Enabling global online change

Enabling global online change does not require that you shut down all the IMS systems in the IMSplex at the same time. You can enable global online change one IMS at a time. After all of the IMS systems have switched to supporting global online change, the IMSplex only supports global online change.

Global online change requires a CSL. The following steps assume that the CSL environment is already established. To enable global online change, you must perform the following steps once:

Procedure

  1. Define the OLCSTAT data set characteristics.
  2. Initialize OLCSTAT.

After you have defined and initialized the OLCSTAT data set, you can perform the following on one IMS at a time:

  1. Remove MODSTAT DD statements from IMS control region JCL.
  2. Remove MODSTAT2 DD statements from IMS control region JCL (if XRF).
  3. Define DFSCGxxx PROCLIB member data set parameters related to global online change.
    1. Specify OLC=GLOBAL to enable global online change.
    2. Specify OLCSTAT= with the name of the online change data set. All IMS systems in the IMSplex must specify the same OLCSTAT data set.
  4. Shut down IMS.
  5. Cold start IMS.

When migrating batch IMS systems, you can enable Coordinated (global) Online Change by modifying the DBBATCH JCL:

  • Add the OLCSTAT DD statement.
  • Remove the MODSTAT DD statement.