Troubleshooting
Problem
You have mirror tasks (CSMI) that are not ending after a syncpoint in your CICS Transaction Server for z/OS (CICS TS) region. CICS reaches the maximum number of tasks (MXT limit) because of the number of CSMI tasks in the region.
Cause
Coding of DFHSIT parameters MROFSE=YES and MROLRM=YES prevents the CSMI transaction from ending sessions in the file owning region (FOR).
Diagnosing The Problem
When you code MROFSE=YES in the application owning region (AOR) and MROLRM=YES in the file owning region (FOR), CICS will extend the retention of both the CSMI task and the session until the end of the task. See the CICS information center for more information on Long-running mirror tasks:
Do not specify MROFSE=YES in the front-end region when long-running tasks might be used to function-ship requests, because a SEND session is unavailable for allocation to other tasks when unused. If you specify MROFSE=YES you might prevent the connection from being released, when contact has been lost with the back-end region, until the task ends or issues a function-shipped request.
Resolving The Problem
Set MROFSE to NO in the AOR. If you want to have the performance benefits of using long running mirrors, then investigate why the application is not completing, causing the FOR to reach max task with CSMI transactions.
Product Synonym
CICS/TS CICS TS CICS Transaction Server
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Document Information
Modified date:
05 January 2026
UID
swg21199208