Remove the DAS by issuing the /opt/IBM/db2/V8.1/instance/dasdrop command as root.
Remove the instance by issuing the /opt/IBM/db2/V8.1/instance/db2idrop db2 instancecommand as root, where db2 instance refers to the actual instance you want to drop (for example, /opt/IBM/db2/V8.1/instance/db2idrop db2inst1).
Mount the DB2 UDB installation CD and run the /mnt/cdrom/db2_deinstall command as root. This will remove DB2 UDB from your system.
Remove the users that were created during the installation of DB2 UDB ESE by entering these commands as root:
userdel -r db2inst1 userdel -r dasusr1 userdel -r db2fenc1
Optionally, you can remove IBM's version of the Java 2 package that DB2 UDB installs:
rpm -e IBMJava2-SDK