A storage group is a named set of storage paths where data can be stored. Storage groups are configured to represent different classes of storage available to your database system. You can assign table spaces to the storage group that best suits the data. Only automatic storage table spaces use storage groups.
A table space can be associated with only one storage group, but a storage group can have multiple table space associations. To manage storage group objects you can use the CREATE STOGROUP, ALTER STOGROUP, RENAME STOGROUP, DROP and COMMENT statements.
With the table partitioning feature, you can place table data in multiple table spaces. Using this feature, storage groups can store a subset of table data on fast storage while the remainder of the data is on one or more layers of slower storage. Use storage groups to support multi-temperature storage which prioritizes data based on classes of storage. For example, you can create storage groups that map to the different tiers of storage in your database system. Then the defined table spaces are associated with these storage groups.