vSphere does not report extended size of NFS datastore

Products

• VMware vSphere ESXi

Issue/Introduction

• An NFS share presented to ESXi is extended on the NFS server
  
  
• The vSphere Client reports does not report the extend size of the NFS datastore. It reports the original size.
  
  
• The issue persists after host reboot or datastore unmount and re-mount.

Environment

VMware vSphere ESXi (all versions)

Cause

The NFS server continues to return the original size of the NFS share/datastore to ESXi, after the share is extended.

Verification:
Confirm the NFS share size reported by the NFS server from a packet capture:

1) Initiate a packet capture against the vmkernel port use for NFS, e.g.

tcpdump-uw -i vmkX -s 0 -w /vmfs/volumes/<datastore>/vmkX.pcap 

2) Run:

df -h

3) Stop the packet capture.

4) Filter the packet capture for FSSTAT reply:

e.g.
tshark -2 -Tfields -e frame.number -e frame.time_relative -e rpc.xid -e nfs.fsstat3_resok.tbytes -e nfs.fsstat3_resok.fbytes  -Y 'rpc.procedure == 18 && rpc.msgtyp == 1' -r vmkX.pcap

Sample output per share:
[frame] [relative time] [rpc call]      [capacity in bytes] [available space in bytes]
12843   12.458982000    0x72403048      30334574070180      10551433430436


Alternatively, via Wireshark, filter packets for nfs.fsstat3_resok.tbytes

Resolution

Engage your storage vendor to investigate why the the NFS server does not return the extended share size, and to resolve.