N_Port Virtualization ( is an ANSI T11 standard that describes how a single Fibre Channel Physical HBA port can register with a fabric using several worldwide port names (WWPNs), what might be considered Virtual WWNs. This in turn means that since there are multiple Virtual HBAs per physical HBA, we can allow WWNs to be assigned to each VM.
An advantage I see from VMs having their own WWNs is possibly Quality of Service (QoS) measurement. With each VM having its own WWN, you could perceivably track Virtual Machine traffic in the fabric if you had the appropriate tools. Masking and zoning could be configured per virtual machine vice per adapter. Also, you may get more visibility of VMs at the storage array level. But you have to use Raw Device Mappings (RDMs) mapped to the VM for NPIV, which means you do not get all the benefits associated with VMFS and VMDKs
If you plan to enable NPIV on your virtual machines, you should be aware of certain requirements.
The following requirements exist:
-NPIV can be used only for virtual machines with RDM disks. Virtual machines with regular virtual disks use the WWNs of the host’s physical HBAs.
-HBAs on your host must support NPIV.
See the vSphere Compatibility Guide and refer to your vendor documentation for more information.
-Use HBAs of the same type, either all QLogic or all Emulex. VMware does not support heterogeneous HBAs on the same host accessing the same LUNs.
-If a host uses multiple physical HBAs as paths to the storage, zone all physical paths to the virtual machine. This is required to support multipathing even though only one path at a time will be active.
-Make sure that physical HBAs on the host have access to all LUNs that are to be accessed by NPIV-enabled virtual machines running on that host.
-The switches in the fabric must be NPIV-aware.
-When configuring a LUN for NPIV access at the storage level, make sure that the NPIV LUN number and NPIV target ID match the physical LUN and Target ID.
-Use the vSphere Client to manipulate virtual machines with WWNs.