I've encountered a couple situations related to this recently. The Tivoli Enterprise Portal Server requires a database to store screens and various other information for Portal usage. In most shops the Tivoli Enterprise Portal Server (the TEPS) is installed using DB2. In DB2 there is a database called TEPS that contains this information.
Like with any database, it is a good idea to have a process in place to back up the TEPS database. What do you lose if you lose the TEPS database? Well, you can lose your custom workspaces, along with a lot of other customized information and settings. What happens if the server group decides to upgrade your TEPS server and does a complete re-install of DB2? Depending upon how it's done if you don't have a good backup of your TEPS database you may lose valuable customization and information.
How can you backup the TEPS database? There is a DB2 line command option to invoke the BACKUP command. Here's a link to the documentation for the BACKUP command:
Note the database you would be backing up is called TEPS.