Just for kicks, I upgraded my mirror target filer to 7.3.3 and tried this again and it didn't work. Below is the command and the error that I'm getting. I'm connected to the filer using RPC, and can execute other commands against the filer except the add and remove nalunmap commands. I can run a get-nalunmap command just fine, just can't manipulate the mapping.
PS C:\Windows\system32> Add-naLunMap -Path /vol/Chatesthv/Chatesthv.lun -InitiatorGroup viaRPC.iqn.1991-05.com.microsoft
:mmatlhyperv2.law.millermartin.com -Controller Filer6
Add-NaLunMap : API invoke failed.
At line:1 char:13
+ Add-naLunMap <<<< -Path /vol/Chatesthv/Chatesthv.lun -InitiatorGroup viaRPC.iqn.1991-05.com.microsoft:mmatlhyperv2.l
aw.millermartin.com -Controller Filer6
+ CategoryInfo : InvalidOperation: (NetApp.Ontapi.Filer.NaController:NaController) [Add-NaLunMap], NaExce
ption
+ FullyQualifiedErrorId : ApiException,DataONTAP.PowerShell.SDK.Cmdlets.Lun.AddNaLunMap
Add-NaLunMap : API invoke failed.
At line:1 char:13
+ Add-naLunMap <<<< -Path /vol/Chatesthv/Chatesthv.lun -InitiatorGroup viaRPC.iqn.1991-05.com.microsoft:mmatlhyperv2.l
aw.millermartin.com -Controller Filer6
+ CategoryInfo : InvalidOperation: (NetApp.Ontapi.Filer.NaController:NaController) [Add-NaLunMap], NaExce
ption
+ FullyQualifiedErrorId : LunListInfoFailed,DataONTAP.PowerShell.SDK.Cmdlets.Lun.AddNaLunMap
-Luther