The error which you have recieved is due to issues with VMware API integration unable to automatically create the datastore on the ESX host , this issue happens when the VNXe is querying VMware and unable to do it effectively due to some busy resources.What VNXe software code are you currently on ? try it after some time and check if it works,   For manually adding the VNXe NFS Datastore the path can be identified from VNXe Storage > VMware > VMware Details , it is the one given on Summary ' Name:     '  Please use  / on VMware 
Running VNXe3100 and ESXi 4.1.  When we create a new VMWare Datastore, the datastore is created, but throws the following error:  The storage was created successfully on VNXe but the remote datastore creation failed on one or more VMware ESX servers. You need to create the datastores for those VMware ESX servers manually through vCenter or ESX servers (Error Code:0x5c00005)   The above may be causing the next part to fail, but I thought I'd post anyway.  We go into Storage thru vCenter then Add Storage, choose NFS,  Type in IP address etc.  I do have a question here..... How can you determine the exact folder path???  Is there a default?  The example is /vols/vol0/datastorename  But without knowing the location on the local VNXe box (since I have NOT found a way to get SSH access into the server), how do you know exactly what the path should be?  Again, this may be due to step 1 failing with the error above but I'm not sure.  TIA!  
Error Creating VMWare Datastore