CICS forward recovery

Some types of data set failure cannot be corrected by backward recovery; for example, failures that cause physical damage to a database or data set.

Recovery from failures of this type is usually based on the following actions:
  1. Take a backup copy of the data set at regular intervals.
  2. Record an after-image of every change to the data set on the forward recovery log (a general log stream managed by the MVS™ system logger).
  3. After the failure, restore the most recent backup copy of the failed data set, and use the information recorded on the forward recovery log to update the data set with all the changes that have occurred since the backup copy was taken.

These operations are known as forward recovery. On completion of the forward recovery, as a fourth step, CICS® also performs backout of units of work that failed in-flight as a result of the data set failure.