Falling back from using the IMSRSC repository for MODBLKS resources

After using the IMSRSC repository to store MODBLKS resource and descriptor definitions, you can fall back to using a resource definition data set (RDDS) or the MODBLKS data set instead.

1. Copy the stored resource definitions for the IMS from the repository to a non-system RDDS using the Repository to RDDS utility (CSLURP20).
   If multiple IMS systems are falling back, copy each set of IMS resource definitions to their own RDDS data set.
2. If falling back to the MODBLKS data set, generate MODBLKS or Stage-1 output using the DFSURDD0 utility.
   The input to the DFSURDD0 is the output RDDS generated from the CSLURP20 utility.
3. Shut down the IMS system that is falling back.
4. Issue the DELETE DEFN command for all of the MODBLKS resource types that have resource definitions in the IMSRSC repository for the IMS that is falling back.
   Issue the DELETE DEFN command with keywords FOR(IMSID(IMS1)) and NAME(*) for each resource type. For example, if IMS1 is falling back, to delete database resources, issue:

   DELETE DEFN TARGET(REPO) NAME(*) TYPE(DB)FOR(IMSID(IMS1))

5. If the IMSRSC repository is no longer required for any other resource and descriptor definition, remove the REPOSITORY section from the DFSDFxxx member of the IMS PROCLIB data set.
6. If the IMSRSC repository is no longer required for any other resource and descriptor definition, change the specification for automatic import from the repository to RDDS or MODBLKS.
   Complete one of the following steps:

   • If you want to import the definitions from an RDDS, change the DYNAMIC_RESOURCES section of the DFSDFxxx member to indicate AUTOIMPORT=RDDS or AUTOIMPORT=AUTO to ensure that the RDDS is read during cold start. Then, set one of the system RDDS data set names in the DYNAMIC_RESOURCES section of the DFSDFxxx member to the name of the RDDS generated in Step 1. The other system RDDSs defined in the DFSDFxxx member must be empty or have an earlier time stamp than the RDDS generated in Step 1.
   • If you want to import the resources from a MODBLKS data set, change the DYNAMIC_RESOURCES section of the DFSDFxxx member to indicate AUTOIMPORT=MODBLKS or AUTOIMPORT=AUTO to ensure that the MODBLKS data set is read during cold start. If AUTOIMPORT=AUTO is specified, the repository and RDDSs, if they exist, must be empty. During IMS cold start, IMS reads the MODBLKS data set to create the runtime resource definitions.
7. Perform a cold start of IMS.