Storage management has been improved

A major advance in DB2® V10.1 is the ability to create storage groups, which are groups of storage paths. A storage group contains storage paths with similar characteristics.

Some critical attributes of the underlying storage to consider when creating or altering a storage group are available storage capacity, latency, data transfer rates, and the degree of RAID protection.

These storage groups can be used to create different classes of storage (multi-temperature storage classes) where frequently accessed (or hot) data is stored in storage paths residing on fast storage, while infrequently accessed (or cold) data is stored in storage paths residing on slower, less expensive storage.

After you create storage groups that map to the different classes of storage in your database management system, you can assign automatic storage table spaces to those storage groups, based on which table spaces have hot or cold data. You can use storage groups to physically partition table spaces managed by automatic storage. You can dynamically reassign a table space to a different storage group by using the ALTER TABLESPACE statement with the USING STOGROUP option.

A database-managed table space can be converted to an automatic storage table space by executing an ALTER TABLESPACE statement and specifying the MANAGED BY AUTOMATIC STORAGE clause on the table space. Note that after this is done, it is necessary to perform a rebalance operation on the table space by executing an ALTER TABLESPACE statement and specifying the REBALANCE clause on the table space. In V10.1, the rebalance operation is enhanced to manually SUSPEND and RESUME a rebalance operation during performance sensitive periods.

You can take further advantage of organizing your data into storage groups by configuring DB2 workload manager (WLM) to prioritize activities based on the priority of the data being accessed.

The ADMIN_GET_STORAGE_PATHS table function can be used to get the list of automatic storage paths for each database storage group, including file system information for each storage path. Other table functions that have been added or modified to support the monitoring of storage groups include: MON_GET_REBALANCE_STATUS, MON_GET_TABLESPACE and MON_GET_CONTAINER.