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Partial selection of CIs in a comparison job

The first task the comparison job performs is to get a list of all the CIs that match the qualification set you applied to the baseline and target source datasets. During the initial loading into memory, the qualified CIs are fetched with only three core attributes: ClassId, InstanceId, and ReconciliationIdentity. Because the loading of the baseline CIs and the target CIs can be done separately, the comparison service creates two separate processing threads to load the CIs.

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Application of qualification sets in a Comparison job

Qualification sets can have zero or more qualifications. If there are no qualifications to be applied to the source dataset, the All Objects option is applied. In this option all CIs specified in the baseline or target are included.

If certain qualifications are defined and are to be applied, the comparison service creates a query that is applied to CMDB. The CMDB API returns a set of CIs matching the criteria in the qualification.

The result is the identification of two sets, Baseline and Target. The baseline and target CIs are stored in memory ordered by ClassID.

Application of related classes option in a Comparison job

In Drift Management you can select a set of CIs based on relationships. This feature is very useful when the selected CIs are logically related to other CIs. For example, you can select computer systems related to a particular business service or select products related to a computer system. The product CIs are only used to filter the computer system CIs. The product CIs do not take part in the comparison.

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The Drift Management Qualification Builder allows arbitrary levels of nesting of related classes. This is an I/O intensive operation, with more levels of nesting resulting in longer execution of the query.

Application of Include and Exclude sets

After the qualified CIs are loaded into memory, the comparison service addresses the Include and Exclude sets.

Included and excluded attributes are uniquely identified by a class-attribute combination.

The excluded attributes are used to ignore attributes, thus making the comparison quicker and the Drift Report more relevant. For example, if you are comparing a set of servers against a golden server, you would likely exclude the hostname attribute because it is different from the golden server.

The included attributes identify the attributes to be included in the comparison and the conditions that define a drift. The conditions are designated by the comparison operator and the value entered for each included attribute. With included attributes, you can override the default comparison of equality (==) with other comparisons, such as Less than (LT) and Greater than(GT). In addition, you can override the baseline attribute value with your own value against which you want to compare the target attribute.


 

Tip: For faster searching, add an asterisk to the end of your partial query. Example: cert*

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