If you are running z/OS 1.2 or higher, you can use the administrative console to provide the job control language (JCL) PROC name for the servant and the JCL Parm for the servant and thereby set up a dynamic application environment. Even if you set up a dynamic application environment, you must set the WLM goals for your environment.
Proper WLM goals can significantly affect your application throughput. The WebSphere Application Server address spaces should be given a fairly high priority. When setting the WLM goals for your z/OS system, you might want to:
Java garbage collection runs under this classification. Java garbage collection is a CPU and storage intensive process. If you set the velocity goal too high garbage collection can consume more of your system resources than desired. If your Java heap is correctly tuned, garbage collection for each servant should run no more than 5% of the time. Also, providing proper priority to garbage collection processing is necessary since other work in the servant is stopped during much of the time that garbage collection is running.
JavaServer Page file compiles run under this classification. If your system is configured to do these compiles at runtime, setting the velocity goal too low can cause longer delays waiting for JavaServer Page file compiles to complete.
Application work is classified under the work manager.
You should make the response time goals achievable. For example, a goal that 80% of the work will complete in .25 seconds is a typical goal. Velocity goals for application work are not meaningful and should be avoided.
Your goals can be multi-period. This might be useful if you have distinctly short and long running transactions in the same service class. On the other hand, it is usually better to filter this work into a different service class if you can. Being in a different service class will place the work in a different servant which allows WLM much more latitude in managing the goals.
Application-Environment Notes Options Help -------------------------------------------------------------------------- Modify an Application Environment Command ===> ______________________________________________________________ Application Environment Name . : BBOASR2 Description . . . . . . . . . . WAS.V40.WB02 Application server Subsystem Type . . . . . . . . . CB Procedure Name . . . . . . . . . BBOASR2S Start Parameters . . . . . . . . IWMSSNM=&IWMSSNM __________________________________________ __________________________________________ Limit on starting server address spaces for a subsystem instance: 1 1. No limit 2. Single address space per system 3. Single address space per sysplexWhen the WLM configuration is set to no limit, you can use the wlm_maximumSRCount=x and wlm_minimumSRCount=y variables to control the maximum and minimum number of servants. To specify values for these variables, in the administrative console, click Severs > Application servers and select the appropriate application server.