修改redo log大小

总结：

要防止archive log 占满磁盘空间，可以考虑以下办法：

1、 修改redo log的大小

2、 脚本监控 arch目录

u  查看redo log的个数和位置、确认使用的redo log

SQL> select group#, THREAD# ,BYTES,sequence#,archived,status,first_change# from v$log;

SQL> select group#, status, member from v$logfile;‘

结果如下：

SQL>  select group#, THREAD# ,BYTES,sequence#,archived,status,first_change# from v$log;

    GROUP#    THREAD#      BYTES  SEQUENCE# ARC STATUS           FIRST_CHANGE#

---------- ---------- ---------- ---------- --- ---------------- -------------

         1          1  104857600      13546 YES INACTIVE            1.1182E+13

         2          1  104857600      13547 NO  CURRENT             1.1182E+13

         3          1  104857600      13545 YES INACTIVE            1.1182E+13

         4          2  104857600       5341 NO  CURRENT             1.1182E+13

         5          2  104857600       5339 YES INACTIVE            1.1182E+13

         6          2  104857600       5340 YES INACTIVE            1.1182E+13

         7          3  104857600       5320 YES INACTIVE            1.1182E+13

         8          3  104857600       5321 YES INACTIVE            1.1182E+13

         9          3  104857600       5322 NO  CURRENT             1.1182E+13

9 rows selected.

注意：以上表示有三组redo log，每个node三个。每个redo log 100M。

SQL> select group#, status, member from v$logfile;

    GROUP# STATUS  MEMBER

         1         /s16rdata1/s16r/redo01_1.log

         1         /s16rdata2/s16r/redo01_2.log

         2         /s16rdata1/s16r/redo02_1.log

         2         /s16rdata2/s16r/redo02_2.log

         3         /s16rdata1/s16r/redo03_1.log

         3         /s16rdata2/s16r/redo03_2.log

         7         /s16rdata1/s16r/redo07_1.log

         7         /s16rdata2/s16r/redo07_2.log

         8         /s16rdata1/s16r/redo08_1.log

         8         /s16rdata2/s16r/redo08_2.log

         9         /s16rdata1/s16r/redo09_1.log

         9         /s16rdata2/s16r/redo09_2.log

         4         /s16rdata1/s16r/redo04_1.log

         4         /s16rdata2/s16r/redo04_2.log

         5         /s16rdata1/s16r/redo05_1.log

         5         /s16rdata2/s16r/redo05_2.log

         6         /s16rdata1/s16r/redo06_1.log

         6         /s16rdata2/s16r/redo06_2.log

18 rows selected.

u  手动切换日志组、删除group 及 member

1)        alter system switch logfile;

结果：使用的group从group2切换到group 3

2)        aler database drop logfile group 4;

3)        用 rm 删除 redo log files

u  新建redo log，并让其加入到group X中

alter database add logfile group 4 '/THRAC_D00/redo/redo04.a1.log' size 200m;

alter database add logfile group 4 '/THRAC_D00/redo/redo04.a1.log' to group 4;

alter database add logfile group 4 '/THRAC_D00/redo/redo04.b1.log' size 200m;

alter database add logfile group 4 '/THRAC_D00/redo/redo04.b1.log' to group 4;

  （以上命令对不对啊）

Check：

SQL> select group#,sequence#,archived,status,first_change# from v$log;

SQL> select group#, status, member from v$logfile;

以上都可以在线做，但建议避免在高峰期执行，可以在测试机上先测试一下。