Administration Getting Started

Basic Capacity Management

There are a few basic things you can do to manage the capacity of a database. This section describes how to:

• Check the amount of space available in a table space
• Add more space to an existing table space when it starts to get full

Checking Space Available in a Table Space

To check the amount of space available in a DMS table space:

1. From the Control Center, double-click on the Table spaces folder for the database you want to work with. A list of all the table spaces appears in the contents pane.

2. Scroll to the columns entitled Allocated size, Size used, and Percentage used to see details related to the amount of space available in a table space. Space is shown in pages where one page is 4 KB.

You can customize the order of the columns and which columns are displayed by using the Customize Columns push button.

To check the amount of space available in an SMS table space, use the facilities provided by your operating system to monitor space usage and to ensure that available room in the directory for the table space is not exhausted.

Adding More Space To a Table Space

The previous section describes how to check the capacity of a DMS table space. Capacity for a DMS table space is the total size of containers allocated to the table space. When a DMS table space reaches capacity (depending on the usage of the table space, 90% is a possible threshold), you should add more space to it. The database manager will automatically re-balance the tables in the DMS table space across all available containers. During re-balancing, data in the table space remains accessible.

The strategy is different for DMS and SMS table spaces. For a DMS table space that has reached its capacity, you can add another container, as follows:

1. From the Control Center, click mouse button 2 on the table space in the contents pane for which you want to add a container, and select Alter from the pop-up menu. The Alter Table Space window opens.

2. Click on Add. The Add Container window opens.

3. Select the File or Raw device radio button, and complete the fields. See the online help for assistance.

4. Click on OK.

In general, you cannot extend the size of an SMS table space very easily because SMS capacity depends on the space available in the file system and the maximum size of the file supported by the operating system. However, depending on your operating system, you may be able to increase the size of a file system using the operating system facilities. For an SMS table space on a UNIX-based system, you can increase the size of the table spaces by using the appropriate UNIX-based system commands. See the documentation for the UNIX-based system you are running. If the file system containing the SMS table space also contains non-DB2 files, you may be able to move these files to another file system, thus making more room available in the file system for DB2's use. You can also perform a redirected restore which involves restoring a table space into a larger number of containers than it was backed up from. See the Administration Guide for more information about redirected restores. You can perform a redirected restore from the Restore Database notebook (from the database you want to restore, select Restore -> Database from the pop-up menu).

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