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System Management Guide: Operating System and Devices

Specifying WLM Properties

The system administrator can specify the properties for the WLM subsystem by using either the Web-based System Manager graphical user interface, SMIT ASCII-oriented interface, the WLM command line interface, or by creating flat ASCII files. The Web-based System Manager and SMIT interfaces use the WLM commands to record the information in the same flat ASCII files. These files are named as follows:

classes Class definitions
description Configuration description text
limits Class limits
shares Class target shares
rules Class assignment rules

These files are called the WLM property files. A set of WLM property files defines a WLM configuration. You can create multiple sets of property files, defining different configurations of workload management. These configurations are located in subdirectories of /etc/wlm. The WLM property files describing the superclasses of the Config configuration are the file's classes, description, limits, shares and rules in /etc/wlm/Config. Then, the property file's describing the subclasses of the superclass Super of this configuration are the file's classes, limits, shares and rules in directory /etc/wlm/Config/Super. Only the root user can star or stop WLM, or switch from one configuration to another.

The command to submit the WLM property files, wlmcntrl, and the other WLM commands allow users to specify an alternate directory name for the WLM properties files. This allows you to change the WLM properties without altering the default WLM property files.

A symbolic link, /etc/wlm/current, points to the directory containing the current configuration files. Update this link with the wlmcntrl command when you start WLM with a specified set of configuration files. The sample configuration files shipped with the operating system are in /etc/wlm/standard.

Defining Classes

In order to fully define a class, you must give it a name. You can also specify the values of the class attributes for which you want a value different from the system or user defined default. These attributes are the tier number, inheritance, and the name of the user or group of users authorized to manually assign processes to the class. In addition, when defining a superclass you can specify the name of the user or group of users authorized to perform the administration of the subclasses for this superclass. Next, you define the CPU, physical memory, disk I/O shares and resource limits, followed by the class assignment rules for this class. These rules are used by WLM to automatically assign processes to the class at exec time. The system administrator must provide a set of rules used to assign processes to one of the superclasses. For each superclass with user defined subclasses, either the system administrator or a superclass administrator authorized by the system administrator must provide rules to assign processes to one of the subclasses of the superclass.

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