Advanced POWER Virtualization on IBM System p5 - Previous ...

The key benefit of implementing partitioning in the hardware allows any operating
system to run on <strong>POWER</strong>5 technology with little or no changes. Optionally, for
optimal performance, the operating system can be enhanced to exploit shared
processor pools more in-depth, for example, by voluntarily relinquishing CPU
cycles to the hardware when they are not needed. AIX 5L Version 5.3 is the first
version of AIX 5L that includes such enhancements.
Micro-Partitioning allows multiple partitions to share one physical processor.
Logical partitions using Micro-Partitioning technology are referred to as shared
processor partitions.
A partition may be defined with a processor capacity as small as .10 processor
units. This represents 1/10 of a physical processor. Each processor can be
shared by up to 10 shared processor partitions. The shared processor partitions
are dispatched and time-sliced on the physical processors under control of the
<strong>POWER</strong> Hypervisor.
Micro-Partitioning is supported across the entire <strong>POWER</strong>5 product line from
entry level to the high-end systems. Table 2-2 shows the maximum number of
logical partitions and shared processor partitions supported on the different
models.
Table 2-2 Micro-Partitioning overview
Server/Model
505/510/
520/52A
550 55A 570 575 590 595
Processors 2 4 8 16 16 32 64
Dedicated processor 2 4 8 16 16 32 64
partitions
Shared processor
partitions
20 40 80 160 160 254 254
It is important to point out that the maximums stated are supported by the
hardware, but the practical limits based on production workload demands may be
significantly lower.
Shared processor partitions still need dedicated memory, but the partitions I/O
requirements can be supported through virtual Ethernet and virtual SCSI.
Utilizing all virtualization features, up to 254 shared processor partitions is
currently supported.
The shared processor partitions are created and managed by the HMC. When
you start creating a partition, you have to choose between a shared processor
partition and a dedicated processor partition.
Chapter 2. <strong>Virtualization</strong> technologies on System p servers 33