IBM i now has historical data support from Collection Services and graphical display of that data with Graph History in the Performance task of IBM Navigator for i.
Historical data combined with the power to view and analyze it across days, weeks, and years provides new insight about system performance.
Graph History can help you understand your data and how it changes over time. You will be able to identify trends, investigate performance issues from the past, or compare today’s performance with a previous time period that you select.
Historical Data
Collection Services’ new collection type *HSTFILE reduces and summarizes a subset of the Collection Services data to keep it over long time periods while conserving space.
Performance Data Investigator (PDI) will analyze and display this new historical data collection type.
To enable the concept of aging or decaying data, there are two levels of historical data: detail and summary. As the maximum collection duration increases, the number of metrics available decreases as shown here:
| Maximum duration of collection | Number of metrics available (variety of data) | |
| Collection Services data in *CSFILE | 24 hours | most |
| Historical Detail data in *HSTFILE | 60 days | fewer |
| Historical Summary data in *HSTFILE | 50 years | least |
The summary historical data is system level or summarized metrics. These are useful in identifying trends or detecting changes in a system over a long period of time.
The detail historical data is data from which the summarized metrics are derived as well as other relevant supplementary data. Only the top contributors for each metric will be stored as historical detail data.
Create Historical Data on a 7.3 System
To turn on the creation of historical data on a 7.3 system, use the Collection Services configuration panel. Select the check box for “Create historical data when collection is cycled”. This selection will be off by default. Continue to the Data Retention and Historical Data tabs to set other historical data options.
With these configuration options in place, on the next cycle of Collection Services historical data from all *MGTCOL objects in the configured library will be generated.
Once you have historical data, the new Graph History function in the Performance task on IBM Navigator for i will allow you to view this historical system performance data.
Visualizing Historical Data with Graph History Summary Charts
To view the historical data, select Summary in the new Graph History task section under Performance.
The majority of the new function for the 7.3 release is in the Summary charts. Detail charts will be enhanced in the future.
When the Summary chart is first displayed, it will show data for the past month. Use the slider or mouse to zoom in.
Context Panel
Use the context panel to view and modify the chart specifcs such as metric, report range, graph interval and dates.
The Metric field drops down to switch to any of the other available Summary charts.
The Report Dates field determines which dates will be displayed on the graph. The Graph Interval values available are based on the Report Dates range. The Graph Interval settings available depend on what report date range is selected.
The From Date and Time fields and To Date and Time fields allow you to select a custom range.
Top Contributors Chart
To view top contributor information for an interval, select a square or triangle data point. This allows you to see the top contributors for the metric during the time interval selected.
Property Data
From the Top Contributors graph, you can view property data for a job or task, memory pool, disk unit, or communications line by selecting a bar from the Top Contributor graph.
Requirements
Historical Data and the Graph History analysis tool is included with the base operating system on IBM i 7.3. For best results, make sure you have the latest level Group PTF for IBM HTTP Server for i installed on your system.
Conclusion
With this new Graph History function you can look back in time and better analyze your system performance over the long term. Turn on historical data now and in the future you will be able to see past system performance. You will have the best hindsight about what’s happening on your system.
Resources
IBM i Technology Updates page Performance on the web.
This week’s blog was written by Lora Powell. Lora is a member of the Performance Tools team in the IBM i development lab and works on the Performance Data Investigator.
Lora authored the article, A new way to analyze historical performance data on IBM i, that was recently published on the IBM i developerWorks site. This blog reviews some of the highlights of the historical data capabilities that were provided in the IBM i 7.3 release. See the referenced article for more information. Thanks Lora!
This blog post was edited to fix broken links on April 15, 2020.
This blog post was originally published on IBMSystemsMag.com and is reproduced here by permission of IBM Systems Media.