manually umount and mount an nfs volume on esx 5.5

vmware esxi 5.5 says the nfs volume is not accessible. really?

 esxcli storage list  
 yep. not accessible.  
 esxcli storage nfs remove -v nfs-store  
 remove it. do whatever you do to fix the issue. then... re-add per below.  
 esxcli storage nfs add -H 192.168.6.66 -s /data/dev/nfs-store -v nfs-store  
                         ^               ^                      ^  
                         |               |                      |  
                         nfs server      |                      |  
                                         nfs export             |  
                                                            local datastore name