First of All thank you for your replies. I erally appreciate it.
Tried the steps asked by Gkeerthy. Below are the results:
Vswitch settings, NIC Teaming is all OK.
~ # esxcli storage nfs list
Volume Name Host Share Accessible Mounted Read-Only
-------------- ------------ ------------------- ---------- ------------- -------- -----------
Dev_Datastore 10.X.X.213 /vol/Dev_Datastore false false false
Prod_Datastore 10.X.X.212 /vol/Prod_Datastore false false false
Test_Datastore 10.X.X.213 /vol/Test_Datastore false false false
NOTE: If I run the same command on other running hosts, It says TRUE instead of false and "Mounted Available" instead on "Unmounted Unavailable".
Also My datastores are not a part of the storage cluster.
Question: What if I run the commandesxcli storage nfs remove -v Dev_Datastore (for each Datastore) and then mount the datastore again? Will it do any good?