Cold starting an IMS system that uses an RDDS

IMS systems that use dynamic resource definition to manage application programs, databases, Fast Path routing codes, and transactions can save resource definitions to a resource definition data set. During a cold start, IMS can use the definitions from the MODBLKS data set or the resource definition data set (RDDS) to create runtime resource definitions.

If your IMS system is not configured to import the resource definitions automatically at cold start, you can issue the IMPORT command after the restart process is complete. The IMPORT command, as well as all of the other type-2 dynamic resource definition commands, requires that the SCI and OM CSL components be started.

You can successfully start an IMS for the first time with DRD enabled and no resources defined yet. After the restart process completes, you can define resources dynamically by using the appropriate CREATE commands.

Before you shut down a running IMS system that uses dynamic resource definition for a cold start, you must export the resource and descriptor definitions that are currently defined in your online system to the RDDS. If you do not, any changes made to the resource definitions in the online system will be lost at the next cold start or emergency restart with the COLDSYS parameter.

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.

If an error occurs while trying to access an RDDS during the automatic import process, automatic import terminates abnormally. IMS either continues with the cold start process without any runtime resource definitions defined, or IMS stops the cold start process. If an error occurs during automatic import processing because of an invalid resource or descriptor definition, one of the following situations occurs:
  • Automatic import processing terminates abnormally, and IMS cold start terminates abnormally with a U3397 abend.
  • Automatic import processing continues, and the resource in error is marked and given a not-initiated status (NOTINIT).
The action IMS takes depends on the values specified for the RDDSERR and the IMPORTERR parameters in the DFSDFxxx member of the IMS PROCLIB data set.