redo log 比较小，切换频率太高。
且经常会checkpoint not completed

加大redolog size:
方法：新增500M的 logfile,drop 以前的logfile

alter database add logfile group 5 ('/oradata/mon/redo05.log') size 500M;
alter database add logfile group 6 ('/oradata/mon/redo06.log') size 500M;
alter database add logfile group 7 ('/oradata/mon/redo07.log') size 500M;
alter database add logfile group 8 ('/oradata/mon/redo08.log') size 500M;

 

SQL> alter database add logfile group 4 ('/oradata/mon/redo04.log') size 500M;
alter database add logfile group 4 ('/oradata/mon/redo04.log') size 500M
*
ERROR at line 1:
ORA-00301: error in adding log file '/oradata/mon/redo04.log' - file cannot be
created
ORA-27038: created file already exists
Additional information: 1

查看文件是否被使用：
[oracle@monstd mon]$ /sbin/fuser redo04.log

mv redo04.log redo04.log.bk

select group#, sequence#,archived,status from v$log;
当redolog已被archived,且状态为inactive，可以删除redo logfile

ALTER DATABASE DROP LOGFILE GROUP 1;
ALTER DATABASE DROP LOGFILE GROUP 2;
ALTER DATABASE DROP LOGFILE GROUP 3;