Usage notes for SPACSQTY used with Allocation

For compatibility with earlier BMC AMI Storage releases, PQTY and SQTY are assumed to be in kilobytes if ALCTYPE is not coded. The resulting allocation is calculated in average blocks based on the AVL parameter.

ALCTYPE applies to both primary and secondary space quantities. If, for example, PQTY and ALCTYPE are set for an allocation, ALCTYPE is also assigned to the secondary allocation.

The ISPF data set information display in functions 3.4 and 3.2 do not always give the correct values for secondary space in blocks, particularly when the data set is allocated without a block size. The information that is provided by IEHLIST is correct, however.

In general, extent size can be controlled by several allocation functions in either of the following situations:

• At least one of the eligible volumes contains an extent that is large enough to satisfy the requested size.
• SPACSWIR is active, and the eligible volumes do not contain an extent that is large enough to satisfy the requested size.

The BMC AMI Storage functions are as follows:

• SPACSQTY adds or overrides requested space on new allocations.
• SPACPRIM reduces the size of the primary extent if the requested value cannot be found.
• SPACSWIR reduces the size of the first allocation on an added volume if the requested value cannot be found.

• SPACVOLA adds a volume when z/OS encounters an end-of-volume condition.If allocation amounts are specified at the data component level for a newly defined VSAM data set, SPACSQTY will apply any space changes at the data component level. Otherwise, SPACSQTY will apply space changes at the cluster level. For a KSDS VSAM data set, all IBM algorithms for allocating space to the DATA and INDEX components will apply thereafter.

  Warning

  Important

  SPACSQTY has no impact on INDEX space usage for newly defined VSAM KSDS data sets when allocation amounts are specified at the INDEX component level.

IBM APAR II14047 recommends that OEM products not alter space requests for sort work data sets. BMC AMI Storage does not invoke SPACSQTY for a sort work data set that is dynamically allocated. If you should encounter any problems from SPACSQTY altering space on a JCL-defined sort work data set, please contact BMC Customer Support and exclude sort work data sets from SPACSQTY.

You can achieve this exclusion in the filter list by specifying:

To use the LIKE parameter in JCL

When a dataset is allocated using a model dataset (specifying LIKE parameter in JCL), without REPLACE=YES defined to the SET statement of a SPACSQTY rule, SMS allocates the dataset using the space attributes of the model dataset.

Coding REPLACE=YES in the SET statement ensures the datasets are created by SMS with space attributes defined in the SPACSQTY rule.           

The SPACSQTY rule might override the LIKE parameter in certain circumstances even if REPLACE=YES is not coded. For example, if there are no primary and secondary space allocations in the model. To ensure that the SPACSQTY rule overrides the LIKE parameter, you must code REPLACE=YES.