Metric evaluation is the assessment of metric data. Metric evaluation lets you compare the metric data to a pre-determined value or range or the value of another metric. If the metric data meets the specified conditions of the rule, then the rule is triggered. Triggered rules can perform actions such as raising an alert in the Event Console.
Rules are classified into different rule types. Some rule types use metric evaluation and some rule types do not. If a rule type supports metric evaluation, the rule can evaluate the metric data that it gathers. If a rule type does not support metric evaluation, the rule gathers the metric data but does not evaluate it.
Metric evaluation supports the following metric types:
You can add multiple sequences of metric evaluations to a rule using the IF, AND, and OR operators. The operators determine the logic for the evaluations. The operators let you create more complex rules and allow for more accurate evaluations. With only one metric evaluation, your rule may be more generic - the operators allow for a more focused rule.
The evaluation methods that you specify are processed linearly - the functions that you specify evaluate one after the other. For example, if you set up a rule that stated that:
IF metric evaluation x.
AND metric evaluation y.
OR metric evaluation z.
The evaluation first checks to see if both metric evaluation x and metric evaluation y are true. If those are both true then the rule is triggered. If not, then the logic moves on to check if metric evaluation z is true. If metric evaluation z is true then the rule is triggered. This set of evaluation methods does not check first to see if: metric evaluation x is true, and then check to see if metric evaluation y is true or metric evaluation z is true. The "and" applies to the first step in the evaluation method.
If multiple evaluations are used, the If operator is only available for the first evaluation.
Imported Document ID: HOWTO64020
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