Use historical data collection and reporting to gather useful metrics about your managed network. You can also use historical data with the chart baselining tools for predictive analysis and in situation modeling for key performance indicators.
The History Collection Configuration window enables you to configure historical data collection for individual attribute groups and specify from which managed systems to collect, how frequently to collect the data, where to store it for the short-term, and whether to save data long-term to a data warehouse. You can create multiple historical collections for an attribute group, each with different collection settings and managed system distributions, and you can write filtering formulas to collect only the data samples that meet the filter criteria.
The Object Group editor enables you to combine historical data collections into groups and assign managed systems. With historical collection groups you can easily turn on and turn off historical data collection at specific managed systems or groups of managed systems by changing the distribution.
You know that historical data collection has been enabled for the attributes in a view when you can see Time Span in the view's toolbar. The view shows current data samplings unless you use this tool to specify a broader time period. The first 24 hours of collected data is retrieved from the short-term history files; beyond 24 hours, the data is pulled from the data warehouse.
Historical data is valuable for use in chart baselining and situation modeling. Applying historical data to chart baselines and situation modeling enables you to perform predictive analysis and fine tune situations.
Requests that return large amounts of data can negatively affect the performance of monitoring servers, monitoring agents, and your network. For attributes or views that return considerable amounts of data, try to limit the time span to as short a period as will provide the required information.
Be aware that if this is a newly configured historical data collection, you will see the historical data samples that have been collected and no more. For example, if you created a historical collection and assigned it to a historical collection group an hour ago, you will see only the last 1 hour in the chart or table view even if you selected, say, the last 8 hours.