Inserting a new host in an ESX Cluster and mapping an NFS share to it produced an interesting result. vCenter showed 2 datastores w/ similar names. 1 w/ 48 hosts mapped to it and another w/ my 1 new host mapped to it. The names were the same albeit one having a "(1)" appended to it. Attempting to change the new one would result in error stating that a datastore already exists w/ that name.
Something as minor as an extra '/', servername.local vs. servername, or IP instead of name, makes ESX treat those mapped NFS shares as completely different even if they all point to the same end point.
Both of these are valid paths to a NFS share in ESX and they both connect to the same resource, but because of one having a FQDN ESX treats them as different shares completely.
Use PowerCLI to map NFS shares (or host profiles if you're licensed for them)
In the script above, if you want to see the nfs share information before you apply it do this after running the lines 1 - 3: