You can make it circular logging and you can set the configuration parameter logretain = off. You cannot make online backups after you set this. You can also specify the number of primary log and secondary log files to be used too.
Could you also let us know, what operation you did, when you started getting the "transaction log full" error? Did you also check out the disk space / log file folder size too?
Db2 requires logging to perform tasks. You cannot eliminate logs, but you can make it circular type. To make it circular, go to the control center, right click on the database, choose configure database logging and follow the instructions in the wizard.
I think you are using the circular logging in your shop. To overcome the message of getting the " Transaction full" you commit regularly, it would solve the issue. If it persist try to increase the log size .