Determining if control data sets are accurate

During recovery processing, a control data set can lose synchronization with the actual conditions in the system. DFSMShsm provides a command allowing you to determine how closely the control data sets match the actual system conditions and to repair minor discrepancies.

The AUDIT command detects and reports discrepancies about data set information from:
An example of the AUDIT command is: 
AUDIT DATASETCONTROLS(MIGRATION) -
     NOFIX OUTDATASET(outputname) REPORT(ERRORS)

In processing this command, DFSMShsm reads each data set record in the MCDS. DFSMShsm compares the information about each data set to the information contained in the system catalogs and in the VTOCs of any DASD volumes that the catalogs or the MCDS indicates the data set resides on. DFSMShsm does not try (because of the NOFIX parameter) to reconcile any differences that it finds. Instead, DFSMShsm sends a report of any errors to the data set specified by the OUTDATASET parameter.

Recommendation: The OUTDATASET contains executable FIXCDS commands to create or correct CDS records, but those CDS changes are only a subset of the corrective actions taken by AUDIT. In addition, the CDS records may be read multiple times during the course of an audit. If the NOFIX option is specified, the changes to a record generated on its initial read are not reflected in that record when it is read a subsequent time, which may result in incorrect actions being taken. For these reasons, the later submission of output from an AUDIT NOFIX as a substitute for an AUDIT FIX is generally discouraged.

The AUDIT command helps determine how closely the control data sets match the actual system conditions. There are Access Method Services commands that verify the structure of the CDS. The Access Method Services DIAGNOSE and EXAMINE commands can be used to validate the VSAM volume data set data structures and analyze the structural consistency of the index and data component of a key-sequenced data set.

Related reading

For more information about the AUDIT command, see AUDIT Command: Auditing DFSMShsm.

Parent topic: Maintaining DFSMShsm control data sets