SMS volume selection for data set allocation

When a data set is created, SMS follows a sequence of steps to place it on a volume. This section describes how SMS selects a volume based on the requirements of a data set. It explains conventional volume selection, striping volume selection and multi-tiered volume selection. Finally, it discusses why volume selection might fail.

Restriction: SMS does not check or verify DASDVOL authorization for data set allocations on SMS-managed volumes. By adding a volume to SMS you are removing it from any active DASDVOL authorizations because DASDVOL access is not verified on SMS-managed volumes. See z/OS Security Server RACF Security Administrator's Guide for further information on DASDVOL authority.

SMS attempts to spread initial allocations evenly across similar volumes and storage groups provided by the ACS storage group selection routine unless you specify Multi-Tiered SG (Y) in the storage class. In that case, SMS performs an allocation using storage groups in the order in which they are specified in the ACS storage group selection routine. For more information, see Using the multi-tiered storage group function.