Using the Thresholds in the Forecast Performance Percentage Value Reports

Using the Thresholds in the Forecast Performance Percentage Value Reports

The Capacity Reports Management Pack contains a set of reports that give you a powerful forecasting tool for your Operations Manager environment. This blog focuses on the “Forecast Performance Percentage Value Report” reports.

Besides providing forecasted capacity values, the Forecast Performance Percentage Value Reports allow you to identify thresholds in time to proactively respond to the forecasted capacity issue and resolve it before it causes downtime or becomes an issue.

Consider the graph above. The graph shows a steady decline in free disk space (of a particular storage device) over time. The X- Axis shows the date and the Y-Axis shows the percent of free disk space expressed in a percentage. The blue line represents the actual data in the SCOM data warehouse on the free disk space (of a particular storage device). The red-dotted line represents the forecast line (or trend line) for the free disk space data points. When looking at the forecast line, we can see that the trend for free disk space is downwards towards 0%. This would mean that (at point T3 in the graph) the disk would be completely out of free space. Now, as we know, being out of free disk space only means bad things and potentially angry customers or users. Ideally we would like to know well in advance that we are going to run out of free disk space so that we can proactively take action such as cleaning up the disk, or extending the disk.

The “Forecast Performance Percentage Value Report” reports are specifically designed to help you avoid a situation where you would unexpectedly end up at point T3 in the graph, where you have 0% free disk space left. By letting you set thresholds, the report allows you to receive warnings on approaching capacity issues.

When we examine the configurable parameters in the “Forecast Performance Percentage Value Report – displays all capacity objects” report, there are two parameters that can be set in order to receive a warning before the disk is at capacity (T3). The two parameters that can be set are:

  • Number of days for Warning Level
  • Number of days for Critical Level

The “Number of days for Warning Level” corresponds with point T1 in the Free Disk Space graph. When we set the “Number of days for Warning Level” threshold, it will cause the report to show a warning when this threshold is breached as shown in the image below. In this example, the threshold is set to 150 days. This is the distance in days between T1 and T3 on the graph.

The “Number of days for Critical Level” corresponds with point T2 in the Free Disk Space graph. When we set the “Number of days for Critical Level” threshold, it will cause the report to show a critical state when this threshold is breached, as shown in the image below. In this example the threshold is set to 100 days. This is the distance in days between T2 and T3 in the graph.

You might also notice that the “Today” point is still to the left of T1 and outside of the area between T1 and T3. If today is 1-Jan-2016 and T3 is 10-June-2016, the number of days between Today and T3 is 165. Thus, the number of days until capacity (T3) is reached is 165. This means that in this case, “Today” is outside of both the warning (T1) and critical (T2) thresholds set, and therefore displaying a healthy state in the report as shown below.