Defining an IRLM for sysplex data sharing

If you are implementing a sysplex data-sharing environment, you must define the data-sharing group to which IRLM belongs, the lock structure to be used by that group, and the maximum number of users in that group.

Defining the data-sharing group

For an IRLM to belong to a data-sharing group, you must specify the name of the data-sharing group and the name of the lock structure in the IRLM startup procedure. All IRLMs in this group can share the same data. Each IRLM in the group must:

  • Have a unique IRLMID
  • Specify the same data-sharing group name using the GROUP parameter
  • Specify the same lock structure using the LOCKTAB parameter
Note: The GROUP parameter in the IRLM startup procedure is identical to the IRLMGRP parameter that is used in the START irlmproc command.

Although you can specify these definitions on the IRLM startup procedure, the recommended method is to define them using the CFNAMES control statement. The CFNAMES control statement defines the data-sharing group for a sysplex data-sharing environment. If you do not use the CFNAMES control statement, the lock structure name is pulled from the IRLM startup procedure.

Note: If you use the CFNAMES control statement to define the lock structure name, the LOCKTAB parameter is ignored.

Defining the lock structure

Each IRLM participating in a sysplex data-sharing group (specifying the same z/OS® cross-system coupling facility name on the GROUP=IRLMDS parameter) must specify the same lock structure. You can specify the lock structure name by using the LOCKTAB parameter or the CFNAMES control statement in IMS PROCLIB DFSVSMxx member.

Defining the number of users in a data-sharing group

You must specify a maximum number of users for the data-sharing group. You do this by specifying a value from 2 to 32 on the MAXUSRS parameter.