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