Typical scenario and processes to run for unloading and reloading a DEDB

Typical scenario for DEDB Unload/Reload

The following is a checklist of the activities that are usually required to unload and reload one or more areas of a DEDB. Some steps are omitted when only database reorganization is being performed:

1. Perform the following pre-unload/reload planning.
   1. Determine the number of unload subtasks and output files, and calculate the storage requirements for FABCUR1.

      For the details, see the Unload Region Size Estimation Worksheet, Figure 1.

   2. Set up and tailor the unload JCL:
      • Control statements
      • Input and output files
      • Number of sort steps.
   3. Set up and tailor the required number of reload jobs.
   4. Set up a temporary ACB library and generate the new DBD and ACB.
2. Stop (that is, deallocate from the IMS control region) all areas involved in the maintenance process. If the application does not handle "FH" status codes, all transactions that access the database must be stopped.
3. Image copy all areas that will be unloaded and reloaded.
4. Run the unload job.
5. Run DEDB Pointer Checker against the image copy data sets. This provides statistics on the number of segments in the areas being unloaded/reloaded. This could be run concurrently with the unload/reload jobs.
6. Check any messages generated by FABCUR1, and verify segment totals on the Unload Audit Control report.
7. Run the reload jobs by specifying image copy and HASH check options.
8. Check any messages generated by FABCUR3, and verify segment totals on the Reload Audit Control report.
9. If image copy option was not specified in step 7, image copy all areas that were unloaded and reloaded.
10. If image copy option was not specified in step 7, run the DEDB Pointer Checker utility against the image copy data sets. Verify that the unload/reload produced clean areas with the correct number of segments.
11. Migrate the new DMB to the production ACB library.
12. Start the reloaded areas.