DBRC migration and coexistence
DBRC enhancements include changes to the RECON data set format for IMS 15 and support that allows IMS Version 13 and IMS 14 systems to coexist until all of the systems are upgraded to IMS 15.
- The header version indicator is V15R1.
- The default value for MINVERS is set to
13.1
(X'D1'). - The RECON level is set to
15.1
(X'E1'). - The log release level in the PRILOG, SECLOG, PRISLD, SECSLD, PRIOLD, and SECOLD (and interim)
records is set to X'3C', but is listed as
15.1
. - The version and coexistence level in the subsystem record is set to
15.1
(X'E1').
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.
Certain DBRC API requests are enhanced to show the new information that is in the RECON data sets.
- 7.0 for the IMS 15 API.
- 6.0 for the IMS 14 API.
- 5.0 for the IMS Version 13 API.
Coexistence considerations
The INIT.GSG command is not supported in IMS 15. If you try to use this command for IMS 15, the DSP1035I message is issued.
You can use 8GB OSAM HALDB without OLR Support for IMS 15 by configuring the following settings. This support was introduced in IMS 14. With this support, you can define an HALDB database to use up to eight gigabytes of data in its OSAM PHDAM or PHIDAM OSAM data sets.
- Set the MINVERS value to 14.1.
- Set the MINVERS value to 13.1 if the cross DBRC service level ID (CDSLID) value is set to 2. The CDSLID set to 2 indicates that the IMS Version 13 8GB OSAM Support for HALDBS without OLR SPE has been applied to all IMS Version 13 resident libraries (RESLIBS) accessing the RECON data set.
Performance considerations
Before you upgrade a RECON with parallel access active, close the RECON data sets and perform a check for retained locks. The upgrade fails if retain locks exist. The RECON data sets are reopened in LSR mode when parallel access is active. This improves performance by eliminating the need for locking.
Excessive CA/CI splits might delay RECON upgrade.
While the RECON is being upgraded, other jobs wait, which impacts the performance of any DBRC requests.
Before you issue the CHANGE.RECON UPGRADE CHECKUP command against the production RECON data set, issue the command against a copy of the production RECON data set to understand any possible performance issues.
Log record changes
- DSPRCNRC
- DSPRCR1
- DSPLOGRC
- DSPOLDRC
- DSPSSRC
Changes to troubleshooting for IMS
For a list of the messages and codes that are new or changed for this enhancement, see the IMS messages and codes row in the table in Documentation changes.
For a complete list of all of the new, changed, and deleted messages, and abend codes in IMS 15, see Message and code changes in IMS 15.
Changes to commands
The CHANGE.RECON UPGRADE command is changed to upgrade an IMS Version 13 or IMS 14 RECON data set.
For a list of the commands that are new or changed for this enhancement see the IMS commands row in the table in Documentation changes.
Changes to utilities
Batch Backout, Log Recovery and Log Archive utilities can only run on the release which created the log(s). That is, an IMS Version 13 or an IMS 14 Batch Backout utility cannot be used to back out an IMS 15 log.
The Database Recovery utility and the Change Accumulation utility must be run with highest level of logs being used. For example, the IMS 14 utilities may use IMS 14 logs but not IMS 15 logs.
Documentation changes
The following table lists the publications that contain new or changed topics for the New function name enhancement. Publications that are not impacted by this enhancement are not included in the table.
| Publication | Links to topics | ||
|---|---|---|---|
| Release planning |
|
||
| Database administration | |||
| System programming APIs | |||
| IMS messages and codes | DBRC messages | ||
| IMS commands | DBRC commands | ||