The ondblog utility lets you change the logging mode for one or more databases.
The ondblog utility logs its output in the BAR_ACT_LOG file
If you turn on transaction logging for a database, you must create a level-0 backup of all the storage spaces that contain data in the database before the change takes effect.
For more information and examples, see the following topics in the chapter on managing database-logging status in the IBM Informix Administrator's Guide: