IBM DS8000 Introduction to logical partitioning, Virtualization Engine technology, Partitions

3.1 Introduction to logical partitioning

Logical partitioning allows the division of a single server into several completely independent virtual servers or partitions.

IBM began work on logical partitioning in the late 1960s, using S/360 mainframe systems with the precursors of VM, specifically CP40. Since then, logical partitioning on IBM mainframes (now called IBM zSeries) has evolved from a predominantly physical partitioning scheme based on hardware boundaries to one that allows for virtual and shared resources with dynamic load balancing. In 1999 IBM implemented LPAR support on the AS/400 (now called IBM iSeries) platform and on pSeries in 2001. In 2000 IBM announced the ability to run the Linux operating system in an LPAR or on top of VM on a zSeries server, to create thousands of Linux instances on a single system.

3.1.1 Virtualization Engine technology

IBM Virtualization Engine is comprised of a suite of system services and technologies that form key elements of IBM’s on demand computing model. It treats resources of individual servers, storage, and networking products as if in a single pool, allowing access and management of resources across an organization more efficiently. Virtualization is a critical component in the on demand operating environment. The system technologies implemented in the POWER5 processor provide a significant advancement in the enablement of functions required for operating in this environment.

LPAR is one component of the POWER5 system technology that is part of the IBM Virtualization Engine.

Using IBM Virtualization Engine technology, selected models of the DS8000 series can be used as a single, large storage system, or can be used as multiple storage systems with logical partitioning (LPAR) capabilities. IBM LPAR technology, which is unique in the storage industry, allows the resources of the storage system to be allocated into separate logical storage system partitions, each of which is totally independent and isolated. Virtualization Engine (VE) delivers the capabilities to simplify the infrastructure by allowing the management of heterogeneous partitions/servers on a single system.

3.1.2 Partitioning concepts

It is appropriate to clarify the terms and definitions by which we classify these mechanisms.

Note: The following sections discuss partitioning concepts in general and not all are applicable to the DS8000.

Partitions

When a multi-processor computer is subdivided into multiple, independent operating system images, those independent operating environments are called partitions. The resources on the system are allocated to specific partitions.

Resources

Resources are defined as a system’s processors, memory, and I/O slots. I/O slots can be populated by different adapters, such as Ethernet, SCSI, Fibre Channel or other device controllers. A disk is allocated to a partition by assigning it the I/O slot that contains the disk’s controller.

44DS8000 Series: Concepts and Architecture