DFSMS-managed subpooling is a method of dividing these storage groups into pools to improve data set allocation and performance. This functionality is limited to denying volumes outside of an DFSMS-defined pool. Volume selection cannot be directed outside of the data set’s current storage group. If multiple pools are specified, the first pool with sufficient space for the data set is assigned. The first specified pool is the primary pool; all other pools are alternate pools.
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