Recover unused disk space (SPACE_RELEASE)

The SPACE_RELEASE function increases available space for other tasks in the system by automatically releasing unused space when a data set is closed.

The SPACE_RELEASE keyword specifies whether to release unused space for a data set during unallocation and, if so, whether to release it only after a secondary extent was allocated.

Syntax

Read syntax diagramSkip visual syntax diagramSPACE_RELEASE=DISABLEENABLESECONDARY

SPACE_RELEASE=ENABLE|DISABLE|SECONDARY

Operands

ENABLE
Release unused space.
DISABLE
Do not release unused space.
SECONDARY
Release unused space only if a secondary extent was allocated. (Space is released if a secondary extent exists.)

Default

DISABLE

Environments

UNALLOCATE

Usage and processing considerations

  • SPACE_RELEASE is only applicable to new or existing physical sequential data sets.
  • The SPACE_RELEASE function is independent of the RLSE subparameter. It does not matter if you specify RLSE in the JCL. Advanced Allocation Management performs the SPACE_RELEASE function, if specified to do so within the rule definitions.
  • Because Advanced Allocation Management causes space release to occur, OS/390® or z/OS® restrictions apply.

Example: SPACE_RELEASE=DISABLE

In the following example, SPACE_RELEASE is set to DISABLE; therefore, Advanced Allocation Management does not release space: 

SPACE_RELEASE=DISABLE

Example: SPACE_RELEASE=ENABLE

In the following example, SPACE_RELEASE=ENABLE specifies that the SPACE_RELEASE function is enabled:

 * RULE DEFINITIONS                  
 DEFAULTS         
 *                                   
INCLUDE  JOBNAME=ABCDJOB             * Item to include in processing
         DDNAME=DD1                  * Item to include in processing
         SPACE_RELEASE=ENABLE        * Function to invoke

Note the following items:

The INCLUDE keyword specifies the following selection criteria:

  • JOBNAME=ABCDJOB specifies that jobs that have a job name of ABCDJOB are to be included in Advanced Allocation Management processing.
  • DDNAME=DD1 specifies that jobs with a DDNAME of DD1 are to be included in Advanced Allocation Management processing.

SPACE_RELEASE=ENABLE specifies that Advanced Allocation Management should automatically release unused space when a data set is closed.

Therefore, if Advanced Allocation Management encounters a job that has a job name of ABCDJOB and a DDNAME of DD1, it automatically releases unused space when a data set is closed.

A job that has a job name that does not match the job name selection criteria of ABCDJOB does not have space that is released in this manner.