6.7

When a virtual machine has a WWN assigned to it, the virtual machine’s configuration file (.vmx) is
updated to include a WWN pair. The WWN pair consists of a World Wide Port Name (WWPN) and a
World Wide Node Name (WWNN). When that virtual machine is powered on, the VMkernel instantiates a
virtual port (VPORT) on the physical HBA which is used to access the LUN. The VPORT is a virtual HBA
that appears to the FC fabric as a physical HBA. The VPORT has its own unique identifier, the WWN pair
that was assigned to the virtual machine.
Each VPORT is specific to the virtual machine. The VPORT is destroyed on the host and it no longer
appears to the FC fabric when the virtual machine is powered off. When a virtual machine is migrated
from one host to another, the VPORT closes on the first host and opens on the destination host.
If NPIV is enabled, WWN pairs (WWPN & WWNN) are specified for each virtual machine at creation time.
When a virtual machine using NPIV is powered on, it uses each of these WWN pairs in sequence to
discover an access path to the storage. The number of VPORTs that are instantiated equals the number
of physical HBAs present on the host. A VPORT is created on each physical HBA that a physical path is
found on. Each physical path determines the virtual path that is used to access the LUN. HBAs that are
not NPIV-aware are skipped in this discovery process because VPORTs cannot be instantiated on them.
Requirements for Using NPIV
If you plan to enable NPIV on your virtual machines, you should be aware of certain requirements.
The following requirements exist:
n
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.
n
HBAs on your host must support NPIV.
For information, see the VMware Compatibility Guide and refer to your vendor documentation.
n
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.
n
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.
n
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.
n
The switches in the fabric must be NPIV-aware.
n
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.
NPIV Capabilities and Limitations
Learn about specific capabilities and limitations of the use of NPIV with ESXi.
vSphere Storage
VMware, Inc. 46