Case 5: Time sequence gaps in CDS records, journal records also missing

During a reorganization, user error may cause time sequence gaps in the CDS records, along with missing journal records.

Take the case where an installation uses generation data sets (GDSs) when reorganizing the CDSs. The user attempts to use IDCAMS REPRO to create an output data set for a migration control data set (MCDS). The MCDS is not successfully copied to the output data set, but the user does not notice. Then the user employs IDCAMS REPRO to create a new, reorganized MCDS, not knowing that the input data set is actually the last version of the MCDS successfully copied and is not the current MCDS at all.

After the reorganization completes, the administrator thinks that everything went as planned, and continues with everyday processing.

DFSMShsm may run with an old copy of the MCDS for a week before a high number of data set recall failures signal that there is a problem. The old MCDS that is being used, of course, does not contain the more recently migrated data sets.

When the storage administrator finally discovers what has happened, he looks to see if he can recover from a backup version. He backs up once a day, and keeps three backup versions. The reorganization, however, was performed seven days ago. That means he doesn't have any backups before when the reorganization occurred, for either the journal or the MCDS.

Recovery in this instance is very complicated. The best course of action is to call your IBM® Area Storage Specialist for recovery assistance.