Unable to mount storage from NFS shares due to NFS target being unreachable

Products

• VMware vSphere ESXi

Issue/Introduction

• NFS datastores are not showing up when attempting to mount them to ESXi hosts. 
• vmkping to the NFS target is failing from a vmkernel adapter that appears to be in the same network. 
  • Testing VMkernel network connectivity with the vmkping command

Environment

VMware vSphere ESXi 

Cause

vmkping failure indicates there is a misconfiguration with the IP, VLAN, or MTU. 

Resolution

• Verify that the IP address configured on the vmkernel adapter is in the same subnet as the NFS target. 
  • For example, if the network for your NFS target and vmkernel adapters is a /25 CIDR (subnet mask 255.255.255.128) you have IPs ###.###.###.1 to ###.###.###.128 as available IPs that will be able to communicate with each other over Layer 2. ###.###.###.5 and ###.###.###.200 would not be able to communicate with each other as they are not in the same IP subnet. 
• Verify that the VLAN configuration on the NFS vmkernel port group is correct. 
  
  • Vlan configuration on virtual switches, physical switches, and virtual machines
• Verify that the MTU configured on the vmkernel adapter matches the MTU configured on the virtual switch.