Scenario 2: Viewing past system health
If your system is not performing well and you want to know when this started, you are interested in snapshots that were taken earlier and are probably no longer displayed to you. The following scenario tells you how to view past system health using the data view that you created and helps you understand the chart and the values displayed.
For the purpose of this scenario, it is assumed that you have collected locking data for at least a couple of minutes and you selected a refresh time of 10 seconds and a threshold of 60 units per second.
Perform the following steps:
- To start the display of past system health, in the
toolbar, select History in the Data field.
The history slider is activated and the Refresh field is disabled.
- Move the slider to a time during which snapshots were collected and wait a couple of seconds to receive the data.
The chart has changed as follows:
- The chart shows the eight snapshots collected from the time that
the slider indicates. The time of the first and last snapshots displayed
is shown below the chart.
Note that the collection of the current snapshot continues in the background. So when you leave history mode, the most recent snapshots are displayed.
- The scale of the y-axis, the place of the threshold
line, and the size of the bars changed:
When you view the current system health you can specify how often the snapshots are refreshed. History snapshots are, however, displayed at the interval at which the OMEGAMON® Collector collects data, which is 60 seconds for the recording interval. Because the refresh rate is now 60 seconds (instead of the 10 seconds you previously specified), the y-axis of the chart now ends above 3500 and contains a (threshold) line at unit 3600 and the size of the bars is adjusted accordingly.
For more information about how to select history snapshots in different ways, see Viewing history data.
The number of snapshots available is limited by the size of the history file on the host. If their number exceeds this size, the oldest snapshot is deleted. Your chart reflects this change and the timestamp to the lower left of the chart is adapted.