NFS Datastore Fails to Mount with error "The NFS server denied the mount request"

Products

• VMware vSphere ESXi

Issue/Introduction

• Mounting a NFS datastore to an ESXi host fails with the following error message:

  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.: The NFS server denied the mount request: VSI node (5001:)

• var/run/log/vmkernel.log on ESXi host reports error "The mount request was denied by the NFS server"

YYYY-MM-DDTHH:MM cpu88:2101111 opID=8a38####) StorageApdHandler: 1051: Freeing APD handle 0x431df7###### [f191d282-######]
YYYY-MM-DDTHH:MM cpu88:2101111 opID=8a38####) StorageApdHandler: 1135: APD Handle freed!
YYYY-MM-DDTHH:MM cpu88:2101111 opID=8a38####) NFS: 194: NFS mount <NFS_Server_IP-address>:<share_path> failed: The mount request was denied by the NFS server. Check that the export exists and that the client is permitted.

• Existing NFS datastore might show as inaccessible in the vCenter UI.

Environment

• ESX 9.x
• ESXi 8.x
• ESXi 7.x

Cause

The issue occurs due to access restrictions or misconfiguration on the NFS server. The NFS server may deny the mount request if:

• The NFS export does not exist.
• The ESXi host do not have permission to access to the NFS share.

Resolution

Note: Ensure NAS Servers are listed in the Broadcom Compatibility Guide and the NFS server configuration aligns with the guidelines and requirements for NFS storage with ESXi: NFS Server Configuration.

1. Verify NFS Server Configuration:

• • Validate the NFS export path exists in the NFS server.
  • Ensure the ESXi host has been granted appropriate permissions in the NFS server.

     2.Validate Network Connectivity:

• • Ensure the ESXi host can communicate with the NFS server by running the following commands from the Host's ESX CLI:

vmkping -I <vmk#> <NFS_Server_IP>  

nc -vz <NFS_Server_IP> 2049 

     3. Check Firewall Rules and Export Settings:

• • Verify that there are no firewall rules blocking the connection between the ESXi host and the NFS server.
  • On the storage side, verify that the ESXi host's IP or subnet is explicitly permitted in the NFS export configuration to ensure the host has the necessary access rights. In NetApp, this configuration can be seen under "NFS Export Policies".

     4. If the above checks do not resolve the issue, engage the storage vendor to review and correct the access settings on the NFS server.

• After resolving the permission issue, attempt to mount the NFS datastore.
  
  
  • Use the following command to mount the NFS datastore from the Host's ESX CLI:

esxcli storage nfs add --host=<NFS_Server> --share=<NFS_Share_Path> --volume-name=<Datastore_Name>

Additional Information

If connectivity issues are observed between the ESXi host and NFS storage, investigate the connectivity issue by referring KB: Troubleshooting NFS datastore connectivity issues