LOG_CHECKPOINT_TIMEOUT and LOG_CHECKPOINT_INTERVAL have nothing to do with how often your redo logs switch. See http://technet.oracle.com/docs/produ...recov.htm#9764 , http://technet.oracle.com/docs/produ...0_io.htm#22462 , http://technet.oracle.com/docs/produ...ch190.htm#5517 , http://technet.oracle.com/docs/produ...h189.htm#55753 for details.