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Use Conditions to Adjust Resource Policies

  • Article

Applies To: Windows Server 2008

Windows System Resource Manager can automatically switch to a different managing policy when one of six preconfigured events occurs. In addition, when one of these events occurs, you can configure the conditional policy to evaluate additional system states and switch to another policy if one of the states is found to be true.

Note

States that are configured as part of a conditional policy are only evaluated, and their associated managing policies are only implemented, if the event that they are part of occurs first.

Six events are supported by Windows System Resource Manager. In the default installation, no policy changes occur when one of the events occurs.

Events that trigger conditional policy changes

Only one conditional policy can be configured for each event category. Each time an event occurs, any associated policy changes are implemented.

A special condition category Any is also installed by default. The Any condition category is only evaluated if no conditional policy exists for an event type.

Specific events that trigger conditional policy changes include:

  • Hot addition of a processor or processors

  • Hot addition of memory (RAM)

  • A Cluster service node comes online

  • A Cluster service node goes offline

  • A Cluster service resource group comes online

  • A Cluster service resource group goes offline

States that can be evaluated when an event occurs

After an event occurs, any states configured as part of the conditional policy for the event are evaluated. In order for Windows System Resource Manager to take action in response to an event, the event's conditional policy must contain at least one state to be evaluated.

States can be configured as single clauses, or as groups in which one or more clauses must be true in order for the state to be evaluated as true.

Clauses in a state can include:

  • Whether the number of processors is greater than, less than, or equal to a specified quantity

  • Whether the amount of memory is greater than, less than, or equal to a specified quantity

  • Whether a Cluster service node is online or offline

  • Whether a Cluster service resource group is online or offline

How conditional policies are applied

Conditional policies change the managing state according to the following process:

  1. An event occurs.

  2. Windows System Resource Manager looks for an existing conditional policy associated with the event.

    • If a conditional policy exists, Windows System Resource Manager proceeds from step 3 using the states and default policy for that conditional policy.

    • If a conditional policy does not exist, Windows System Resource Manager proceeds from step 3 using the states and default policy configured for the Any condition category.

  3. Windows System Resource Manager looks for states to be evaluated when the event occurs.

    • If there are no states configured to be evaluated as part of the conditional policy, no action is taken.

    • If there are states configured, the states are evaluated in order until one of the states is found to be true, and the action associated with the first true state is taken.

    • If no configured state is true, the default policy for the event (or for the Any condition category) is applied.

Editing conditional policies

Configuring the default policy

When an event occurs, Windows System Resource Manager will evaluate the states associated with the event, and if no state is true, the default policy associated with the event will be applied.

To configure the default policy associated with an event

  1. Open Windows System Resource Manager.

  2. In the navigation tree, right-click Conditions, and then click Add/Edit Conditional Policies.

  3. In the Add or Edit Conditional Policy dialog box, click the name of the event you want to configure, and then click Edit. The Conditional Policy Properties dialog box will open.

  4. Click a resource allocation policy name in the Choose default policy here drop-down list.

Note

The default policy is only applied if no state configured as part of the conditional policy is true.

Configuring additional states

In order for Windows System Resource Manager to take action when an event occurs, you must configure at least one state to be evaluated in the conditional policy for the event.

States are evaluated in the order in which they are listed from top to bottom. Once a state is found to be true, Windows System Resource Manager will switch the managing policy to the policy associated with that state, and no other states will be evaluated.

  • To change the order in which states are evaluated, in States, click the state you want to move, and then click the up or down arrows to move it.

  • To exclude a state from evaluation, de-select the check box next to the state. Note that if no states are selected for evaluation, no action will be taken when the event occurs.

To configure additional states to be evaluated when an event occurs

  1. In the Add or Edit Conditional Policy dialog box, click the name of the event you want to configure, and then click Edit. The Conditional Policy Properties dialog box will open.

  2. Click in an empty row in States to access the details configuration and create one or more clauses.

Note

You cannot configure the name of a state that has no clauses. The name column will be populated with information from the clauses you define.

  1. In Details for the selected state above, click in an empty cell in the Category column to select a category from the drop-down list.

    • If you selected Processor or Memory, click in the Operator column to choose an operator, and then click in the Quantity column to type a number of processors or a memory quantity (in MB).

    • If you selected MSCS, click to select a value from the Object Name drop-down list, type the name of the node or resource group in the Object Name cell, and then click in the State column to select a state from the drop-down list.

  2. When you are finished creating state clauses, in States, click the Policy Name column in the row for the state you just created. In the drop-down list, choose a policy to apply when the state is true.

Grouping state clauses

You can group state clauses so that one or more clauses must be true in order for the group to be evaluated true.

  • AND and OR operators have equal precedence.

  • Expressions are evaluated from left to right.

  • Grouped clauses are evaluated first. In the case of a nested group, the deepest nested group is evaluated first.

To combine state clauses to be evaluated as a group

  1. In the Add or Edit Conditional Policy dialog box, click the name of the event you want to configure, and then click Edit. The Conditional Policy Properties dialog box will open.

  2. In States, click an empty cell to create a new state, or click an existing state row.

  3. In Details for the selected state above, add multiple states that you want to combine as a single clause to be evaluated true or false.

  4. In Details for the selected state above, click the first row you want to combine with another row, and then press SHIFT+click at the same time to select rows to combine.

Note

You can only group rows that are consecutive. Nested groups are supported.

  1. Right-click the highlighted rows, and then click Add Group.

Additional considerations

  • To open Windows System Resource Manager, click Start, point to Administrative Tools, and then click Windows System Resource Manager. In the Connect to Computer dialog box, select This computer, and then click Connect. Microsoft Management Console will start with the Windows System Resource Manager (Local) snap-in open.

  • Conditional policies assume that processors and memory cannot be removed while a computer is in service.

Additional references