Change the staging data set size for coupling facility log streams

If you need to change the staging data set size for a log stream because of a change in conditions or in response to monitoring SMF record 88, note that the staging data sets must actually be deleted and then reallocated in order to change. This is because the staging data set size and other log stream attributes are defined at allocation and remain in effect as follows:

For a log stream defined as STG_DUPLEX(YES) and DUPLEXMODE(UNCOND), until the last connection to the log stream disconnects.
For a log stream defined with STG_DUPLEX(YES) and DUPLEXMODE(COND), while the configuration contains a single point of failure or until the last connection to the log stream disconnects.

To change staging data set size, do the following:

Depending on how the log stream is defined, do one of the following:
- For a log stream defined with STG_DUPLEX(YES) and DUPLEXMODE(UNCOND) or DUPLEXMODE(DRXRC), have all instances of the application on all systems disconnect from the log stream.
- For a log stream defined with STG_DUPLEX(YES) and DUPLEXMODE(COND), either issue a structure rebuild so that the configuration no longer contains a single point of failure or else have all instances of the application on all systems disconnect from the log stream.
Change the STG_SIZE parameter in the LOGR policy either to a new value or the default, to take the system logger defined default.
Alternatively, change the STG_DATACLAS parameter or if an automatic class selection (ACS) routine is used by SMS, then the ACS routine may need to be updated to assign a new SMS data class construct for the log stream staging data sets.
Have all systems reconnect to the log stream.

For example, to change the staging data set size for logrec log streams, you would:

Issue the SETLOGRC DATASET command to disconnect logrec from the log stream and record logrec records in a data set.
Update the STG_SIZE value in the LOGR policy using the IXGINVNT service or the IXCMIAPU utility.
Issue the SETLOGRC LOGSTREAM command to reconnect to and reactivate the logrec log stream.

If the update of the staging data set size does not work, it might be because there are more connectors to the log stream that have not been disconnected. Use the DISPLAY LOGGER,L and DISPLAY LOGGER,C commands with the LSN=name specified, or use the LIST request on the IXCMIAPU utility, to see if there are still connectors. Make sure that all log stream connectors have disconnected, by canceling the job if necessary, before changing the staging data set size in the LOGR policy.