oracle 의 online log file size 조절하는 법

SQL> alter database add logfile '/home/shawn/work/mdw/integrator/test/ora1/dbs/slog1.dbf' size 4m;
SQL> alter database drop logfile '/home/shawn/work/mdw/integrator/test/ora1/dbs/log1.dbf'
SQL> select * from v$logfile;