Cold starting IMS with dynamic resource definition

You perform a cold start when starting IMS for the first time, or after changing the nucleus in a system definition. IMS never uses information from a previous shutdown as input to a cold start.

During a cold start, resource and descriptor definitions are automatically imported from the IMSRSC repository, resource definition data set (RDDS), or the MODBLKS data set, or IMS comes up with no resources.

During a cold start, the partition status or access state will be copied from the HALDB master. If you export the HALDB master status to the RDDS or the repository, the status of the master and its partitions will be obtained from the RDDS or the repository.

Automatic import of resource and descriptor definitions is defined through the AUTOIMPORT parameter in the DYNAMIC_RESOURCES section of the DFSDFxxx member of the IMS PROCLIB data set

If AUTOIMPORT=AUTO is specified, these conditions determine the source of the imported resource and descriptor definitions:

If all of the following conditions are true, automatic import from the IMSRSC repository is enabled:
  • For MODBLKS resources, MODBLKS=DYN is specified to enable MODBLKS DRD in IMS.
  • For MSC resources, the MSC section of the DFSDFxxx member of the IMS PROCLIB data set is defined with MSCRSCS=DYN to enable MSC DRD in IMS.
  • For MSC resources, the MSC section of the DFSDFxxx member is defined with MSCREPO=Y to enable MSC resources to be stored in the IMSRSC repository.
  • The REPOSITORY section of the DFSDFxxx member is defined with TYPE=IMSRSC.
  • IMS is enabled with RM services (RMENV=N is not specified in the DFSCGxxx member of the IMS PROCLIB data set or in the CSL section of the DFSDFxxx member of the IMS PROCLIB data set)
  • The CSLRIxxx member of the IMS PROCLIB data set is defined for the repository with TYPE=IMSRSC.
  • The repository contains stored resource definitions for the IMS system.
  • RM is started with the repository enabled.
  • The RS address space is started and available.
If all of the following conditions are true, automatic import from an RDDS is enabled:
  • MODBLKS=DYN is specified to enable DRD in IMS.
  • The REPOSITORY section of the DFSDFxxx member of the IMS PROCLIB data set is not present.
  • Two or more system RDDSs are defined in the RDDSDSN() parameter of the DFSDFxxx member of the IMS PROCLIB data set.
  • All of the defined RDDSs can be allocated and read.
  • At least one of the RDDSs contains valid resource and descriptor definitions.