3. USAGE GUIDELINES › 3.1 Setting Up VCC for Operation › 3.1.3 Job Operational Flow

3.1.3 Job Operational Flow

This section describes the operation logic flow of the VCC
job with respect to the integrity of the data that VCC
generates.

When recording to SMF:

  When VCC completes processing for a volume, a volume total
  record is generated and written.  If VTOC processing does
  not complete normally, this record is not written.  During
  VCA processing, any data set and catalog records will be
  ignored if they represent a volume for which no total
  record was found.  This makes sure that data for partially
  processed volumes is ignored by VCA.

When recording to a data set:

  The VCC job collects DASD space utilization data.  The
  control file is used to time stamp the VCC processing start
  time, keep track of previous process start time and volumes
  processed, and to make sure that backups are done if SMF is
  not chosen as the VCC recording medium.

  The VCCDATA data set is a reusable file in which VCC will
  record its SMF records.  VCC ensures that the disposition
  for this data set is always OLD.  MOD is not allowed.

  The control file is not updated until the end of the VCC
  data collection process (this step).  Therefore, if this
  step does not complete successfully it can be rerun any
  number of times until a successful step termination occurs.
  Because the VCCDATA data set is not used as input to the
  CA MICS Data Base, CA MICS cannot process a partial data
  collection run.  And because the VCCDATA data set is
  reusable, CA MICS will see only the latest data and not
  data from several VCC runs strung together.

  When the control file is updated, a flag is set that
  indicates that a backup (STEP2) is needed.  If a backup is
  not successfully done, then subsequent VCC runs will fail
  if this flag is still on.  The last step (STEP3) resets
  this flag if the condition code for STEP2 is 0.