The baseline is the expected normal operating range for a metric or attribute of a monitor.
The baseline is calculated by collecting the values for a monitor's attributes and metrics over a specified time period and establishing a low baseline value (consisting of the 10th percentile of all the values for a given time period) and a high baseline value (consisting of the 90th percentile of all the values for a given time period), taking a weighted average of these values over time. A higher weight is given to the latest data being factored into the baseline average. The accuracy of the baseline improves over time.
To track the anomalies in behavior for different attribute types, different patterns are required. For example, for attributes that change frequently, a pattern captured at hourly intervals may be best. Hourly interval ranges represent a smaller number of data points and have a tighter range, which is best suited for capturing frequent changes.
Infrastructure Management captures the following baseline patterns:
Seasonal baseline - Baseline is calculated separately for pre-determined days when your business experiences out-of-the-ordinary workloads or other special behavior. If factored into the baseline, it artificially raises or lowers the baseline, causing unnecessary abnormalities.
Baseline administration provides a better control over baseline calculations. For example, you can specify freeze points to discard values corresponding to specific periods. Similarly, if the baseline is not correct, it can be easily reset. You can also create baselines for special or seasonal dates.
For baselines to be generated for an attribute, that attribute must have an active abnormality threshold. An active abnormality threshold means that the threshold exists and is not suppressed.
Additionally, if the Key Performance Indicator (KPI) mode is active, only those attributes that have an active abnormality threshold and are also KPI attributes have baselines generated for them.
Absolute thresholds (with "outside baseline") or signature thresholds do not satisfy these requirements.