ASM中如何配置多个控制文件（网络转载文章）。[@more@]ASM中如何配置多个控制文件

我们日常对数据库进行配置管理时，为了保证数据库的安全，通常会配置多个控制文件，
以防单一控制文件的损坏引起数据库的宕机。如果数据库采用了ASM存储方案，假如只
创建一个ASM磁盘组的话，控制文件默认只有一个，这样显然无助于数据库的保护。
事实上我们可以通过简单的一些操作把对ASM中的控制文件进行多个配置：

一、将控制文件从文件系统迁移到ASM：

SQL> show parameter control_files

NAME TYPE VALUE

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

control_files string /home/oracle/control01.ctl, /h

ome/oracle/control02.ctl, /hom

e/oracle/control03.ctl

SQL> show parameter db_create_file_dest

NAME TYPE VALUE

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

db_create_file_dest string +DATA

SQL> alter system reset control_files scope=spfile;

alter system reset control_files scope=spfile

*

ERROR at line 1:

ORA-00905: missing keyword

SQL> alter system reset control_files scope=spfile sid='*';

System altered.

SQL> startup nomount

ORACLE instance started.

Total System Global Area 8388608000 bytes

Fixed Size 2086096 bytes

Variable Size 4479519536 bytes

Database Buffers 3892314112 bytes

Redo Buffers 14688256 bytes

dw2:/u01/oracle/product/10g/db/bin>$./rman target /

Recovery Manager: Release 10.2.0.3.0 - Production on Mon Dec 3 10:17:05 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

connected to target database: test (not mounted)

RMAN> restore controlfile from '/home/oracle/control01.ctl';

Starting restore at 2007-12-03 10:17:12

using target database control file instead of recovery catalog

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=1091 devtype=DISK

channel ORA_DISK_1: copied control file copy

output filename=+DATA/test/controlfile/current.1623.640347437

Finished restore at 2007-12-03 10:17:21

二、可以看到ASM默认只会创建一个控制文件+DATA/test/controlfile/current.1623.640347437，
且控制文件的名字由于遵循了ASM的命名方式，比较怪异。我们现在要将名字改为
control01.ctl,control02.ctl,control03.ctl这样比较直观的名字。首先对当前控制文件进行一个备份，
备份的路径为我们想要的ASM上的控制文件：

SQL>startup nomount;
SQL> alter database mount;

Database altered.

SQL> alter database backup controlfile to '+DATA/test/controlfile/control01.ctl';

Database altered.

SQL> alter system set control_files='+DATA/test/controlfile/control01.ctl' scope=spfile;

System altered.

Elapsed: 00:00:00.00

SQL> shutdown immediate

ORA-01507: database not mounted

ORACLE instance shut down.

三、以新的控制文件MOUNT数据库，然后再对控制文件依样进行备份，更改参数文件，成功地配置了多个控制文件：

SQL> startup nomount

ORACLE instance started.

Total System Global Area 8388608000 bytes

Fixed Size 2086096 bytes

Variable Size 4479519536 bytes

Database Buffers 3892314112 bytes

Redo Buffers 14688256 bytes

SQL> alter database mount database;

Database altered.

SQL> alter database backup controlfile to '+DATA/test/controlfile/control02.ctl';

Database altered.

SQL> alter database backup controlfile to '+DATA/test/controlfile/control03.ctl';

Database altered.

SQL> alter system set control_files='+DATA/test/controlfile/control01.ctl',
'+DATA/test/controlfile/control02.ctl','+DATA/test/controlfile/control03.ctl'
scope=spfile;

System altered.

SQL> startup nomount

ORACLE instance started.

Total System Global Area 8388608000 bytes

Fixed Size 2086096 bytes

Variable Size 4479519536 bytes

Database Buffers 3892314112 bytes

Redo Buffers 14688256 bytes

SQL> alter database mount database;

Database altered.

四、通过ASM命令行工具asmcmd可以看到事实上我们设置的控制文件命名规范还是遵照ASM的命名方式的，
它会通过一个LINK链接到我们想要的控制文件名字：

ASMCMD> ls

Backup.2882.640347745

Backup.4733.640348283

Backup.5043.640348291

control01.ctl

control02.ctl

control03.ctl

current.1623.640347437

ASMCMD> rm Backup.2882.640347745

ORA-15032: not all alterations performed

ORA-15028: ASM file '+DATA/TEST/CONTROLFILE/Backup.2882.640347745' not dropped; currently being accessed (DBD ERROR: OCIStmtExecute)

ASMCMD> ls -alt

Type Redund Striped Time Sys Name

CONTROLFILE UNPROT FINE DEC 03 10:00:00 Y none => current.1623.640347437

N control03.ctl => +DATA/TEST/CONTROLFILE/Backup.5043.640348291

N control02.ctl => +DATA/TEST/CONTROLFILE/Backup.4733.640348283

N control01.ctl => +DATA/TEST/CONTROLFILE/Backup.2882.640347745

CONTROLFILE UNPROT FINE DEC 03 10:00:00 Y +DATA/TEST/CONTROLFILE/control03.ctl => Backup.5043.640348291

CONTROLFILE UNPROT FINE DEC 03 10:00:00 Y +DATA/TEST/CONTROLFILE/control02.ctl => Backup.4733.640348283

CONTROLFILE UNPROT FINE DEC 03 10:00:00 Y +DATA/TEST/CONTROLFILE/control01.ctl => Backup.2882.640347745

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