Configuration Best Practices › Practices for Improved Productivity and System Availability › Automate Journal Offload

Automate Journal Offload

Use the Write-to-Operator exit (WTOEXIT) to automate the offloading of a full disk journal file.

Business Value:

This practice avoids processing delays caused when a CA IDMS central version must halt database activity due to a lack of journal space.

Additional Considerations:

A CA IDMS central version uses its disk journal files to record update activity against its database files. Journal information is needed for recovery in case of failures such as system outages or damaged files.

A central version uses at least two and sometimes several disk journal files. When one journal file fills, CA IDMS automatically switches to another journal file. However if all journal files fill, CA IDMS must halt update activity until the ARCHIVE JOURNAL utility is executed to archive the journal data and reclaim space on the journal file. To avoid processing delays, it is critical to run this utility as soon as a central version switches to a new journal file.

CA IDMS switches to another disk journal file when:

• The active disk journal becomes full.
• A DCMT VARY JOURNAL command is issued under the central version.
• An I/O error is detected on the active disk journal file.

When CA IDMS switches to another disk journal file, it writes a DC205003 message to the operator. This message indicates that a swap has occurred and that the previously active journal file needs offloading. Usually an operator must respond to this message by submitting a job to archive the full file. You can eliminate the need for operator intervention and ensure immediate job submission by using a Write-to-Operator exit routine. The WTO exit intercepts and reviews the message to the operator and responds by automatically submitting a job through the internal reader.

During configuration, the source for a sample WTO exit module called WTOEXIT is assembled and linked. The exit looks for DC205003 messages. Each time one is encountered, the exit submits the contents of the file identified by the AJNLJOB DD statement that must be included in your startup JCL. The startup JCL created in Job 2 shows how to use the sample WTOEXIT module.

The module does not have to be named WTOEXIT. To use a different name, assemble and link the sample source from Job 2 using the name of your choice and specify the name as a startup parameter to your central version.

More Information:

For more information about journals, see the CA IDMS Database Administration Guide. For information about the WTOEXIT user exit and sample routines, see the CA IDMS System Operations Guide.