修改online redo日志文件大小

要将日志文件组1，2，3从100M修改到200M方法如下
$ ls
control01.ctl  drsys01.dbf    redo01.log     temp01.dbf     xdb01.dbf
control02.ctl  example01.dbf  redo02.log     tools01.dbf
control03.ctl  indx01.dbf     redo03.log     undotbs01.dbf
cwmlite01.dbf  odm01.dbf      system01.dbf   users01.dbf
$ ls -l redo01.log
-rw-r-----   1 oracle   dba       104858112 Jan 04 16:34 redo01.log
$ du -m redo01.log
100.00  redo01.log

登陆SQLPLUS
--------------------
$ sqlplus /nolog

SQL*Plus: Release 9.2.0.7.0 - Production on Fri Jan 4 16:48:40 2008

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.

SQL> conn / as sysdba;
Connected to an idle instance.
SQL> startup
ORACLE instance started.

Total System Global Area 1377274120 bytes
Fixed Size                   743688 bytes
Variable Size             738197504 bytes
Database Buffers          637534208 bytes
Redo Buffers                 798720 bytes
Database mounted.
Database opened.
SQL> select group# from v$log;

    GROUP#
----------
         1
         2
         3

创建日志文件组4,5
---------------------------
SQL> alter database add logfile group 4 '/opt/oracle/product/9i/oradata/oracle9i/redo04.log' size 200M;

Database altered.

SQL> alter database add logfile group 5 '/opt/oracle/product/9i/oradata/oracle9i/redo05.log' size 200M;

Database altered.

将日志文件组切换到新建立的4,5日志文件组上
--------------------------------------------------------------
SQL> alter system switch logfile;

System altered.

SQL> alter system switch logfile;

System altered.

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

    GROUP# STATUS
---------- ----------------
         1 INACTIVE
         2 INACTIVE
         3 INACTIVE
         4 INACTIVE
         5 CURRENT

删除已有的1,2,3日志文件组
---------------------------------------
SQL> alter database drop logfile group 1;

Database altered.

SQL> alter database drop logfile group 2;

Database altered.

SQL> alter database drop logfile group 3;

Database altered.

增加新的日志文件1,2,3，并设定容量为200M
------------------------------------------------------------
SQL> alter database add logfile group 1 '/opt/oracle/product/9i/oradata/oracle9i/redo01.log' size 200M;

Database altered.

SQL> alter database add logfile group 2 '/opt/oracle/product/9i/oradata/oracle9i/redo02.log' size 200M;

Database altered.

SQL> alter database add logfile group 3 '/opt/oracle/product/9i/oradata/oracle9i/redo03.log' size 200M;

Database altered.

SQL> alter system switch logfile;

System altered.

SQL> alter system switch logfile;

System altered.

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

    GROUP# STATUS
---------- ----------------
         1 INACTIVE
         2 CURRENT
         3 UNUSED
         4 INACTIVE
         5 INACTIVE

删除刚刚增加的日志文件组4,5
-----------------------------------------
SQL> alter database drop logfile group 4;

Database altered.

SQL> alter database drop logfile group 5;

Database altered.

注意：每一步删除drop操作，都需要手工删除os中的实体文件。
           另外注意备份控制文件。

 

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