Virtual Fibre Channel

With N_Port ID Virtualization (NPIV), you can configure the managed system so that multiple logical partitions can access independent physical storage through the same physical Fibre Channel adapter.

To access physical storage in a typical storage area network (SAN) that uses Fibre Channel, the physical storage is mapped to logical units (LUNs) and the LUNs are mapped to the ports of physical Fibre Channel adapters. Each physical port on each physical Fibre Channel adapter is identified using one worldwide port name (WWPN).

NPIV is a standard technology for Fibre Channel networks that enables you to connect multiple logical partitions to one physical port of a physical Fibre Channel adapter. Each logical partition is identified by a unique WWPN, which means that you can connect each logical partition to independent physical storage on a SAN.

To enable NPIV on the managed system, you must create a Virtual I/O Server logical partition (version 2.1, or later) that provides virtual resources to client logical partitions. You assign the physical Fibre Channel adapters (that support NPIV) to the Virtual I/O Server logical partition. Then, you can connect virtual Fibre Channel adapters on the client logical partitions to virtual Fibre Channel adapters on the Virtual I/O Server logical partition. A virtual Fibre Channel adapter is a virtual adapter that provides client logical partitions with a Fibre Channel connection to a storage area network through the Virtual I/O Server logical partition. The Virtual I/O Server logical partition provides the connection between the virtual Fibre Channel adapters on the Virtual I/O Server logical partition and the physical Fibre Channel adapters on the managed system.

The following figure shows a managed system configured to use NPIV.

A managed system configured to use NPIV

The figure shows the following connections:

  • A storage area network (SAN) connects three units of physical storage to a physical Fibre Channel adapter that is located on the managed system. The physical Fibre Channel adapter is assigned to the Virtual I/O Server and supports NPIV.
  • The physical Fibre Channel adapter connects to three virtual Fibre Channel adapters on the Virtual I/O Server. All three virtual Fibre Channel adapters on the Virtual I/O Server connect to the same physical port on the physical Fibre Channel adapter.
  • Each virtual Fibre Channel adapter on the Virtual I/O Server connects to one virtual Fibre Channel adapter on a client logical partition. Each virtual Fibre Channel adapter on each client logical partition receives a pair of unique WWPNs. The client logical partition uses one WWPN to log into the SAN at any given time. The other WWPN is used when you move the client logical partition to another managed system.

Using their unique WWPNs and the virtual Fibre Channel connections to the physical Fibre Channel adapter, the operating systems that run in the client logical partitions discover, instantiate, and manage their physical storage located on the SAN. In the previous figure, Client logical partition 1 accesses Physical storage 1, Client logical partition 2 accesses Physical storage 2, and Client logical partition 3 accesses Physical storage 3. For IBM® i client partitions, the LUNs of the physical storage connected with NPIV require a storage-specific device driver and do not use the generic virtual SCSI device driver. The Virtual I/O Server cannot access and does not emulate the physical storage to which the client logical partitions have access. The Virtual I/O Server provides the client logical partitions with a connection to the physical Fibre Channel adapters on the managed system.

There is always a one-to-one relationship between virtual Fibre Channel adapters on the client logical partitions and the virtual Fibre Channel adapters on the Virtual I/O Server logical partition. That is, each virtual Fibre Channel adapter on a client logical partition must connect to only one virtual Fibre Channel adapter on the Virtual I/O Server logical partition, and each virtual Fibre Channel on the Virtual I/O Server logical partition must connect to only one virtual Fibre Channel adapter on a client logical partition. Mapping of multiple Virtual Fibre Channel adapters of a single client logical partition through multiple virtual server Fibre Channel adapters to the same physical Fibre Channel adapter is not recommended.

Using SAN tools, you can zone and mask LUNs that include WWPNs that are assigned to virtual Fibre Channel adapters on client logical partitions. The SAN uses WWPNs that are assigned to virtual Fibre Channel adapters on client logical partitions the same way it uses WWPNs that are assigned to physical ports.