuration. Operation failed, diagnostics report: Mount failed. Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Unable to connect to NFS server

• The log file /var/log/hostd.log may contain the message "Mount failed"

  2025-04-04T17:21:29.102Z error hostd[2101497] [Originator@6876 sub=Hostsvc.FSVolumeProvider opID=######-####-auto-###-##:####-##-#-### user=vpxuser:########/] VmkCtl mount or ProcessNas failed: Mount failed: Unable to complete Sysinfo operation.  Please see the VMkernel log file for more details.: Unable to connect to NFS server
  
  2025-04-04T17:21:29.113Z info hostd[2101497] [Originator@6876 sub=Solo.Vmomi opID=######-####-auto-###-##:####-##-#-### user=vpxuser:#######\#######] Throw vim.fault.PlatformConfigFault
  2025-04-04T17:21:29.113Z info hostd[2101497] [Originator@6876 sub=Solo.Vmomi opID=m1x73n6h-24973346-auto-ev9k3-h5:74274300-2f-8-8493 user=vpxuser:#######\#######] Result:
  --> (vim.fault.PlatformConfigFault) {
  -->    faultMessage = (vmodl.LocalizableMessage) [
  -->       (vmodl.LocalizableMessage) {
  -->          key = "com.vmware.esx.hostctl.default",
  -->          arg = (vmodl.KeyAnyValue) [
  -->             (vmodl.KeyAnyValue) {
  -->                key = "reason",
  -->                value = "Mount failed: Unable to complete Sysinfo operation.  Please see the VMkernel log file for more details.: Unable to connect to NFS server"
  -->             }
  -->          ],
  -->       }
  -->    ],
  -->    text = "",
  -->    msg = ""
  --> }

• The file /var/run/log/vmkernel.log may show a mount failure for the NFS datastore
  
  2025-06-23T08:58:14.955Z In(182) vmkernel: cpu60:2099267 opID=##)SunRPC: 3615: Synchronous RPC cancel for client 0x43########f0 IP ##.###.###.####.0.## proc 3 xid 0x7#####8 attempt 1 of 3
2025-06-23T08:58:24.955Z In(182) vmkernel: cpu60:2099267 opID=##)SunRPC: 3615: Synchronous RPC cancel for client 0x43########f0 IP ##.##.###.1##.0.### proc 3 xid 0x7#####8 attempt 2 of 3
2025-06-23T08:58:34.956Z In(182) vmkernel: cpu60:2099267 opID=##)SunRPC: 3615: Synchronous RPC cancel for client 0x43########f0 IP 10.##.##.1##.0.1## proc 3 xid 0x7#####8 attempt 3 of 3
2025-06-23T08:58:34.956Z In(182) vmkernel: cpu60:2099267 opID=##)StorageApdHandler: 1051: Freeing APD handle 0x43########60 [1######3-c######0]
2025-06-23T08:58:34.956Z In(182) vmkernel: cpu60:2099267 opID=##)StorageApdHandler: 1135: APD Handle freed!
2025-06-23T08:58:34.956Z In(182) vmkernel: cpu60:2099267 opID=##)NFS: 3500: NFS mount failed for <hostname###>:/prd_####### volume ##########. Status: Unable to connect to NFS server.


• Ping to NFS datastore fails:
  
  vmkping -I <vmkernel ID> -s 8972 <NFS server IP>
  
  Results:

PING <NFS server IP>: 8972 data bytes
--- <NFS server IP> ping statistics ---
3 packets transmitted, 0 packets received, 100% packet loss

• Netcat also fails to connect:
  
  nc -zv <NFS server IP>

Results:

nc: connect to <NFS server IP> port 2049 (tcp) failed: Connection timed out

Environment

VMware vSphere ESXi

Cause

The issue occurs due to a connection failure between the NFS server and the ESXi host.

Resolution

Resolve any connection issues between the ESXi host and NFS server, then confirm connectivity.

Validate Network Connectivity:

 

  esxihost# vmkping -I <vmkernel> <NFS_Server_IP>  

  esxihost# nc -vz <NFS_Server_IP> 2049  

Refer to the related KB : NFS Datastore Fails to Mount with "The mount request was denied by the NFS server" Error