Sizing Redo Log Files

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. The following query will recommend optimal log file size in megabytes:
SQL> select optimal_logfile_size from v$instance_recovery;

[OR]

Using OEM Database Control: Redo Log File Size Advisor

Redo Log Groups screen --> Actions drop-down list on right, select Sizing Advice and click Go.

NOTE: In Oracle 10g the fast_start_mttr_target parameter should be set to non-zero to enable redo log advisor.