Viewing virtual Fibre Channel adapters

The N_Port ID Virtualization (NPIV) is an industry-standard technology that helps you to configure an NPIV capable Fibre Channel adapter with multiple, virtual worldwide port names (WWPNs). This technology is also called as virtual Fibre Channel. Similar to the virtual Small Computer System Interface (SCSI) function (VSCSI), virtual Fibre Channel is a method to securely share a physical Fibre Channel adapter among multiple Virtual I/O Servers.

Virtual SCSI server provides server-based storage virtualization. Storage resources can be aggregated and pooled on the Virtual I/O Server (VIOS). Two unique, virtual, WWPNs starting with the letter c are generated by the Hardware Management Console (HMC) for the virtual Fibre Channel client adapter. After the activation of the client partition, the WWPNs log in to the storage area network (SAN) similar to other WWPNs from a physical port.

From an architectural perspective, the key difference between the virtual Fibre Channel and the virtual SCSI is that the Virtual I/O Server (VIOS) does not act as a SCSI emulator to its client partitions. Instead, it acts as a direct Fibre Channel pass-through for the Fibre Channel protocol I/O traffic through the POWER Hypervisor. The client partitions are presented with full access to the physical SCSI target devices of a SAN disk or tape storage systems. The benefits of the virtual Fibre Channel are that the physical target device characteristics such as vendor or model information remains fully visible to the VIOS. Hence, you need not change the device drivers such as multi-pathing software, middleware such as copy services, or storage management applications that rely on the physical device characteristics.

Consider the following information when you use the virtual Fibre Channel:
  • One virtual Fibre Channel client adapter per physical port per client partition. This strategy helps to avoid a single point of failure.
  • For Fibre Channel (16GB/s or lesser) adapters, maximum of 64 active virtual Fibre Channel client adapters per physical port. The virtual adapters per physical port can reduce because of other VIOS resource constraints.
  • For Fibre Channel (32GB/s) adapters, maximum of 255 virtual Fibre Channel client adapters per physical port. The virtual adapters per physical port can reduce because of other VIOS resource constraints.
  • Maximum of 64 targets per virtual Fibre Channel adapter.
  • 32,000 unique WWPN pairs per system. Removing a virtual Fibre Channel client adapter does not reclaim worldwide port names (WWPNs). You can manually reclaim WWPNs by using the mksyscfg command and chhwres command or by using the virtual_fc_adapters attribute.
For more information about the capabilities of the Fibre Channel adapter, see PCIe3 x8 2-port Fibre Channel (32 Gb/s).
To enable NPIV on the managed system, create the required virtual Fibre Channel adapters and connections as follows:
  • You use the HMC to create virtual Fibre Channel adapters on the VIOS and associate them with virtual Fibre Channel adapters on the client partitions.
  • You use the HMC to create virtual Fibre Channel adapters on each client partition and associate them with virtual Fibre Channel adapters on the VIOS. When you create a virtual Fibre Channel adapter on a client partition, the HMC generates a pair of unique WWPNs for the client virtual Fibre Channel adapter.
  • You connect the virtual Fibre Channel adapters on the VIOS to the physical ports of the physical Fibre Channel adapter by running the vfcmap command on the VIOS CLI.
The HMC generates WWPNs based on the range of names available for use with the prefix in the vital product data on the managed system. You can get the 6-digit prefix when you purchase the managed system. The 6-digit prefix includes 32,000 pairs of WWPNs. When you remove a virtual Fibre Channel adapter from a client partition, the Power hypervisor deletes the WWPNs that are assigned to the virtual Fibre Channel adapter on the client partition. The HMC does not reuse the deleted WWPNs to generate WWPNs for virtual Fibre Channel adapters. If you require more WWPNs, you must obtain an activation code that includes another prefix that has another 32,000 pairs of WWPNs.

To avoid configuring the physical Fibre Channel adapter to be a single point of failure for the connection between the client partition and its physical storage on the SAN, do not connect two virtual Fibre Channel adapters from the same client partition to the same physical Fibre Channel adapter. Instead, connect each virtual Fibre Channel adapter to a different physical Fibre Channel adapter.

On a server that is managed by the HMC, you can dynamically add and remove virtual Fibre Channel adapters to and from the VIOS and from each client partition. You can also view information about the virtual and physical Fibre Channel adapters and the WWPNs by using VIOS commands.

For more information, see NPIV disk validation for Live Partition Migration.