When planning to share system commands among different systems, ask yourself the following questions:

1. What resources are good candidates for sharing?

   If your goal is to greatly simplify your operating environment, the answer is: As many as possible! If two or more systems require different names for a resource, chances are that you can use a single system symbol to represent the characters in the name that must be unique. If you have one "skeleton" that represents the unique names, you have one convenient place to maintain the resource definition. If you follow the same process with all commands that require unique values, you can view a multisystem environment as a single system image with one point of control.

   Be aware that there are also reasons why you might not want to share certain commands. Perhaps the release level of MVS™ prevents you from using a resource on a particular system; or perhaps one or more systems do not require a particular resource. Whatever the case, your installation must examine the commands that are issued frequently and determine the extent to which they can be shared.

2. What commands support system symbols?
   All z/OS® commands support system symbols, with the exception of:

   • The LOGON command
   • The VARY CN(*),ACTIVATE form of the VARY command (all other forms of VARY support system symbols).
3. Do I want a job to have different names on each system where it runs?

   If a job runs on two or more systems in a multisystem environment, IBM® recommends that you use different jobnames for each instance of the job. Different jobnames allow you to easily identify the system on which a job runs.

   The best way to explain how to use one command to start jobs with different names on different systems is through an example. Suppose your installation is to start Customer Information Control System (CICS®) on each system in a sysplex and assign a different jobname to each instance of CICS. First your installation establishes a consistent naming convention for the instances of CICS. For example, the jobname for each instance of CICS always begins with the characters CICS and ends with the last four characters of the system name.

   You can specify the &SYSNAME system symbol in the START command and route the command to all systems that require CICS:

    ROUTE *ALL S CICS,JOBNAME=CICS&SYSNAME.,...

   Each system substitutes the text it has defined to &SYSNAME into the command text. Assuming that you route the START CICS command to two systems named SYS1 and SYS2, the following commands result:

      S CICS,JOBNAME=CICSSYS1,...
      S CICS,JOBNAME=CICSSYS2,...

   Your installation can also specify system symbols in commands that are entered at system initialization using the COMMNDxx parmlib member. See the description of the COMMNDxx parmlib member in z/OS MVS Initialization and Tuning Reference for information about how the system processes system symbols in COMMNDxx.