IMS failure recovery

When a failure occurs, you must perform the correct recovery and restart procedures to ensure system integrity. You can use the IMS control region Extended Specified Task Abnormal Exit (ESTAE) routines to clean up resources after an IMS abend.

The reason for the abnormal termination and the results of cleanup processing have a great effect on the subsequent restart process. The processing sequence of these routines is as follows:

  • The storage management task ESTAE routine writes recovery data to the restart data set (RDS) and then closes the RDS.
  • The IMS control task ESTAE routine terminates all dependent regions and issues message DFS629I.
  • All ESTAE routines attempt to purge the OLDS log buffer and to write a termination log record.
  • The ESTAE routines tell DBRC to sign off abnormally.
  • The ESTAE routines tell IRLM to quit, and either retain or release locks, based on whether DBRC indicates that databases have been updated.
  • The ESTAE routines disconnect XRF alternate subsystems from the z/OS® availability manager to perform I/O prevention.

In addition, the IMS resource cleanup module cleans up resources whenever IMS terminates. It releases the common storage area (CSA), closes DBDSs, deletes the subsystem interface control block, closes the VTAM® Access-method Control Block (ACB), and issues message DFS627I.

If you use the DL/I address space (you specified LSO=S in the IMS procedure), IMS issues message DFS603I to indicate that cleanup is successful.