Subscribe to this information
POWER6 information
With virtual adapters, you can connect logical partitions with each other without using physical hardware. Operating systems can display, configure, and use virtual adapters just like they can display, configure, and use physical adapters. Depending on the operating environment used by the logical partition, you can create virtual Ethernet adapters, virtual fibre channel adapters, virtual Small Computer Serial Interface (SCSI) adapters, and virtual serial adapters for a logical partition.
The system administrator uses the following tools to create virtual adapters:
Adapters can be added while the system is running using dynamic logical partitioning. The virtual adapters are recorded in system inventory and management utilities. Converged location codes can be used to correlate operating-system level or partition-level software entities to adapters, such as eth0, CMN21, and en0. Similarly, the Ethernet adapters are visible in the same way as physical Ethernet adapters.
By default, virtual Ethernet Media Access Control (MAC) addresses are created from the locally administered range. Using the default MAC addresses, it is possible that different servers will have virtual Ethernet adapters with the same addresses. This situation can present a problem if multiple, virtual networks are bridged to the same physical network.
If a server logical partition providing I/O for a client logical partition fails, the client logical partition might continue to function, depending on the significance of the hardware it is using. For example, if one logical partition is providing the paging volume for another logical partition, a failure of the logical partition providing that particular resource will be significant to the other logical partition. However, if the shared resource is a tape drive, a failure of the server logical partition providing the resource will have only minimal effects on the client logical partition.
The following table summarizes operating system support for using virtual I/O devices.
| Client operating system | Virtual console | Virtual Ethernet | Virtual fibre channel | Virtual disk | Virtual optical | Virtual tape |
|---|---|---|---|---|---|---|
| AIX® | Yes | Yes | Yes | Yes | Yes, on HMC-managed systems, at least one Virtual I/O Server logical partition must be present | Yes |
| IBM® i | Yes | Yes | Yes | Yes | Yes | Yes |
| Linux | Yes | Yes | Yes | Yes | Yes | Yes |
AIX logical partitions support booting from virtual devices, including disk boot from virtual disk, network boot from virtual Ethernet, and tape boot from virtual tape.
The firmware running in AIX and Linux logical partitions recognizes virtual I/O and can start the logical partition from virtual I/O. An IPL can be done either from the network over virtual Ethernet or from a device such as virtual disk or virtual CD.
The following table summarizes operating system support for providing virtual I/O to logical partitions.
| Server | Virtual optical | Virtual console | Virtual disk | Virtual tape | Virtual fibre channel |
|---|---|---|---|---|---|
| IBM i | Yes | Yes | Yes | Yes | No |
| Linux | Yes | Yes | No | No | No |
| Virtual I/O Server | Yes | Yes | Yes | Yes | Yes |
Virtual I/O Server provides SCSI disk, shared Ethernet, virtual fibre channel, virtual optical, and virtual tape functions to logical partitions that use Virtual I/O Server resources. The Virtual I/O Server also provides a virtual console to AIX and Linux logical partitions.
IBM i provides disk, CD, tape, and console functions to logical partitions that use IBM i resources. IBM i uses standard IBM i network server storage and network server descriptions to provide disk, CD, and tape resources to other logical partitions. An IBM i logical partition cannot simultaneously provide virtual resources to other logical partitions and use virtual resources provided by another IBM i logical partition or by the Virtual I/O Server logical partition.
To configure virtual I/O for the logical partitions on your managed system, you must create virtual I/O adapters on the HMC or Integrated Virtualization Manager. Virtual I/O adapters are usually created when you create your logical partitions. Alternatively, you can add virtual I/O adapters to running logical partitions using dynamic logical partitioning. After you create a virtual I/O adapter, you can then access the operating system used by the logical partition and complete the configuration of the virtual I/O adapter in the operating system software. For Linux partitions, virtual adapters are listed in the device tree. The device tree contains virtual SCSI adapters, not the devices under the adapter.
A logical Host Ethernet Adapter (LHEA) is a special type of virtual adapter. Even though an LHEA is a virtual resource, an LHEA can exist only if a physical Host Ethernet Adapter, or Integrated Virtual Ethernet, provides its resources to the LHEA.
