Do the following for both coupling facility and DASD-only log streams to format a primary and alternate LOGR couple data set and define them to the sysplex:

1. Format the primary and alternate LOGR couple data set using the IXCL1DSU utility.

   Format a primary and alternate LOGR couple data set using the IXCL1DSU utility. IBM® recommends they are on different volumes.

   You must provide as input the maximum number of log streams and structure definitions you plan to define. For DASD-only log streams, you will not have structures to define, so do not increase the number of structures for DASD-only log streams. These values were calculated in Plan the system logger configuration.

   It is a good idea to place the primary and alternate LOGR couple data sets on different volumes. This will allow for the latest logger features to be available given the sysplex configuration. See LOGR couple data set versioning — new format levels to understand the supported system logger functional capabilities for the different LOGR couple data set format levels.

   For complete information and examples of using the IXCL1DSU utility, see Format utility for couple data sets.

2. Update the COUPLExx member in SYS1.PARMLIB to identify the LOGR couple data set to the sysplex.
   Add your primary and alternate LOGR couple data set names to the COUPLExx parmlib member. See the following for more information:

   • Defining function couple data sets to MVS for an example of defining the LOGR couple data set in the COUPLExx parmlib member.
   • z/OS MVS Initialization and Tuning Reference for complete the COUPLExx parmlib member.
3. Make the LOGR couple data set available.
   You can use either of the following ways to make the primary and alternate couple data sets available to the sysplex:

   • IPL the system with the primary and alternate LOGR couple data sets defined in the COUPLExx parmlib member.
   • Issue the following SETXCF commands when you want to bring the LOGR couple data sets online without IPLing the system as follows:

     SETXCF COUPLE,TYPE=LOGR,PCOUPLE=(primary_couple_data_set)
     SETXCF COUPLE,TYPE=LOGR,ACOUPLE=(alternate_couple_data_set)

   Either of these methods causes the empty LOGR couple data set to become available on all systems where system logger is installed. After the SETXCF command is entered, you can define structures and log streams in the LOGR policy.

4. Additional Guidance on Handling LOGR Couple Data Sets

   See LOGR couple data set use considerations for guidance on identifying and using an existing LOGR couple data set for use by the sysplex.