Redo Log Tuning Advisory and Automatic Checkpoint Tuning are new features introduced in Oracle 10G, if you are on 10g you may benefit from these features.
The size of the redo log files can influence performance, because the behavior of the database writer and archiver processes depend on the redo log sizes. Generally, larger redo log files provide better performance, however it must balanced out with the expected recovery time. Undersized log files increase checkpoint activity and increase CPU usage. As rule of thumb switching logs at most once every fifteen minutes.
Checkpoint frequency is affected by several factors, including log file size and the setting of the FAST_START_MTTR_TARGET initialization parameter. If the FAST_START_MTTR_TARGET parameter is set to limit the instance recovery time, Oracle automatically tries to checkpoint as frequently as necessary. Under this condition, the size of the log files should be large enough to avoid additional checkpointing due to under sized log files.
The redo logfile sizing advisory is specified by column optimal_logfile_size of v$instance_recovery. This feature require setting the parameter “fast_start_mttr_target” for the advisory to take effect and populate the column optimal_logfile_size.
Also you can obtain redo sizing advice on the Redo Log Groups page of Oracle Enterprise Manager Database Control.
To enable automatic checkpoint tuning, unset FAST_START_MTTR_TARGET or set it to a nonzero value(This is measured in seconds and by default, this feature is not enabled, because FAST_START_MTTR_TARGET has a default value of 0). If you set this parameter to zero this feature will be disabled. When you enable fast-start checkpointing, remove or disable(set to 0) the following initialization parameters:
Enabling fast-start checkpointing can be done statically using the initialization files or dynamically using –
SQL> alter system set FAST_START_MTTR_TARGET=10;