Defining a list structure for a named counter server

Define one or more coupling facility list structures for the named counter facility, where each list structure represents a pool of named counters. Each named counter pool is accessed through a cross-memory server region.

Before you begin

A coupling facility structure contains both stored data and the information needed to manage and access that data, in a similar way to a key-sequenced data set. The amount of internal control information depends on the level of functionality and performance of the coupling facility control code for the current coupling facility level (CFLEVEL), and might increase for a higher CFLEVEL. Ensure that you consider storage requirements for your list structures. For more information, see Named counter list structure storage.

About this task

Define the structure in the current coupling facility resource management (CFRM) policy by using the utility IXCMIAPU. For an example of this utility, see member IXCCFRMP in the SYS1.SAMPLIB library (see Administrative data utility for CFRM policy data in z/OS MVS Setting Up a Sysplex).

Procedure

Specify the name of the list structure.
The name is formed by adding the prefix DFHNCLS_ to your chosen pool name, giving DFHNCLS_poolname.
Specify the size of the list structure.
You can allocate an initial and maximum size using the INITSIZE and SIZE parameters in the CRFM policy definition. For an accurate estimate of storage requirements, use the IBM® CFSizer tool. See CFSizer.
Specify the preference list of coupling facilities in which the policy can be stored.
An example definition of a coupling facility list structure for named counters is as follows:
```
STRUCTURE  NAME(DFHNCLS_PRODNC1)
   SIZE(2048)
   INITSIZE(1024)
   PREFLIST(FACIL01,FACIL02)    
```
When you have updated the CFRM new policy with the new structure definition, activate the policy using the following MVS™ command:
```
SETXCF START,POLICY,POLNAME=policyname,TYPE=CFRM.
```

Results

You have defined the CFRM policy statements for a list structure. This action does not create a list structure. The structure is created the first time an attempt is made to connect to it, which occurs when the first named counter server that refers to the corresponding pool is started.

Before you start the named counter server, ensure that you have defined and started the authorized cross-memory (AXM) server environment (see Defining and starting AXM system services).