Objective of capacity planning
In my post “Performance control in SAP projects/development“, it is pointed out that part of “total performance control” strategy is “capacity planning”. Through capacity planning, we make sure that SAP system has enough hardware to support activities/workload through the project. Simply put, capacity planning is to get business requirement in terms of business activities and throughput, assess hardware requirement for such activities and throughput which is laying a solid basis for business application performance. Capacity planning in this regard is called “system sizing” as well. Following chart is showing relation among Business input, capacity and performance:
1. Capacity planning process
Following chart is illustrating a process I used in my SAP projects:
You collect information about the project based on your sizing questionnaires. Then analyze information provided by the project to make sure it is consistent and rationale. In the end, you propose capacity result which needs by the project. As illustrated by the chart, capacity planning process is an iterative process which involves capacity professional and project resources.
2. When to start capacity planning
So you might wonder when I should start capacity planning process in a SAP project? Based on software lifecycle, the capacity planning should start at the following point/phase
Business requirement investigation phase
Capacity planning at this phase is based on finalized business requirement/business blue print. This is an initial capacity planning which can be used for budget planning.
Business Acceptance Testing phase
At this phase, you need to verify whether there is any significant change to input used in previous sizing. So you can tune the previous sizing result. Since solution is more stable in BAT phase, you can also verify/tuning hardware forecast based on customized solution and BAT testing result.
This is to monitor actual capacity usage in production box to ensure that capacity usage is in line what is projected in BAT phase and tune capacity as needed.
Sizing is normally a repeated effort not a onetime event. After sizing, you should always need to do sizing again if there is a significant change to data used in previous sizing.
3. What is capacity planning approach and tools
Finally, you might want to ask what is sizing approach/strategy and tool? SAP has used two approaches for capacity planning in its tool, please refer to following chart for details –
The SAP tool is called “quick sizer”. It is a web-based tool allowing you to do user-based and/or throughput-based sizing. Based on input guided by SAP sizing questionnaires, this tool would provide CPU, Memory, disc-space and networks bandwidths forecast. CPU demand is measured in SAPS which can be mapped to specific vendor hardware. If you would like to know more details on this SAP tool, click here. If you have SAP OSS logon, you can click here for more training documents on quick sizer.
Your organization might develop the local tools/models for capacity planning –especially when you already have SAP production environment. Dependant your production box and your project scope, your local tool can produce more accurate sizing result since your local tool knew more about your local SAP box/business solution.
It is critical to make reasonable effort to have accurate business input. Also SAP quick sizer is based on standard sap solution – it has no information about configuration, modification, development which your project has introduced. So it is important to verify/tune SAP sizing result in BAT phase especially when there is a lot of customization and local development in the project based on my experiences. This type of sizing can not supported by SAP quick sizer, You need performance and capacity expert to assess hardware requirement based on BAT performance data.