Upgrading the RECON data set

You are not required to change the MINVERS value to '15.1' when you migrate to IMS 15. Change this value only after you verify that you do not need to coexist with an earlier version of IMS, will not need to fall back, and when you need to use new functions that require the MINVERS value to be set to '15.1'.

Attention:
  • Do not issue the IMS 15 CHANGE.RECON UPGRADE command to upgrade the RECON data sets until all IMS Version 13, IMS 14, and IMS 15 systems that access the RECON data sets have the correct supporting products in place and have been tested for IMS 15 support.
  • Because Remote Site Recovery (RSR) is no longer supported after IMS 14, you must remove all Global Service Group (GSG) information before migrating to IMS 15. Issue the LIST.GSG command to identify any GSG and issue the DELETE.GSG command to remove it before upgrading the RECON data set.

Migration to IMS 15 from IMS Version 13 or earlier versions may be achieved by migrating to the IMS Version 13 or the IMS 14 RECON data set format first and then using IMS 15 to issue the CHANGE.RECON UPGRADE command.

To upgrade an IMS Version 13 or IMS 14 RECON data set:

  1. Apply the IMS 15 coexistence Small Programming Enhancements (SPEs) to all earlier versions of IMS systems before you upgrade the RECON data set. For a list of the coexistence SPEs (APARs/PTFs) for DBRC RECON data sets, see Overview of coexistence APARs.
    Attention: Jobs that access the RECON data set and do not create subsystem records, such as the Database Change Accumulation utility (DFSUCUM0) and the Database Recovery Control utility (DSPURX00), are not protected from having the RECON data set upgraded while they are running on a version of IMS that does not have the appropriate migration/coexistence SPE applied. When these types of jobs access the RECON data set after the upgrade, the results might be unpredictable. Ensure that no such jobs are running when you upgrade the RECON data set.
  2. Ensure that you have two active RECON data sets (COPY1 and COPY2) and a spare data set when you upgrade the RECON data sets while other jobs are accessing them.
  3. Before issuing the CHANGE.RECON UPGRADE command against the production RECON data sets, upgrade a copy of the production RECON data sets to verify that the upgrade will complete successfully.
  4. Optionally, issue the CHANGE.RECON UPGRADE CHECKUP command. This command checks the status of the RECON data set and records to verify whether the RECON data set is in a state that allows an upgrade. No RECON data set records are changed as a result of issuing the CHANGE.RECON UPGRADE CHECKUP command.
  5. Issue the CHANGE.RECON UPGRADE command by using either the IMS 15 DBRC Recovery Control utility (DSPURX00) or the IMS 15 DBRC Command API request. This command:
    • Upgrades the RECON data set without shutting down all IMS activity.
    • Uses the DBRC I/O recovery algorithms to recover from any failures during upgrade (so you do not need to back up the RECON data set before you upgrade).

    After this command successfully completes, DBRC sets the value for MINVERS (the minimum version of IMS that can sign on to DBRC) to '13.1' if the value was less than '13.1'. You can display the MINVERS value in the output for a LIST.RECON command or a Query request using the DBRC API.

    Recommendation: If you use DBRC command authorization, consider setting the RECON qualifier as part of your migration process. You can set the RECON qualifier when you upgrade by adding CMDAUTH parameters to the CHANGE.RECON UPGRADE command, or after the RECON has been upgraded by issuing a CHANGE.RECON CMDAUTH command. If CMDAUTH parameters are specified on the CHANGE.RECON UPGRADE command, the RECON is upgraded first and then other parameters (such as CMDAUTH) are processed.

    For details about the CHANGE.RECON UPGRADE command, see IMS Version 15 Commands, Volume 3: IMS Component and z/OS® Commands. For details about the Query request, see IMS Version 15 System Programming APIs.

  6. Optionally, after the RECON data set for a system is upgraded, issue the REPAIR.RECON DMBNUM CHECKUP command against a copy of the production RECON data set. This command verifies that all of the data management block (DMB) numbers in the different records in the RECON data set are valid. If no problems are found, run the command once a year.

    If problems are found when you verify the validity of the DMB numbers, issue the REPAIR.RECON DMBNUM UPDATE command against the production RECON data set when access to the RECON data set would be minimal.

    Like the CHANGE.RECON UPGRADE, you can issue the REPAIR.RECON DMBNUM command by using either the IMS 15 DBRC Recovery Control utility (DSPURX00) or the IMS 15 DBRC Command API request.

  7. When you are sure that a fallback to a previous IMS version is unnecessary and all systems that access the RECON data set are at an IMS 15 level, you can update the MINVERS value. Before you issue the CHANGE.RECON MINVERS( '15.1') command, read Minimum version value in the RECON data set to understand the ramifications involved in falling back to a previous version.

After you set the MINVERS level for an IMS system, system signon fails for earlier versions of IMS for online environments. All other jobs accessing the RECON data set fail DBRC initialization if the version of IMS used is lower than the MINVERS level.