into to VIO

Prior to the introduction of POWER5 systems, it was only possible to create as many separate logical partitions (LPARs) on an IBM system as there were physical processors. Given that the largest IBM eServer pSeries POWER4 server, the p690, had 32 processors, 32 partitions were the most anyone could create. A customer could order a system with enough physical disks and network adapter cards to so that each LPAR would have enough disks to contain operating systems and enough network cards to allow users to communicate with each partition.The Advanced POWER Virtualization™ feature of POWER5 platforms1 makes it possible to allocate fractions of a physical CPU to a POWER5 LPAR. Using virtual CPU's and virtual I/O a user can create many more LPARs on a p5 system than there are CPU's or I/O slots. The Advanced POWER Virtualization feature accounts for this by allowing users to create shared network adapters and virtual SCSI disks. Customers can use these virtual resources to provide disk space and network adapters for each LPAR they create on their POWER5 system(see Figure ).
There are three components of the Advanced POWER Virtualization feature: Micro-Partitioning™, shared Ethernet adapters, and virtual SCSI. In addition, AIX 5L Version5.3 allows users to define virtual Ethernet adapters permitting inter-LPAR communication. This paper provides an overview of how each of these components works and then shows the details of how to set up a simple three-partition system where one partition is a Virtual I/O Server and the other two partitions use virtual Ethernet and virtual SCSI to differing degrees. What follows is a practical guide to help a new POWER5 customer set up simple systems where high availability is not a concern, but becoming familiar with this new technology in a development environment is the primary goal.