Understanding MVS™ log streams
Coupling facility log streams reside in the coupling facility and in either a data space in the IXGLOGR address space or in staging data sets. DASD-only log streams reside in a data space in the IXGLOGR address space and in staging data sets.
All log streams that are needed by CICS® must be defined to the MVS™ system logger before CICS® can use them. You can either define log streams explicitly, or you can let CICS® create them dynamically when they are first used. To enable CICS® to create log streams dynamically, you first define model log streams to the MVS™ system logger. To define explicit log streams and model log streams, use the MVS™ IXCMIAPU utility.
For information about the coupling facility and defining log structures, see z/OS® MVS™ Setting Up a Sysplex. For information about defining coupling facility log structures and MVS™ log streams for use by CICS® Transaction Server, see CICS® System Definition Guide.