The Simplest Approach®

Perhaps the easiest way to assign APPC/MVS LUs to a generic resource group is to:

  1. Review the LUADD statements of existing APPC/MVS LUs to:
    • Determine which would serve as good models for members of a specific group, and
    • Decide how many members you want to have in each group, and on what z/OS system each member will reside.

    As you make these decisions, remember the sequence of events in Figure 1, and the points in Distributing Session Workload.

  2. For each model LU, consider "swapping" the real name for the generic resource name; that is:
    • Update the LUADD statement to use the specific name as the generic resource name, which is specified on the GRNAME parameter, and
    • Define a new specific name for the LU.

    To avoid potential problems, make sure the generic resource name is unique within a single network. Within a single system, VTAM® does not allow the use of the same name for a USERVAR and a generic resource group. Within a single network, VTAM does not prohibit the use of a generic resource name that is the same as a USERVAR, alias, or real LU name, but such duplication might cause undesired results for Allocation requests, or might make problem determination more difficult. For example, the use of USERVARs might cause similar timing problems as described in Step 4; once a local LU establishes a session with a partner LU, using a USERVAR for the partner LU name, subsequent Allocate requests with the partner's real LU name will fail. See z/OS Communications Server: SNA Network Implementation Guide for more information about USERVARs and aliases.

  3. Make a copy of the updated LUADD statement for each additional member in the group, and change the specific name in each copy.
  4. Use those copies in the appropriate APPCPMxx parmlib member for the z/OS systems on which the group members will reside.

With this approach, the migration effort is reduced to changing only LU definitions in parmlib, rather than changing those definitions and all the Allocate calls issued by TPs that run at your installation. Allocate calls do not necessarily need to be changed, because the names they specify for partner LU now might be the generic resource group names.

See Defining LUs to a Generic Resource Group for the procedure for assigning generic resource names for APPC/MVS LUs.

Parent topic: Deciding which APPC/MVS LUs should be Members of a Generic Resource Group