IBM SC34-7012-01 manual Model log streams for CICS general logs, What to do next

2.Define a general log stream for forward recovery data. If you do not define a general log stream, CICS attempts to create a log stream dynamically. See “Model log streams for CICS general logs” for details.

3.Decide how you want to merge forward recovery data from different CICS regions into one or more log streams. See “Merging data on shared general log streams” on page 118 for details.

What to do next

In the event of physical failure or corruption, restore the most recent backup, and use a forward recovery utility such as CICS VSAM Recovery to reapply updates.

To recover from a storage failure, first restore the most recent backup to a new data set. Then use a forward recovery utility, such as CICS VSAM Recovery (CICSVR), to apply all the updates that were written to a forward recovery log stream after the backup date.

Model log streams for CICS general logs

If CICS fails to connect to a general log stream because it has not been defined, CICS attempts to have it created dynamically.

To create a log stream dynamically, CICS must specify to the MVS system logger all the log stream attributes needed for the new log stream. To determine these otherwise unknown attributes, CICS requests the MVS system logger to create the log stream using attributes of an existing model log stream definition. If you decide to allow CICS to create log streams dynamically, you are responsible for creating the required model log stream definitions to ensure that dynamic creation succeeds.

It is generally worthwhile setting up model log streams only if:

vEach model log stream will be used to create several log streams

vEach log stream created using a model log stream has similar characteristics consistent with the use of the same coupling facility structure

vYou don't know in advance the journal names that will be used by CICS applications.

Otherwise, it is probably less work to define the log streams explicitly using

IXCMIAPU.

The default model log stream names that CICS uses for dynamic creation of a general log stream are of the form LSN_qualifier1.LSN_qualifier2.MODEL where the first and second qualifiers are the CICS region userid and the CICS APPLID, respectively.

Example: If a CICS region, running under userid CICSHA## with APPLID=CICSHAA1, issues a request to create a general log stream that is not defined by a JOURNALMODEL resource definition, CICS specifies CICSHA##.CICSHAA1.MODEL as the model log stream name.

See “Model log streams for CICS system logs” on page 110 for information about using an XLGSTRM global user exit program to modify requests to create a log stream.

Chapter 11. Defining system and general log streams 117