Warn about 4GB-limited space allocations nearing the 4GB limit (VSAM_4GB_WARN_MSG)

The VSAM_4GB_WARN_MSG function will display a warning message when a 4GB-limited, non-extended addressability data sets is extended to a size approaching the 4GB limit for the data set.

Syntax

VSAM_4GB_WARN_MSG=ENABLE|DISABLE

Operands

ENABLE: Issue a warning message when a data set approaches the 4GB limit.
DISABLE: Do not issue a warning message when a data set approaches the 4GB limit.

Default

DISABLE

Environments

ALLOCATE, EXTEND

Usage and processing considerations

This function is supported for all VSAM data set record organizations for all data sets which do not specify the Extended Addressability attribute in the data set’s associated SMS Data Class. For those data sets for which it is not supported the function is ignored.

For supported data sets, following an extend for secondary allocations and primary allocations on a candidate volume a check will be made on the size of the data set as a percentage of the maximum size of 4GB. If the data set is at or above this calculated percentage a warning message will be issued. The percentage at which the message will be issued is specified in the VSAM_4GB_WARN_MSG_PCT function.

This function will be performed for supported data sets following any non-initial extent added or adjusted in size by any Advanced Allocation Management function as well as any secondary allocation extend which is intercepted by Advanced Allocation Management but not otherwise handled.

Related keywords

VSAM_4GB_EXT_REDUCE, VSAM_4GB_WARN_MSG_PCT

Example

In the following example, VSAM_4GB_WARN_MSG=ENABLE specifies that the VSAM_4GB_WARN_MSG function is enabled.

* RULE DEFINITIONS
*
DEFAULTS 
 . 
 .
EXCLUDE JOBNAME=ABCJOB1    * Item to exclude from processing
INCLUDE JOBNAME=ABCJOB*    * Item to include in processing
VSAM_4GB_WARN_MSG=ENABLE   * Enable 4GB limit warning message

The EXCLUDE keyword specifies the selection criteria that are to be excluded from Advanced Allocation Management processing. In the example, jobs that have a job name of ABCJOB1 are excluded from Advanced Allocation Management processing. If Advanced Allocation Management encounters an extent allocation for a data set in a job that has a job name of ABCJOB1 and that allocation would cause the size of the associated data set to near 4GB in size, Advanced Allocation Management would not issue a warning message for that extent.

However, if Advanced Allocation Management encounters a job that has a job name that starts with ABCJOB other than ABCJOB1, it would issue a warning message following an extend that would cause the size of the data set to near 4GB in size as directed by the VSAM_4GB_WARN_MSG keyword because the INCLUDE statement specifies that jobs with job names that begin with ABCJOB are to be included in Advanced Allocation Management processing.