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Mt Xia:
Business Continuity/Disaster Recovery Methodologies
WLM AIX 5 |
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Workload Manager for AIX 5L StandardsThis document describes the Workload Manager implementation standards on AIX version 5 machines only.For WLM implementation on AIX version 4.3.3.0 systems, see the AIX 4.3.3.0 WLM standards document.The workload manager (WLM) shall be implemented on all AIX systems. On most systems WLM will be running in "passive" mode, which does not limit resources. In Mt Xia's environment, only a few selected systems will have WLM implemented in "active" mode to control and regulate resources. If there is any question as to whether WLM should be implemented in "active" or "passive" mode, default to "passive". The WLM provides a mechanism to classify and segment resources by process, user, group, etc. The classification scheme must be constructed by the AIX system administrator. This WLM classification scheme in the Mt Xia environment is based on the concept of the Resource Group. Each Resource Group will be represented in WLM as a class. Multiple instances of an application within a single resource group shall be represented in WLM as subclasses. In order to configure WLM, the system administrator must first define the resource groups names. Once the resource group names have been defined, then a WLM class must be defined using the resource group name as the WLM class name. To define a new WLM class using smitty, start smitty using the "wlm" fastpath. Select "Add a class" to define a new WLM class. Enter the resource group name as the WLM class name, and provide a description of this WLM class. The Tier level will normally be 0 (zero) unless there is a specific reason to change this. The "Resource Set Inheritance" value will normally be set to "Yes". The user and group values will be dependent upon the nature of the resource group. It may be desirable to specify a non-root user and group that is permitted to administer the WLM class and/or assign processes to the class. This will have to be determined on a resource group by resource group basis. If this information is unknown, default to "root" for the user values and "system" for the group values. Class rules are used to determine which processes are assigned to which WLM classes and the order of the rules is significant. The first rule that matches is used to determine the WLM class assignment, so the class rules should be ordered from highly specific to less specific. To define WLM class rules using smitty, start smitty using the "wlm" fastpath. Select "Class assignment rules" to define a new WLM class. Select "Class assignment rules" to define a new WLM class rule. In the following example, a rule is defined to assign all processes owned by oracle or the group dba to the the WLM class "egapdtu1". Again the order of the rules is important. The rules should be ranked in order of highly specific, starting at 1, to less specific. To define a new WLM subclass using smitty, start smitty using the "wlm" fastpath. Select "Add a class" to define a new WLM subclass. When defining a subclass, again enter the resource group name, followed by a period (.) followed by the name of the subclass to create. The Tier level will normally be 1 (one) for a subclass, unless there is a specific reason to change this. The "Resource Set Inheritance" value will normally be set to "Yes". The user and group values will be dependent upon the nature of the resource group. It may be desirable to specify a non-root user and group that is permitted to administer the WLM class and/or assign processes to the class. This will have to be determined on a resource group by resource group basis. If this information is unknown, default to "root" for the user values and "system" for the group values. To define a class rule for a subclass requires an additional step. First select a set of WLM subclasses to work on, then define the rule. To define a rule for a WLM subclass using smitty, start smitty using the "wlm" fastpath. Select "Work on a set of Subclasses" to select the subclass for which to define a rule. Select the WLM class that contains the subclass for which the rule will be defined, press enter, then return to the main WLM menu. Select "Class assignment rules" to define a new WLM subclass rule. Select "Class assignment rules" to define a new WLM subclass rule. In the following example, a rule is defined to assign all processes owned by oracle or the group dba to the the WLM subclass "egapdtu1.oracleex511". Again the order of the rules is important. The rules should be ranked in order of highly specific, starting at 1, to less specific. After all classes, subclasses, and rules have been defined, start WLM. Select "Work on a set of Subclasses" to select the subclass for which to define a rule. Select "Start Workload Manager" For the options on this page, select the "current" configuration set, choose the "Passive" management mode, and choose "Both" for the start option. Any subsequent changes to the WLM configuration will require that WLM be stopped and restarted in order for the changes to take effect.
An example WLM configuration of the EGATE Production Database server for Mt Xia follows. The "standard" WLM configuration for this machine contains a single WLM class called "egapdtu1". It is important to recognize that the "standard" WLM configuration will be different for every machine. The term "standard" is used in reference to the local machine, this is not enterprise wide terminology used here.
The class rules associated with this "standard" configuration assign any processes owned by "oracle" or by the group "dba" to the WLM class "egapdtu1". All processes owned by "root" are assigned to the class "System", and all other processes are assigned to the class "Default".
Multiple subclasses are defined for the class "egapdtu1". These subclasses are intended to segment the processes by oracle instance. The definition of subclasses will be customized for each individual resource group.
The rules associated with each subclass of the class "egapdtu1" associate all processes owned by "oracle" or the group "dba" to the subclass. In this instance the processes are not automatically assigned to subclasses by WLM, instead they are assigned by the oracle startup script.
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For information regarding this page, contact
Dana French ( dfrench@mtxia.com )
Copyright 2008 by Mt Xia Inc, All Rights Reserved