IBM SC34-7012-01 manual Dynamic RLS restart

You can do this by specifying START=INITIAL as a system initialization parameter, or by running the recovery manager's utility program (DFHRMUTL) to override the type of start indicator to force an initial start.

See the CICS Operations and Utilities Guide for information about the DFHRMUTL utility program.

Dynamic RLS restart

If a CICS region is connected to an SMSVSAM server when the server fails, CICS continues running, and recovers using a process known as dynamic RLS restart. An SMSVSAM server failure does not cause CICS to fail, and does not affect any resource other than data sets opened in RLS mode.

When an SMSVSAM server fails, any locks for which it was responsible are converted to retained locks by another SMSVSAM server within the sysplex, thus preventing access to the records until the situation has been recovered. CICS detects that the SMSVSAM server has failed the next time it tries to perform an RLS access after the failure, and issues message DFHFC0153. The CICS regions that were using the failed SMSVSAM server defer in-flight transactions by abending units of work that attempt to access RLS, and shunt them when the backouts fail with “RLS is disabled” responses. If a unit of work is attempting to commit its changes and release RLS locks, commit failure processing is invoked when CICS first detects that the SMSVSAM server is not available (see “Commit-failed recovery” on page 83).

RLS mode open requests and RLS mode record access requests issued by new units of work receive error responses from VSAM when the server has failed. The SMSVSAM server normally restarts itself without any manual intervention. After the SMSVSAM server has restarted, it uses the MVS event notification facility (ENF) to notify all the CICS regions within its MVS image that the SMSVSAM server is available again.

CICS performs a dynamic equivalent of emergency restart for the RLS component, and drives backout of the deferred work.

Recovery after the failure of an SMSVSAM server is usually performed automatically by CICS. CICS retries any backout-failed and commit-failed units of work. In addition to retrying those failed as a result of the SMSVSAM server failure, this also provides an opportunity to retry any backout failures for which the cause has now been resolved. Manual intervention is required only if there are units of work which, due to the timing of their failure, were not retried when CICS received the ENF signal. This situation is extremely unlikely, and such units of work can be detected using the INQUIRE UOWDSNFAIL command.

Note that an SMSVSAM server failure causes commit-failed or backout-failed units of work only in the CICS regions registered with the server in the same MVS image. Transactions running in CICS regions in other MVS images within the sysplex are affected only to the extent that they receive LOCKED responses if they try to access records protected by retained locks owned by any CICS regions that were using the failed SMSVSAM server.

Chapter 3. Shutdown and restart recovery 37