Virtualization VIO basics

The Virtual I/O Server is part of the IBM System p Advanced Power Virtualization hardware feature. Virtual I/O Server allows sharing of physical resources between LPARs including virtual SCSI and virtual networking. This allows more efficient utilization of physical resources through sharing between LPARs and facilitates server consolidation.

The Virtual I/O Server is software that is located in a logical partition. This software facilitates the sharing of physical I/O resources between AIX® and Linux® client logical partitions within the server. The Virtual I/O Server provides virtual SCSI target and Shared Ethernet Adapter capability to client logical partitions within the system, allowing the client logical partitions to share SCSI devices and Ethernet adapters. The Virtual I/O Server software requires that the logical partition be dedicated solely for its use.
The Virtual I/O Server is available as part of the Advanced POWER™ Virtualization hardware feature.
Using the Virtual I/O Server facilitates the following functions:
-->Sharing of physical resources between logical partitions on the system
-->Creating logical partitions without requiring additional physical I/O resources
-->Creating more logical partitions than there are I/O slots or physical devices available with the ability for partitions to have dedicated I/O, virtual I/O, or both
-->Maximizing use of physical resources on the system
-->Helping to reduce the Storage Area Network (SAN) infrastructure
The Virtual I/O Server supports client logical partitions running the following operating systems:
-->AIX 5.3 or later
-->SUSE Linux Enterprise Server 9 for POWER (or later)
-->Red Hat® Enterprise Linux AS for POWER Version 3 (update 2 or later)
-->Red Hat Enterprise Linux AS for POWER Version 4 (or later)
For the most recent information about devices that are supported on the Virtual I/O Server, to download Virtual I/O Server fixes and updates, and to find additional information about the Virtual I/O Server, see the Virtual I/O Server Web site.
The Virtual I/O Server comprises the following primary components:
-->Virtual SCSI
-->Virtual Networking
-->Integrated Virtualization Manager
The following sections provide a brief overview of each of these components.

Virtual SCSI

Physical adapters with attached disks or optical devices on the Virtual I/O Server logical partition can be shared by one or more client logical partitions. The Virtual I/O Server offers a local storage subsystem that provides standard SCSI-compliant logical unit numbers (LUNs). The Virtual I/O Server can export a pool of heterogeneous physical storage as an homogeneous pool of block storage in the form of SCSI disks.
Unlike typical storage subsystems that are physically located in the SAN, the SCSI devices exported by the Virtual I/O Server are limited to the domain within the server. Although the SCSI LUNs are SCSI compliant, they might not meet the needs of all applications, particularly those that exist in a distributed environment.
The following SCSI peripheral-device types are supported:
-->Disks backed by a logical volume
-->Disks backed by a physical volume
-->Optical devices (DVD-RAM and DVD-ROM)

Virtual networking

Shared Ethernet Adapter allows logical partitions on the virtual local area network (VLAN) to share access to a physical Ethernet adapter and to communicate with systems and partitions outside the server. This function enables logical partitions on the internal VLAN to share the VLAN with stand-alone servers.

Integrated Virtualization Manager

The Integrated Virtualization Manager provides a browser-based interface and a command-line interface that you can use to manage IBM® System p5™ and IBM eServer™ pSeries® servers that use the IBM Virtual I/O Server. On the managed system, you can create logical partitions, manage the virtual storage and virtual Ethernet, and view service information related to the server. The Integrated Virtualization Manager is packaged with the Virtual I/O Server, but it is activated and usable only on certain platforms and where no Hardware Management Console (HMC) is present.

Reference: http://santosh-aix.blogspot.com