You can restart a DB2 instance from the GUI. You must have a UNIX user name and password.
To restart a DB2 instance
Access the DB2 Start Instance wizard.
Verify the DB2 instance information, such as the instance name, home directory, and instance owner Then, click Next to continue.
At the confirmation prompt, click Yes to confirm that you want to start the database.
If the DB2 instance was successfully restarted, you will receive a confirmation message. Click OK to continue.