Tablespace definition information (Duplicate Needs RReview)

The size of database managed containers (DMS) must be available to create new tablespace containers with sufficient space. Backup Object Manager keeps information about all tablespaces of a database that is backed up for every backup image on IBM Storage Protect™. The following information is collected for each tablespace:

• The ID and name of the tablespace.
• Whether the tablespace type is system (SMS) or database managed (DMS).
• Whether the tablespace is managed by automatic storage.
• The page size in bytes.
• The extent size in pages.
• The number of pages used.
• The tablespace containers that are used for the tablespace:
  • The ID of the tablespace container.
  • The name of the tablespace container (the directory that contains an SMS container or the file that contains a DMS container).
  • Whether the tablespace container type is a database managed container that is stored in a file or on a raw device.
  • For DMS tablespaces, the total number of pages that are stored in the container.

This information about the physical database layout is referred to as the Tablespace Definition Information (TDI) and is stored along with the production data. The TDI is required for Backup Object Manager redirected restore operations. A TDI image is identified with its corresponding DB2® backup by the combination of DB2 instance name, database alias, database node number, and the timestamp of the backup as shown here:

DB2 instance-DB2 alias-DB2 node number-timestamp.tdi

The TDI is stored in ASCII format to allow for read and edit usability. For example, the number of used pages that are recorded in the TDI image can help identify the correct sizes to request when resizing containers. Backup Object Manager also calculates the number of total pages and used pages from the data that is stored for each tablespace container. Editing might be necessary when you request a redirected restore in batch mode.