Migrating a non-DRD-enabled IMS system to DRD and the IMSRSC repository

To enable dynamic resource definition (DRD) with the IMSRSC repository, which is the recommended option for storing dynamically defined resources, you need to enable DRD and the Repository Server (RS) address space. For MODBLKS resources, you also need to import the resource definitions from the MODBLKS data set to the RDDS.

Recommendation: When you migrate to DRD for MODBLKS resources, use the IMSRSC repository instead of an RDDS because the repository function is the strategic direction for IMS.

To enable DRD with an IMSRSC repository:

Procedure

  1. Shut down IMS normally.
  2. Define the following DRD parameters in the DYNAMIC_RESOURCES section of the DFSDFxxx member of the IMS.PROCLIB data set:
    • AUTOIMPORT=AUTO, which specifies that IMS automatically imports resource definitions during a cold start.
      When AUTOIMPORT=AUTO, IMS searches data sources in the following order:
      1. IMSRSC repository
      2. RDDS
      3. MODBLKS data set and the DFSCLL3x member of the IMS.SDFSRESL data set

    • During migration to IMS 15, if the IMSRSC repository is enabled and the DFSDFxxx member has the AUTOEXPORT=AUTO explicitly defined, automatic export of MODBLKS resources to the IMSRSC repository is enabled after IMS 15 is cold started. If dynamic definition of MSC resources is also enabled, MSC resources are also automatically exported to the repository after IMS 15 is cold started. Any resource definition changes (creates and updates) are automatically exported to the IMSRSC repository at the next checkpoint.

      If you do not want to automatically export MODBLKS resource definitions to the IMSRSC repository, you must remove the AUTOEXPORT= parameter in the DYNAMIC RESOURCES section of the DFSDFxxx member and either let it default to AUTO or use one of the following values:
      • AUTOEXPORT= NO for no autoexport
      • AUTOEXPORT = RDDS for autoexport to the RDDS

      For MSC resources, automatic export must be enabled to store the MSC resources in the IMSRSC repository.

      When you are ready to enable autoexport to the IMSRSC repository you must modify the AUTOEXPORT= parameter in the DYNAMIC RESOURCES section of the DFSDFxxx member to explicitly specify AUTOEXPORT=AUTO or AUTOEXPORT=REPO.

  3. Enable DRD by specifying MODBLKS=DYN in either or both of the following locations:
    • The DFSCGxxx member of the IMS.PROCLIB data set
    • The COMMON_SERVICE_LAYER section of the DFSDFxxx member of the IMS.PROCLIB data set

    To enable DRD for MSC resources, you must also specify MSCRSCS=DYN in the MSC section of the DFSDFxxx member.

  4. If you are enabling DRD for MSC resources, specify MSCREPO=Y in the MSC section of the DFSDFxxx PROCLIB member to enable the IMSRSC repository for MSC resources.
  5. Specify attributes of the repository in the following members of the IMS PROCLIB data set:
    • FRPCFG member
    • BPE configuration parameters member
    • CSLRIxxx member
    • DFSDFxxx member
  6. Create the repository catalog pairs of data sets.
  7. Create the IMSRSC repository pairs of data sets.
  8. Start the Repository Server (RS) address space.
  9. Define the IMSRSC repository data sets to RS, which stores information about the IMSRSC repository in the RS catalog repository data sets.
  10. Optional: Start the Common Queue Server (CQS) with a resource structure.
  11. Enable the IMS Resource Manager (RM) to use the IMSRSC repository dynamically.
    • If the RM address space is running, issue the UPDATE RM command.
    • If RM is not running, restart RM so that it connects to the RS address space.
  12. Before you start IMS, specify the EXEC parameters DFSDF=xxx and, if MODBLKS=DYN was specified in the DFSCGxxx member, CSLG=xxx. These parameters identify which DFSDFxxx and DFSCGxxx members in the IMS.PROCLIB data set to use.
  13. Cold start IMS.

    If the IMSRSC repository is empty, during cold start IMS imports the resource definitions from the IMS.MODBLKS data set and the DFSCLL3x, DFSCLR0x, and DFSCLC0x members of the IMS.SDFSRESL data set to create the runtime resource definitions. The online change process for the IMS.MODBLKS data set is now disabled.

  14. After IMS is running, issue one of the following commands to export the runtime resource definitions to the IMSRSC repository:
    • For MODBLKS resources, the EXPORT DEFN TARGET(REPO) command
    • For all runtime resource definitions, including both MODBLKS and MSC resources, the /CHECKPOINT command
You can now use DRD to add (CREATE command), change (UPDATE command), or delete (DELETE command) the runtime resource definitions.

To ensure new and updated runtime resource definitions are recovered across an IMS cold start, issue the EXPORT DEFN TARGET(REPO) for MODBLKS resources or the /CHECKPOINT command for both MODBLKS and MSC resources to harden the definitions in the IMSRSC repository.

To ensure that deleted runtime resource definitions are not recovered across an IMS cold start, issue the DELETE DEFN command to delete the stored resource definitions from the IMSRSC repository.