MSDBINIT data sets--GDGs vs. non-GDGs
If the MSDBINIT data set is a member of a generation data group (GDG), RCF processing will create a new generation whenever AUTO=N is used to start the IMS system. An additional generation is created when the RCF MSDB maintenance option is used (for example, TRCF=M).
If MSDBINIT is a member of a GDG, the back-up step in the IMS procedure for this data set should be omitted. If the MSDBINIT data set is not a GDG, the back-up step should be retained. RCF will set a return code to drive the back-up step whenever the MSDBINIT data set is changed.
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