List structure parameters

The list structure parameters specify the attributes that are used only for initial allocation of the data tables list structure for a for a coupling facility data table (CFDT) pool. Initial allocation occurs the first time a server is started for the CFDT pool.

The list structure parameters are as follows:
MAXTABLES={1000|number}
Specifies the maximum number of data lists to be reserved when the structure is allocated, which determines the maximum number of tables that can be stored in the structure. This parameter also determines how many list headers are defined when the structure is created.
Specify a large enough number to handle all your data tables, but not so large that unused preallocated list headers use a large amount of coupling facility storage.

You cannot change this number without reallocating the structure, which means first deleting the existing structure (see Deleting or emptying coupling facility data table pools). Therefore, if the structure is being allocated at less than its maximum size, the value here should be based on the maximum possible size of the structure rather than its initial size.

This parameter corresponds to the Maximum number of tables value in the CFSizer tool (see Storage calculations for coupling facility data tables).

This parameter is valid only at server initialization and is used only when the structure is first allocated. The valid range is from 1 to 999999.

You can abbreviate this keyword to MAXT.

Note: In addition to the data lists defined by MAXTABLES there are control lists used internally by CICS® so the total number of lists is greater than the number specified in MAXTABLES.
POOLSIZE={0|number{K|M|G}}
Specifies the initial amount of coupling facility storage to be allocated for the pool list structure, expressed as kilobytes (n K), megabytes (n M) or gigabytes (n G).

Usually, you can omit this parameter and specify the structure size by using the INITSIZE parameter in the coupling facility resource manager (CFRM) policy. However, this parameter can be useful if the structure is reallocated or reloaded but the CFRM policy has not been updated to reflect the required size.

0
The special value 0 means that the server obtains an initial allocation using the parameters specified in the CFRM policy. If the CFRM policy specifies an INITSIZE value for the structure, this determines the initial allocation. Otherwise, the CFRM SIZE value (the maximum size of the structure) is allocated.
number
A non-zero value specifies an initial amount of storage to be allocated, overriding the INITSIZE parameter in the CFRM policy. This value is rounded up by MVS to the next storage increment for the coupling facility level (CFLEVEL). For example, for CFLEVEL 16, the value is rounded up to the nearest 1 MB.

The value must be less than the CFRM SIZE parameter, otherwise the value of POOLSIZE is ignored and the initial allocation uses the parameters specified in the CFRM policy.

The valid range is from 0 to 16777215M. However, you must specify a value that is less than the maximum size of a structure in z/OS®, otherwise a z/OS error occurs. For more details, see the information about CFRM parameters in z/OS MVS Setting Up a Sysplex.

This parameter is valid only at server initialization and is used only when the structure is first allocated.