Overview of the global online change function

Global online change is an IMS™ function to change resources for all IMS systems in an IMSplex. A Master IMS control region, as specified by the user or by an Operations Manager (OM), uses Resource Manager (RM) to coordinate the phases of online change with other IMS systems in an IMSplex.

Restriction: The online change function is not supported for the following types of resources when dynamic definition of the resources is enabled:
  • MODBLKS resources when dynamic resource definition is enabled.

For member online change, the member names specified on INIT OLC TYPE(ACBMBR) NAME(xxx) and their associated members are copied from staging to active. Staging may have members that are not copied. You can add or change individual members of IMS.ACBLIB and bring these members online without quiescing the IMSplex or requiring a full refresh of the active ACB library.

For library switch online change (local or global) the active and inactive libraries are swapped.

For more information about changing or adding members to IMS.ACBLIB online, see Changing or adding IMS.ACBLIB members online.

If you are running an IMSplex that does not use RM, you can specify the CSL global parameter RMENV=N in the DFSCGxxx IMS.PROCLIB member. If this parameter is specified, IMS does not require RM and will not use RM services, but type-2 command support is available. If OLC=GLOBAL, use the INITIATE OLC command to initiate local online change. The OLCSTAT data set must be defined. This data set cannot be shared between IMS systems.

With global online change, the Master IMS control region coordinates online change of the following resources among all the IMS systems in an IMSplex:

Parent topic: The online change function