Idle Space Release › About Idle Space Release › Restrictions

Restrictions

• System temporary data set names
• SYSCTLG data sets
• Model DSCBs
• Checkpoint data sets
• CA Disk Archive data sets
• Key range VSAM data sets
• VSAM data sets with greater than 12 extents
• RRDS VSAM type data sets
• LDS
• KSDS data sets with embedded indexes
• PSE

Data sets with the high level qualifier of SYS1 are bypassed by default. To select these data sets, use sysparm RLSESYS1. Unmovable data sets and empty data sets are selected by default using the DSCL selection criteria. To prevent space from being released from unmovable data sets, use RLSEUNMVy. For more information, see RLSEUNMVy in the Systems Guide or see UNMOVE -- Unmovable attribute (yes/no) in DMS PROC.

Release processing releases idle space from both empty non-VSAM and VSAM data sets. If you allocate space for data sets in one job, and then load data into them in a second job, do not release space from empty non-VSAM data sets. If you select the data bases for processing, each is reduced to the minimum allocation based on its type. That is, either a one-track, a one-cylinder, or a one-MCU data set (reduction to zero tracks that are allocated is not done).

Empty VSAM data sets have a HURBA (High Used Relative Byte Address) of zero. CA Disk uses the HURBA to calculate how much space to release. For space release, CA Disk calculates the HURBA as if equal to the number of bytes in the Control Area. Exclude from processing those data sets, such as SYS HASPACE, that appears empty or over allocated but are not. Use the data set name or volume exclusion lists to exclude these data sets.

For multivolume, non-VSAM data sets, idle space is only released if the idle space is on the last volume. and only if the physical and logical last volumes are the same. For example, if four volumes have data and volume 4 is the logical last volume, then any idle space on volume 4 is released. If only volume 1 and volume 2 have data, then volume 2 is the logical last volume. The idle space is not released, because volume 2 is not the last physical volume. FMT1/8 and DSCB operating system limitations for multi-volume data sets cause this scenario.

Percentage calculations are bypassed because they are based on data set space by volume and would be incorrect. All idle space is released.