DB2 Version 9.7 for Linux, UNIX, and Windows

Altering DMS table spaces

For DMS table spaces, you can add, extend, rebalance, resize, drop, or reduce containers.

Adding DMS containers
You can increase the size of a DMS table space (that is, one created with the MANAGED BY DATABASE clause) by adding one or more containers to the table space.
Dropping DMS containers
With a DMS table space, you can drop a container from the table space using the ALTER TABLESPACE statement.
Resizing DMS containers
Containers in a database managed (DMS) table space can be resized as storage needs change. If you use the auto-resize capabilities for DMS containers, the database manager handles this for you. If you did not enable the auto-resize option, you can also make adjustments manually.
Rebalancing DMS containers
The process of rebalancing involves moving table space extents from one location to another, and it is done in an attempt to keep data striped within the table space. You typically rebalance a table space when adding storage paths to or dropping storage paths from a database.
Monitoring a table space rebalance operation
You can use the SNAP_GET_TBSP_PART_V91 table function to monitor the progress of rebalance operations on a database.
Reclaiming unused storage in DMS table spaces
You can reclaim unused storage in a DMS table space by telling the database manager to consolidate in-use extents lower in the table space. This also has the effect of lowering the high water mark. To reduce the container sizes in a DMS table space requires a separate REDUCE operation must also be performed.
Prefetch size adjustment when adding or dropping containers
The default size for all prefetches from disk is set automatically for any table spaces created using DB2® versions 8.2 and later. This means that the database manager calculates a suitable prefetch size based on several factors, including the extent size, the number of containers in your table space, and the properties of your storage devices.
Converting table spaces to use automatic storage
You can convert some or all of your database-managed space (DMS) table spaces in a database to use automatic storage. Using automatic storage simplifies your storage management tasks.