Using the multi-tiered storage group function

Before you begin: Be familiar with conventional volume selection for allocation, which is described in SMS volume selection for data set allocation.

You can specify Multi-Tiered SG (Y) in the storage class to enable the multi-tiered storage group function. When you specify this function, SMS allocates to enabled pool storage groups in the order they are specified in the ACS storage group selection routines.

Example: Multi-Tiered SG (Y) is specified in the storage class. An ACS storage group routine assigns the following three similar storage groups:

SET &STORGRP = 'SG1', 'SG2', 'SG3'

Result: SMS selects the enabled volumes that are below the high threshold in SG1 before selecting volumes in the SG2 storage groups that are listed second, third, and so forth, can also be used depending on the status of the underlying volumes when:

All SG1 enabled volumes exceed high threshold, then SMS selects the enabled volumes in SG2.
All SG1 and SG2 enabled volumes exceed the high threshold, SMS selects the enabled volumes in SG3.
All enabled volumes exceed the high threshold, SMS selects the quiesced volumes in the same storage group order.

Only volumes that reside in the first storage group assigned by the ACS routines (SG1 in the example) are eligible for the primary list.