单机数据库调整redo log日志大小

1.查看当前日志组成员
SQL> select member from v$logfile; 


MEMBER
--------------------------------------------------------------------------------
/u01/oracle/oradata/orcl/redo03.log
/u01/oracle/oradata/orcl/redo02.log
/u01/oracle/oradata/orcl/redo01.log
2. 查看当前日志组状态：
SQL> select group#,members,bytes/1024/1024,status from v$log; 


    GROUP# MEMBERS BYTES/1024/1024 STATUS
---------- ---------- --------------- ----------------
         1 1 50 ACTIVE
         2 1 50 CURRENT
         3 1 50 INACTIVE
增加日志组


SQL>alter database add logfile group 4 ('/u01/oracle/oradata/orcl/redo04.log') size 100M;
SQL>alter database add logfile group 5 ('/u01/oracle/oradata/orcl/redo05.log') size 100M;
SQL>alter database add logfile group 6 ('/u01/oracle/oradata/orcl/redo06.log') size 100M;
3.切换到新增的日志组上
SQL> alter system switch logfile;
SQL> select group#,members,bytes/1024/1024,status from v$log


    GROUP#    MEMBERS BYTES/1024/1024 STATUS
---------- ---------- --------------- ----------------
         1          1              50 INACTIVE
         2          1              50 INACTIVE
         3          1              50 ACTIVE
         4          1             100 CURRENT
         5          1             100 UNUSED
         6          1             100 UNUSED


 改变检查点
SQL> alter system checkpoint;


System altered.


SQL> select group#,members,bytes/1024/1024,status from v$log


    GROUP#    MEMBERS BYTES/1024/1024 STATUS
---------- ---------- --------------- ----------------
         1          1              50 INACTIVE
         2          1              50 INACTIVE
         3          1              50 INACTIVE
         4          1             100 CURRENT
         5          1             100 UNUSED
         6          1             100 UNUSED
4.删除旧的日志组(1,2,3)
SQL> alter database drop logfile group 1; 


Database altered.


……
多切换几次，验证每组日志是否可以正常使用和切换
SQL> alter system switch logfile;






操作系统下若还有旧的日志文件则在操作系统下删除掉redolog 日志文件
mv  /u01/oracle/oradata/orcl/redo0[1-3].log /tmp