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Overriding the type of start indicator
The operation of the recovery manager's control record can be modified by
running the recovery manager utility program, DFHRMUTL.
About this task
This can set an autostart record that determines the type of start CICS is to
perform, effectively overriding the type of start indicator in the control record. See
the CICS Operations and Utilities Guide for information about using DFHRMUTL to
modify the type of start performed by START=AUTO.
Warm restart
If you shut down a CICS region normally, CICS restarts with a warm restart if you
specify START=AUTO. For a warm start to succeed, CICS needs the information
stored in the CICS catalogs at the previous shutdown, and the information stored
in the system log.
In a warm restart, CICS:
1. Restores the state of the CICS region to the state it was in at completion of the
normal shutdown. All CICS resource definitions are restored from the global
catalog, and the GRPLIST, FCT, and CSD system initialization parameters are
ignored.
CICS also uses information from the warm keypoint in the system log.
2. Reconnects to the system log.
3. Retries any backout-failed and commit-failed units of work.
4. Rebuilds indoubt-failed units of work.
For more information about the warm restart process, see Chapter 5, “CICS warm
restart,” on page 53.
Emergency restart
If a CICS region fails, CICS restarts with an emergency restart if you specify
START=AUTO. An emergency restart is similar to a warm start but with additional
recovery processing for example, to back out any transactions that were in-flight at
the time of failure, and thus free any locks protecting resources.
If the failed CICS region was running with VSAM record-level sharing, SMSVSAM
converts into retained locks any active exclusive locks held by the failed system,
pending the CICS restart. This means that the records are protected from being
updated by any other CICS region in the sysplex. Retained locks also ensure that
other regions trying to access the protected records do not wait on the locks until
the failed region restarts. See the CICS Application Programming Guide for
information about active and retained locks.
For non-RLS data sets (including BDAM data sets), any locks (ENQUEUES) that
were held before the CICS failure are reacquired.
Initialization during emergency restart
Most of CICS initialization following an emergency restart is the same as for a
warm restart, and CICS uses the catalogs and the system log to restore the state of
the CICS region. Then, after the normal initialization process, emergency restart
Chapter 3. Shutdown and restart recovery 35