Important Concepts

Creating an adaptive threshold is based on the following key concepts:

• Baseline periods

  For the purpose of performance evaluation, a baseline period is a period of time used to characterize the typical behavior of the system. You compare system behavior over the baseline period to that observed at some other time.

  There are two types of baseline periods:

• Moving window baseline periods: Moving window baselines are defined as some number of days prior to the current date. This "window" of days forms a rolling interval that moves with the current time. The number of days that can be used to define moving window baseline in Enterprise Manager are:

  • 7 days

  • 14 days

  • 21 days

  • 30 days

    Example: Suppose you have specified trailing 7 days as a time period while creating moving window baseline. In this situation, the most recent 7-day period becomes the baseline period for all metric observations and comparisons today. Tomorrow, this reference period drops the oldest day and picks up today.

    Moving window baselines allow you to compare current metric values with recently observed history, thus allowing the baseline to incorporate changes to the system over time. Moving window baselines are suitable for systems with predictable workload cycles.

  Note:

  Enterprise Manager computes moving window statistics every day rather than sampling.