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System Management Guide: Operating System and Devices

Chapter 12. Workload Manager

Workload Manager (WLM) is designed to give system administrators more control over how the scheduler and the virtual memory manager (VMM) allocate resources to processes. This can be used to prevent different classes of jobs from interfering with each other and to allocate resources based on the requirements of different groups of users.

WLM gives you the ability to create different classes of service for jobs, and specify attributes for those classes. These attributes specify minimum, optimum and maximum amounts of CPU, physical memory, and disk I/O bandwidth to be allocated to a class. The system administrator also defines class assignment rules used by WLM to assign jobs automatically to classes. These rules are based upon attributes of a process, such as the name of the user or group, the pathname of the applications executed, the type of process (that is, 32 bit or 64 bit), and the application tag.

WLM also provides isolation between user communities with very different system behaviors. This can prevent effective starvation of workloads with certain behaviors (for example, interactive or low CPU usage jobs) by workloads with other behaviors (for example, batch or high memory usage jobs).

Also, WLM ties into the accounting subsystem (see Accounting Overview in the AIX 5L Version 5.1 System Management Concepts: Operating System and Devices) allowing users to do resource usage accounting per WLM class in addition to the standard accounting per user or group.

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