Tuesday 4 June 2013

Monitoring system performance for an SAP application

Before performance testing a live application, we would first need to understand the performance goals and requirements. By obtaining and analyzing the existing performance metrics, we get a thorough idea on the system performance and this can be used for further benchmarking purpose. And these data are extremely important if an upgrade activity has been planned in the future with which the existing performance is to be compared with. Crystal clear SLAs are to be defined in the requirement gathering phase itself and this needs to be agreed upon by the stake holders. Given below is the standard procedure for extracting the relevant data to analyze and set up the performance SLAs for an existing SAP GUI system before any major upgrades.





CCMS Monitoring Architecture:
Extracting performance metrics and logs from an SAP System 

Getting the preliminary data for performance testing is relatively easy with SAP systems owing to the inbuilt capability and reporting facility that SAP comes with. Before deep diving into these features, it is important that we understand some frequently used SAP terminologies. For instance, we are aware that any live SAP system will have a central “Computing Center Management System (CCMS)” which can be used to monitor, analyze and distribute the workload of clients and to display the resource usage of system components. From CCMS it is possible to monitor a CPU host system, the DB, OS and SAP services, i.e. we can obtain CPU utilization rate, average workload for last few minutes and so on

There are several inbuilt monitors available with SAP: Workload monitor, Global work load monitor, Operating system monitors, Database monitors etc. To obtain statistical data for the ABAP kernel, workload monitor may be used (ST03) and global work load monitor (ST03G) may be used to display statistical records for entire landscapes (SAP R/3 and non-SAP R/3 systems).Database monitors are used to obtain the KPIs of the DB system. The SAP official documentation covers the configuration and utilization of these monitors 

For analyzing the performance of a system, it is good to start with workload monitoring, especially the Response Time Distribution. In the workload monitor, we have different views for workload analysis (check official documentation). Transaction ST03 will fire the workload monitor and we can select the particular instance and duration to which we need the response time distribution from the workload tree. The workload distribution is obtained by selecting “Response Time distribution” in analysis view type 

The output area contains three tab pages with the following characteristics:

  • In addition, workload monitor can be used to display the no of users working on an instance, workload distribution, transaction response time details and their memory utilization, spool requests volume and much more. If we are concerned about workload distribution amongst individual service types, we might need to use global workload monitor (ST03G) 
  • Operating system monitors and Database monitors are useful when analyzing the performance of the OS and DBs (alert monitor – RZ20 may be used for the same). Below is the standard monitoring architecture diagram 
  • Most commonly used SAPGUI monitor transactions are ST03N, OS-Monitoring ST06, buffer related Monitoring ST02, DB Monitoring (ST04), user distribution Monitoring (ST07)