Configuring an application server to use the WLM even distribution of HTTP requests function

By configuring your application server to use the WLM even distribution of HTTP requests function, HTTP session objects can be evenly distributed by workload management (WLM) to the servants in your configuration. You can use this task to distribute HTTP session objects in a round-robin manner among several servants instead of the normal situation where there is a servant affinity, and HTTP session objects reside in one or two servants.

1. In the administrative console, set the WLMStatefulSession property to true.
   1. Expand Servers > Server Types and click WebSphere application servers.
   2. Click the name of the server that you want to use the WLM even distribution of HTTP requests function.
   3. Under Server Infrastructure, expand Administration and click Administration services.
   4. Under Additional properties, click Custom properties.
   5. Click WLMStatefulSession and change the value in the Value field to true if it is currently set to false.
      If the custom property does not exist, click New, add WLMStatefulSession to the Name field, and add true to the Value field.

      If the property, WLMStatefulSession exists, its setting takes precedence over any setting for the environment variable wlm_stateful_session_placement_on. If WLMStatefulSession does not exist, then you can set wlm_stateful_session_placement_on to true (or accept the default, false) to establish (or not establish) an even distribution of HTTP requests.

   6. Click Apply and then click Save to save your changes to the master configuration.
2. Set the optimal minimum and maximum number of servants for the workload.
   Set the minimum and maximum number of servants to handle the expected number of HTTP sessions with affinity. The minimum number of servants should be greater than one.
   If, for example, you expect 15,000 HTTP session objects are established in the server during the day, then you might set the minimum number of servants to some value larger than one. The minimum of servants is dependent upon the size and number of the HTTP session objects. However, the initial arrival rate of client requests establishing the affinity, the frequency of client interaction, the duration of each client interaction (CPU time and thread occupancy time), and the length of time that the HTTP session object is maintained also need to be considered when establishing the minimum value for the number of servants.
   1. To set the number of servants, click Servers > Server Types > WebSphere application servers server_name Server instance.
   2. Set the minimum and maximum number of servants.
   3. Click Save and synchronize to apply the changes.
3. If you use a classification mapping file instead of a common workload classification document, and you specify more than one transaction class on a mapping rule for the managed round-robin support that the product provides, you should remove this section from your classification mapping file.
   You should use a common workload classification document instead of a classification mapping file because support for the classification mapping file is deprecated. However if you use a classification mapping file, and that file contains a line similar to the following:

   TransClassMap *:8080 /Dynacache1Web1/Servlet1 TCLASS1 TCLASS2 TCLASS3

   Modify this line such that it specifies only one transaction class. For example, you might change the preceding line to the following line:

   TransClassMap *:8080 /Dynacache1Web1/Servlet1 TCLASS1

   You also must update the z/OS workload manager policy to remove the extra service classes that are only required if you want to use the managed round-robin support that the product provides. Following is an example of how to remove the extra service classes:

     Subsystem-Type  Xref  Notes  Options  Help                                 
    --------------------------------------------------------------------------   
                     Modify Rules for the Subsystem Type     Row 9 to 16 of 16   
    Command ===> ____________________________________________ SCROLL ===> CSR    
                                                                                 
    Subsystem Type . : CB          Fold qualifier names?   Y  (Y or N)           
    Description  . . . Component Broker requests                                 
                                                                                 
    Action codes:   A=After     C=Copy        M=Move     I=Insert rule           
                    B=Before    D=Delete row  R=Repeat   IS=Insert Sub-rule      
                                                                 More ===>       
              --------Qualifier--------               -------Class--------       
    Action    Type       Name     Start                Service     Report        
                                             DEFAULTS: AZAMS1      RBBDEFLT      
     ____  1  CN         AZSR01   ___                  AZAMS1      RAZAMS1       
     ____  2    TC         TCLASS1  ___                AZAMS1      RAZAMS1       
     _d__  2    TC         TCLASS2  ___                AZAMS2      RAZAMS1       
     _d__  2    TC         TCLASS3  ___                AZAMS3      RAZAMS1       
     ____  1  CN         AZSR02   ___                  AZAMS2      RAZAMS2       
     ____  1  CN         AZSR02   ___                  AZAMS3      RAZAMS3       
   ****************************** BOTTOM OF DATA ****************************** 

4. Restart the server.
   The server recognizes the WLMStatefulSession property after it is restarted.