VOLSEL parameter for DASDPOOL

The VOLSEL parameter specifies the type of volume selection to be performed (SRM, BESTFIT, CRITDSN, DPO, HISTDPO, MAXSPACE, or PERCENT), allowing significant control over the selection of the volume within the pool. VOLSEL is not required, and the default is SRM. The VOLSEL parameter takes effect only if at least one pool has been assigned.

Related topic

Using-Allocation-functions

VOLSEL options are described as follows:

  • SRM specifies the z/OS System Resource Manager (SRM) will select the volume in the DASDPOOL-assigned pool or pools.

    Important

    This option provides the best allocation performance and BMC Software recommends using the SRM option when selecting volumes from a large pool of volumes.

  • BESTFIT selects the volume with the smallest contiguous extent that satisfies the primary allocation.

    For allocations on extended address volumes (EAVs), the available extents on the entire volume will be used for data sets that are eligible to use Extended-Addressing Space (EAS); for all other data sets, the allocation will use the available extents in the Base-Addressing Space (BAS).

  • CRITDSN controls allocations by specifying data sets that should not reside on the same volume.

    Warning

    CRITDSN is resource intensive and should be used only for a small list of critical data sets. It should not be used without considering the system impact.

  • DPO specifies volume selection based on performance statistics accumulated by BMC AMI Storage.

  • HISTDPO specifies volume selection based on historical volume performance.

    Important

    HISTDPO requires more resources than normal allocations.

  • MAXSPACE specifies that the volume with the largest single contiguous extent should be selected.

    For allocations on extended address volumes (EAVs), the available extents on the entire volume will be used for data sets that are eligible to use Extended-Addressing Space (EAS); for all other data sets, the allocation will use the available extents in the Base-Addressing Space (BAS).

  • PERCENT specifies that the volume with the largest percentage of free space should be selected.

    For allocations on extended address volumes (EAVs), the available extents on the entire volume will be used for data sets that are eligible to use Extended-Addressing Space (EAS); for all other data sets, the allocation will use the available extents in the Base-Addressing Space (BAS).



 

Tip: For faster searching, add an asterisk to the end of your partial query. Example: cert*