Logical Partitioning (LPAR) - An Overview
The objective of logical partitioning (LPAR) is to provide users with
the ability to divide a single managed system into several independent systems, called partitions. Logical partitions are user-defined system resource divisions. Users determine the number of processors, memory, and I/O that a logical partition can have when active. You can install an operating system on each partition and use each one as you would a separate physical system.
Benefits of Logical Partitioning
Partitioning provides greater flexibility when deploying multiple workloads on servers,
providing better management, improved availability, and more efficient use of resources. Some specific benefits of logical partitioning include:
- Consolidate Servers: A server with sufficient processing capacity that is capable of
being partitioned can address the need for server consolidation by logically
subdividing the server into a number of separate, smaller systems. In this way,
application-isolation needs can be met in a consolidated environment, with the
additional benefits of reduced floor space, a single point of management, and easier
redistribution of resources as workloads change.
- Merge Production and Test Environments: Partitioning enables separate partitions
to be allocated for production and test systems, eliminating the need to purchase
additional hardware and software. When testing has been completed, the resources
allocated to the test partition can be returned to the production partition or elsewhere
as required. As new projects are developed, they can be built and tested on the
same hardware on which they will eventually be deployed.
- Consolidate Multiple Versions of the Same Operating System: A single system
can have different versions of the operating system installed to accommodate
multiple application requirements. Furthermore, a partition can be created to test
applications under new versions of the operating system prior to upgrading the
production environments. Instead of having a separate server for this function, a
minimum set of resources can be temporarily used to create a new partition where
the tests are performed. When the partition is no longer needed, its resources can be
incorporated back into the other partitions.
- Consolidate Applications Requiring Different Time Zone Settings: Partitioning
enables multiple regional workloads to be consolidated onto a single server. The
different workloads can run in different partitions, with different operating systems, as
well as with different time and date settings. For example, workloads for operations
bbased in San Francisco and New York can run in different partitions on a single
server. The evening batch workload, maintenance, or upgrade for the New York
operation does not affect those of the San Francisco operation.