IBM DS8000 manual Software and hardware fault isolation, Dynamic logical partitioning, Virtual I/O

				Logical Partition
Logical			Logical Partition 1			Logical Partition 2
Partition 0
Processor		Processor		Processor	Processor	Processor		Processor
Cache		Cache		Cache	Cache	Cache		Cache
I/O	I/O	I/O	I/O	I/O I/O I/O I/O I/O		I/O	I/O	I/O
				Memory
		hardware management console

Figure 3-1 Logical partition

Software and hardware fault isolation

Because a partition hosts an independent operating system image, there is strong software isolation. This means that a job or software crash in one partition will not effect the resources in another partition.

Dynamic logical partitioning

Starting from AIX 5L™ Version 5.2, IBM supports dynamic logical partitioning (also known as DLPAR) in partitions on several logical partitioning capable IBM pSeries server models.

The dynamic logical partitioning function allows resources, such as CPUs, memory, and I/O slots, to be added to or removed from a partition, as well as allowing the resources to be moved between two partitions, without an operating system reboot (on the fly).

Micro-Partitioning™

With AIX 5.3, partitioning capabilities are enhanced to include sub-processor partitioning, or Micro-Partitioning. With Micro-Partitioning it is possible to allocate less than a full physical processor to a logical partition.

The benefit of Micro-Partitioning is that it allows increased overall utilization of system resources by automatically applying only the required amount of processor resource needed by each partition.

Virtual I/O

On POWER5 servers, I/O resources (disks and adapters) can be shared through Virtual I/O. Virtual I/O provides the ability to dedicate I/O adapters and devices to a virtual server,

46DS8000 Series: Concepts and Architecture