I/O Groups For ports within an I/O group, you can enable virtualization of Fibre Channel ports that are  used for host I/O operations. With N_Port ID virtualization (NPIV), the Fibre Channel port  consists of both a physical port and a virtual port. When port virtualization is enabled, ports  do not come up until they are ready to handle I/O, which improves host behavior around node  unpends. In addition, path failures due to an offline node are masked from hosts. The target port mode on the I/O group indicates the current state of port virtualization: The system can be in the transitional state for an indefinite period while the system  configuration is changed. However, system performance can be affected because the  number of paths from the system to the host doubled. To avoid increasing the number of  paths substantially, use zoning or other means to temporarily remove some of the paths  until the state of the target port mode is enabled. The port virtualization settings of I/O groups are available by clicking  Settings  System I/O Groups , as shown in Figure 5-69. Figure 5-69 I/O Groups port virtualization Chapter 5. Graphical user interface  197 GLYPH<SM590000> Enabled:  The I/O group contains virtual ports that are available to use. GLYPH<SM590000> Disabled:  The I/O group does not contain any virtualized ports. GLYPH<SM590000> Transitional:  The I/O group contains both physical Fibre Channel and virtual ports that  are currently being used. You cannot change the target port mode directly from enabled to  disabled states, or vice versa. The target port mode must be in transitional state before it  can be changed to either disabled or enabled states. 