Migration steps

General migration tasks for current IMS installations include researching Preventive Service Planning (PSP), determining hardware and software requirements, backing up your system, and other tasks.

1. Plan and prepare for the new version of IMS
   1. Create a migration plan.
   2. Verify software and hardware requisites that are listed in either the announcement letter or the Program Directory.
   3. Identify the Migration/Coexistence maintenance that you need to apply by using either the SMP REPORT MISSINGFIX (FIXCAT) command or by checking the PSP Bucket.
   4. Review the migration and coexistence considerations and the new functions in the IMS Release Planning guide. If you are skipping one or more releases, review the Release Planning Guide for each release you are skipping.
   5. Determine requirements for your IMS Tools or vendor products.
      • For information about IBM® IMS Tools:
        • IBM IMS Tools and IMS Version 15.3 Compatibility
        • IBM IMS Tools and IMS Version 15.2 Compatibility
      • Contact IBM Software Support for all other IBM Tools related to IMS.
      • Contact vendor support for non-IBM tools and products that are related to IMS.
   6. Order the product.
      The product can be ordered from Shopz website.
2. Install the product.
   1. Review the PSP Buckets by searching for the upgrade name IMS1504 at Preventive Service Planning buckets for mainframe operating environments website and reviewing the upgrade information. If you are skipping a release, also review the upgrade information for the release you are skipping.
      Tip: Check the Installation Information and General Information sections for guidance.
   2. Perform SMP/E processing (RECEIVE, APPLY, ACCEPT).
   3. Run the IMS Installation Verification Program (IVP).
   4. Customize to your environment. Coordinate with your security administrators and database administrators, as appropriate.
   5. Re-assemble any user code that accesses IMS control blocks or log records.
   6. Re-work USERMODS as necessary, including the DFSIDEF0 module, if used.
   7. Ensure that appropriate dynamic allocation members are available to the new environment.
      This step might be performed by or with a database administrator.
   8. Ensure that your user exits are available to the new environment.
   9. Optional: Optionally, compare the members in the current SDFSRESL library to the members in the new SDFSRESL library to make sure that nothing that IMS needs is missing in the new SDFSRESL library.
3. Prepare for implementation
   1. Implement migration and coexistence maintenance that was identified in step 1.c.
   2. Prepare the z/OS® interfaces by, at a minimum, installing the IMS type-2 and type-4 SVCs. Depending on your IMS configuration, you might need to take other steps to prepare the z/OS interface. For more information, see z/OS interface considerations.
   3. Verify that the RECONs are ready for upgrade by issuing the DBRC command CHANGE.RECON UPGRADE CHECKUP.
      This step might be performed by or with a database administrator.
   4. Upgrade the RECONs by issuing the DBRC command CHANGE.RECON UPGRADE.
      This step might be performed by or with a database administrator.
   5. Prepare libraries for the new version by:
      1. Perform the system definition (SYSGEN) process with "ALL" specified on the IMSCTRL macro.

      2. Create a set of ACB libraries for the IMS version by using the new version of the ACB Maintenance utility. This step is typically performed by a database administrator.

         Attention: ACBs must always be generated by using the utilities from the IMS version in which they are used.
      3. If necessary, change procedures and jobs, ensuring that the DRA and JCL in DRA client address spaces, such as CICS®, Db2 for z/OS stored procedures (SPAS), and so forth, point to the correct SDFSRESL data set.
   6. Prepare and test a fallback plan. See Fallback considerations.
      This step is typically performed with database administrators.
   7. Compare the current amounts of CSA, ECSA, PRIVATE, and EPRIVATE storage that is used to that of the new IMS version.
      1. Compare the CSA storage requirements of the new and current IMS Versions and adjust the IMS region sizes as necessary.
      2. Adjust IMS pool sizes for the new version as necessary.
      3. Take SVC memory dumps of your current IMS address spaces before migration and keep them for comparison purposes.
   8. Review existing automation and update as appropriate. See Message and code changes in IMS 15.4.
      This step might be performed by an automation or operations group.
   9. Determine HIPER and PE exposure.
      1. Obtain current enhanced hold data from the Enhanced HOLDDATA for z/OS website.
      2. SMP/E RECEIVE current enhanced hold data
      3. Generate and analyze HIPER and PE exposure report by issuing the SMP/E command REPORT ERRSYSMODS pointing to your new TARGET zone. If needed, contact IBM Software Support for help.
   10. Back up product libraries of old system, for example SDFSRESL, MODBLKS.
   11. Identify any databases that have extended error queue elements (EEQEs) by issuing the IMS command /DIS DB EEQE and recover the databases as appropriate.
       This step is typically performed by database administrators.
4. Implement the system
   1. Confirm that no databases have EEQEs by issuing the IMS command /DIS DB EEQE. If any do, resolve them before you proceed.
      This step is typically performed by database administrators.
   2. Shut down old system
   3. Ensure that shutdown completes successfully
   4. Ensure that the archive of the logs runs successfully (OLDS)
   5. Incorporate the new product libraries into your environment
   6. Implement any changes to automation
      This step might be performed by an automation or operations group.
   7. Cold start the new system by issuing the IMS command /NRE CHKPT 0 FORMAT ALL
   8. Test your application programs
      This step is typically performed by the respective lines of business.