TSM DB and LOG

Increasing the size of the database

You can increase the size of the database by creating directories and adding them to the database.

The server can use all the space that is available to the drives or file systems where the database directories are located. To ensure that database space is always available, monitor the space in use by the server and the file systems where the directories are located. The maximum supported size of the database is 2 TB.

The QUERY DB command, shown in Monitoring the database and recovery log, displays number of free pages in the table space and the free space available to the database. If the number of free pages are low and there is a lot of free space available, the database allocates additional space. However, if free space is low, it might not be possible to expand the database.

To increase the size of the database, take the following steps:

1. Create one or more database directories. Locate the directories on separate drives or file systems.

2. Issue the EXTEND DBSPACE to add one or more directories to the database. The directories must be accessible to the user ID of the database manager. Locate the directories on different drives or file systems. 

For example, to add two directories to the storage space for the database, issue the following command:

extend dbspace /tsmdb005,/tsmdb006

Reducing the size of the database

If a significant amount of data has been deleted from the database, consider reducing the database size.

1. Create a file containing a list of directories that represent the new directories. For example, dbdirs.txt.

2. Run a full database backup. For example:

backup db devclass=tapeclass type=full

3. Halt the server.

4. Remove the database instance. 

dsmserv removedb TSMDB1

5. Restore the database specifying the file containing the directories to be used. For example:

dsmserv restore db todate=today on=dbdirs.txt

6.Restart the server.

Increasing the size of the active log

If the log is running out of space, the current transaction is rolled back, and the server issues an error message and halts. You cannot restart the server until the active log size is increased.

To increase the size of the active log while the server is halted, complete the following steps: 

1. Issue the DSMSERV DISPLAY LOG offline utility to display the size of the active log. 

2. Ensure that the location for the active log has enough space for the increased log size. If a log mirror exists, its location must also have enough space for the increased log size. 

3. Halt the server. 

4. In the dsmserv.opt file, update the ACTIVELOGSIZE server option to the new maximum size of the active log, in megabytes. For example, to change the active log to its maximum size of 128 GB, enter the following server option: 

activelogsize 131072 

5. If you will use a new active log directory, update the directory name specified in the ACTIVELOGDIR server option. The new directory must be empty and must be accessible to the user ID of the database manager. 

6. Restart the server.

Log files of 512 MB are automatically defined until the size specified in the ACTIVELOGSIZE server option is reached. If a log mirror exists, log files are also defined automatically.