Updating the CFRM policy

Specify ALLOWAUTOALT(YES) to request that the structure be eligible for system-initiated alter processing. For structure alter processing to be started for a structure, alter must be permitted (see the SETXCF MODIFY command) and the exploiter must also allow alter. The ALLOWAUTOALT specification affects the default value for MINSIZE.

The ALLOWAUTOALT specification takes effect immediately when the updated CFRM policy is activated.

ALLOWAUTOALT(NO) is the default value.

The value you assign to the FULLTHRESHOLD parameter is used by both Structure Full Monitoring and system-initiated alter processing. The value is specified as a percentage and represents a percent full threshold in terms of coupling facility structure objects. See Monitoring structure utilization. If a value of zero is assigned to FULLTHRESHOLD, neither structure full monitoring nor automatic altering of the structure will occur. If a value other than zero is specified or defaulted to, the value is used as the percent full threshold for structure full monitoring as well as being used by system-initiated alter processing to determine how to alter the structure if the exploiter allows alter. If the exploiter does not allow alter, the ALLOWAUTOALT specification is ignored and a non-zero value for FULLTHRESHOLD is used only by Structure Full Monitoring to alert the installation.

The FULLTHRESHOLD specification takes effect immediately when the updated CFRM policy is activated.

80% is the default value for FULLTHRESHOLD.

The value you assign to MINSIZE specifies the smallest size to which the structure can ever be altered, either as a result of system-initiated alter or any alter process (operator command or programming interface). This value also serves as a minimum bound for the structure size on all structure allocation requests (including connect and rebuild connect) with the following exception. During system-managed rebuild, new structure allocation may result in the structure being allocated with a size smaller than the value specified or defaulted to for MINSIZE. See How MVS initially allocates the structure for information about structure allocation during system-managed rebuild.

The MINSIZE value must be less than or equal to the INITSIZE value, or less than or equal to the SIZE value if INITSIZE is not specified. If ALLOWAUTOALT(YES) is specified and MINSIZE is not specified, the system will use a value of 75% of INITSIZE, or 75% of SIZE if INITSIZE is not specified, as the MINSIZE value. Otherwise, if ALLOWAUTOALT(NO) is specified or defaulted to and MINSIZE is not specified, the system will use a value of zero for MINSIZE.

Note that in order for the MINSIZE value to take effect in the sysplex, a newly-activated CFRM policy will remain pending until any allocated structures with a MINSIZE value other than zero have been rebuilt to reflect the policy change. (For structures that are not allocated, the policy change can take effect immediately.) For those allocated structures, you are required to either deallocate or reallocate the structure or issue SETXCF START,REBUILD,STRNAME=strname before the policy change takes effect for the structure.