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, or by creating flat ASCII files. The Web-based System Manager and SMIT interfaces record the information in the same flat ASCII files. These files are named as follows:
| classes | Class definitions |
| description | Class 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. Only the root user can load WLM property files.
The command to submit the WLM property file, 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 AIX are in /etc/wlm/standard.
In order to fully define a class, you must give it a name. You can also specify its tier value, however, this is optional. If a tier value is not specified, the default value is zero. Next, you define the CPU and physical memory resource limits, then the class assignment rules for this class. These rules are used by WLM to automatically assign processes to this class at exec() time.
Class names can contain up to 16 upper and lowercase alphanumeric characters and can include the underscore character. The only names that have a special meaning to the system are Default and System. The maximum total number of classes you can define is 29.
Default is a special class that is always defined. All processes that are not automatically assigned to another class are assigned to the Default class. You cannot specify classification rules for this class. Resource limits can be placed on this class as they can for any other class. The default is to have no resource limits applied.
System is another special class that is always defined. This class gets all privileged processes (root processes) that are not automatically assigned to another class. Resource limits can be placed on this class as they can for any other class. The default is for this class to have a memory minimum limit of 1%.