vSphere Storage - ESXi 5.0 - Documentation - VMware
vSphere Storage - ESXi 5.0 - Documentation - VMware
vSphere Storage - ESXi 5.0 - Documentation - VMware
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<strong>vSphere</strong> <strong>Storage</strong><br />
If NPIV is enabled, WWN pairs (WWPN & WWNN) are specified for each virtual machine at creation time.<br />
When a virtual machine using NPIV is powered on, it uses each of these WWN pairs in sequence to try to<br />
discover an access path to the storage. The number of VPORTs that are instantiated equals the number of<br />
physical HBAs present on the host. A VPORT is created on each physical HBA that a physical path is found<br />
on. Each physical path is used to determine the virtual path that will be used to access the LUN. Note that<br />
HBAs that are not NPIV-aware are skipped in this discovery process because VPORTs cannot be instantiated<br />
on them.<br />
Requirements for Using NPIV<br />
If you plan to enable NPIV on your virtual machines, you should be aware of certain requirements.<br />
The following requirements exist:<br />
n NPIV can be used only for virtual machines with RDM disks. Virtual machines with regular virtual disks<br />
use the WWNs of the host’s physical HBAs.<br />
n HBAs on your host must support NPIV.<br />
For information, see the <strong>vSphere</strong> Compatibility Guide and refer to you vendor documentation.<br />
n Use HBAs of the same type, either all QLogic or all Emulex. <strong>VMware</strong> does not support heterogeneous<br />
HBAs on the same host accessing the same LUNs.<br />
n If a host uses multiple physical HBAs as paths to the storage, zone all physical paths to the virtual<br />
machine. This is required to support multipathing even though only one path at a time will be active.<br />
n Make sure that physical HBAs on the host have access to all LUNs that are to be accessed by NPIVenabled<br />
virtual machines running on that host.<br />
n The switches in the fabric must be NPIV-aware.<br />
n When configuring a LUN for NPIV access at the storage level, make sure that the NPIV LUN number and<br />
NPIV target ID match the physical LUN and Target ID.<br />
n Use the <strong>vSphere</strong> Client to manipulate virtual machines with WWNs.<br />
NPIV Capabilities and Limitations<br />
Learn about specific capabilities and limitations of the use of NPIV with <strong>ESXi</strong>.<br />
<strong>ESXi</strong> with NPIV supports the following items:<br />
n NPIV supports vMotion. When you use vMotion to migrate a virtual machine it retains the assigned<br />
WWN.<br />
If you migrate an NPIV-enabled virtual machine to a host that does not support NPIV, VMkernel reverts<br />
to using a physical HBA to route the I/O.<br />
n If your FC SAN environment supports concurrent I/O on the disks from an active-active array, the<br />
concurrent I/O to two different NPIV ports is also supported.<br />
When you use <strong>ESXi</strong> with NPIV, the following limitations apply:<br />
n Because the NPIV technology is an extension to the FC protocol, it requires an FC switch and does not<br />
work on the direct attached FC disks.<br />
n When you clone a virtual machine or template with a WWN assigned to it, the clones do not retain the<br />
WWN.<br />
n NPIV does not support <strong>Storage</strong> vMotion.<br />
n Disabling and then re-enabling the NPIV capability on an FC switch while virtual machines are running<br />
can cause an FC link to fail and I/O to stop.<br />
40 <strong>VMware</strong>, Inc.