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Specify custom upper and lower metric bounds

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Specify custom upper and lower metric bounds

Use the Bounds Settings wizard to override learned control bounds by specifying custom upper and lower bounds for an Operational Intelligence metric.

Before you begin

Role required: evt_mgmt_admin

About this task

Operational Intelligence calculates upper and lower control bounds for metrics using statistical models learned from historical metric data. Upper and lower bounds are then used in the analysis for detecting anomalous CIs or resources, affecting anomaly scores. Based on historical data, some CIs, resources, or metrics might have values that you specifically want or do not want to be notified about, despite the calculated ranges. For example, trying to meet an SLA without allowing a metric to exceed or be below a certain value for too long without being notified. When concrete upper or lower bound values are known for a metric, you can configure that metric with custom bounds to override the calculated bounds. For example, a CPU metric which does not exceed 85%.

Use the Bounds Settings wizard to specify custom static bounds or ranges of bounds, and to preview anomaly analysis of actual data based on the custom settings. The metric class and the configuration setting rule that custom bounds must be associated with, are both automatically generated by the Bounds Settings wizard.

In the Bounds Settings wizard, you can choose one of the following options for custom control bounds:
Static upper and lower bounds
Custom static upper and lower bound values are used as the control bounds in effect, completely overriding the learned values for upper and lower bounds for the metric. The median of the metric data must be within the specified static bounds range, otherwise the static bounds are not applied.
Ranges for upper and lower bounds
Custom upper and lower bounds, each expressed as a range of values. The bounds in effect are a combination of the custom minimum and maximum values that define the bound range, and the learned upper and lower bounds:
  • If a learned bound value for a point in time is within the custom range of upper or lower bound, then the learned bound value is in effect.
  • If a learned bound value for a point in time is outside the custom range, then the Max or the Min values of the custom range are in effect respectively. If the learned value exceeds the custom range, then the custom Max value is in effect, and if below then the Min custom value is in effect.

When a metric value is outside a control bound, the deviation from the control bound is normalized by a width value that the system calculates from data. Lower and upper width values determine how much a metric value needs to exceed the control bounds to be anomalous. Changing a width for the control bounds affects the speed of reaching a high anomaly score and being notified about the anomaly. In addition to setting custom control bounds, you can override width values by specifying custom deviation and time values that the system uses to calculate custom widths values.

The system stores custom control bounds and custom widths for a metric in a metric class. Custom values in a metric class override the learned bounds and widths for the metric, and are then used in subsequent anomaly analysis.

Procedure

  1. Navigate to Operational Intelligence > Configure > Bounds Settings.
  2. In the Bounds Settings list view, click Add to open the Bounds Settings wizard.
  3. On the Select Scope tab, configure the following settings and then click Next.
    Field Description
    Source Metric Type(s)

    Source metric type that this bounds setting applies to.

    Select an item from the drop-down list, and then click the Add Source Metric Type icon (+) to add the selected item to Selected Source Metric Types.

    Scope

    Scope of CIs or resources that this bounds setting applies to.

    You can set the scope to All CIs, Specific CI or class, or Specific Resource or Resource class. Depending on the setting, you can then further filter the scope.

  4. On the Apply Bounds Settings tab, configure the following settings and then click Next.
    Field Description
    Bounds setting name Unique name for this bounds setting.
    Bounds type Method for specifying the custom static bounds:
    • Set static upper and lower bounds
    • Set ranges for upper and lower bounds
    Show advanced settings
    The following fields appear:
    • If lower bound is and And metric value is below lower bound by
    • If upper bound is and And metric value is above upper bound by
    • Send critical alert after duration (min.)

    Specify the deviation for anomalous values (in absolute values), and the duration for sending an anomaly alert. These values are used internally to calculate the width value for the metric.

    Note:

    If the metric class specified for the bounds setting, is configured with width override values from an upgraded release, you cannot set advanced settings. To set advanced settings, accept the notification that appears, agreeing that those width override values be deleted.

    See Operational Intelligence release notes for more details.

    Lower bound Static lower bound value that replaces the learned lower bound for the metric. Applies to the Static upper and lower bounds setting.
    Upper bound Static upper bound value that overrides the learned upper bound for the metric. Applies to the Static upper and lower bounds setting.

    Value must be greater than Lower Bound.

    Lower Bound Range Min and Max of the custom lower bound range. Applies to the Set ranges for upper and lower bounds setting.
    Upper Bound Range Min and Max of the custom upper bound range Applies to the Set ranges for upper and lower bounds setting.
  5. On the Preview and Confirm tab:
    1. Select a Source Metric Type and optionally a Metric Type for the preview.
    2. Optionally, enter a CI Name and a Resource Name that you want to include in the preview. If you specify a CI or a resource, it must be within the scope that was previously specified.
    3. Click Preview to perform anomaly detection for the specified metric and CI, using the newly specified custom bounds.
    4. Examine the preview results and if the results are as expected, click Finish. Otherwise, go back to the previous Apply Bounds Settings tab, adjust settings, and then preview again.
      The preview results are a stripped-down version of anomaly model testing. For more details about the results, and changing chart settings, see Anomaly model testing.
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