In the IBM i 7.2 release, there is a new function called “Batch Model”; the 7.2 announcement stated: “The Batch Model has been added, providing the ability to change environment variables, modeling how those changes would impact the batch window.” Batch Model is a utility that can help you understand your batch workloads and can assist in predicting the performance result of hardware changes (processors or disk) or an increasing workload on your batch window.
You will find Batch Model under Sizing within the Performance tasks in Navigator, as the following image shows. You must have the IBM i Performance Tools licensed program product (5770-PT1, option 1) installed in order for these tasks to be available.
Batch model runs over Collection Services data; you identify the timeframe that represents your batch application when creating the batch model. Once the model is created, you may need to calibrate the model; this is needed if the system didn’t create the model as you require. For example, your batch application may consist of several jobs and you must ensure those jobs and linkages (parent/child relationship) are correct.
Once your batch model has been correctly calibrated, you then use the Change Batch Model function to change various configuration components of your batch application. You can change the system model (processor) configuration, the disk configuration and the workload job characteristics (move, copy, delete jobs from the model. Once these changes are made, you analyze your batch model to get the results. Once the analysis is complete, you can investigate the results with the Performance Data Investigator. The Performance Data Investigator has a few ways to look at your modeled results, comparing the measured workload you started with to the results of the modeled workload.
One example is the resource utilization overview, as the following image shows:
You can use Batch Model on Collection Services data from the 6.1 or 7.1 releases. You do need to have a 7.2 partition to access the Navigator interface for Batch Model, but you can save your Collection Services data from 6.1 or 7.1 onto that 7.2 partition and select that older performance data when creating your batch model. This is very handy for sizing exercises if you are planning a HW or SW upgrade. Note: Support for the POWER8 hardware models is not yet available but will be coming soon in a PTF.
The development team that worked on creating Batch Model has provided an article, “How to use the Batch Model performance tool” on developerWorks, where you can find a more in-depth review of this tool.
Some of you may be familiar a tool called Batch/400. Batch/400 was a utility written many years ago as an as-is tool to help predict the impact of changes on a batch application; it had a command called BCHMDL. While I was writing this article, I thought perhaps I might be able to find some historical references for the Batch/400 utility. It turned out to be a bit difficult to find much documentation about it. An Internet search on “Batch/400” revealed “Batch 400 American Stout brewed by Swamp Head Brewery.” An Internet search on “BCHMDL” told me about the British Columbia Hockey League … with a couple results more along the line of what I was really looking for.