oracle dataguard

Oracle DataGuard数据备份方案详解

本文介绍如何使用RMAN备份创建备库(dataguard)。Oracle DataGuard是一种数据库级别的HA方案，最主要功能是冗灾、数据保护、故障恢复等。
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Oracle DataGuard是一种数据库级别的HA方案，最主要功能是冗灾、数据保护、故障恢复等。

在生产数据库的"事务一致性"时，使用生产库的物理全备份(或物理COPY)创建备库，备库会通过生产库传输过来的归档日志(或重做条目)自动维护备用数据库。将重做数据应用到备用库。本文介绍使用RMAN备份创建备库(dataguard).

一:Oracle DataGuard环境概述

1.软件环境

操作系统Red Linux Enterprise as 5

数据库版本Oracle 10g release 2

2.primary databae

IP:192.168.18.1

ORACLE_SID=db1

db_unique_name=db1

3.standby database

IP:192.168.18.2

ORACLE_SID=standby

db_unique_name=standby

二,主数据库(db1)做准备

1.设置主数据库为Force logging

SQL> alter database force logging;  
2.创建密码文件

cd $ORACLE_HOME/dbs/  
orapwdfile=orapwdb1 password=123456 force=y  
3.修改主库的初始化参数

alter system set log_archive_config='dg_config=(db1,standby)' scope=both;  
alter system set log_archive_dest_1='location=/u01/db1/arch' scope=both;  
alter system set db_unique_name='db1' scope=both;  
4.生成数据库备份

RMAN> connect target sys/123456  
RMAN> backup database format='/oracle/rmanback/%d_%s.dbf' plus archivelog;  
[oracle@oracle rmanback]$ ls  
DB1_1.dbfDB1_2.dbf  
5.生成备库的control file

SQL>alter database create standby controlfile as '/oracle/rmanback/ctontrl01.ctl  
6.配置listener.ora 和tnsnames.ora文件

启动lintener.ora,

[oracle@oracle dbs]$ lsnrctl status  
LSNRCTL for Linux: Version 10.2.0.4.0 - Production on 14-JUN-2009 02:54:29  
Service "db1" has 1 instance(s).  
Instance "db1", status READY, has 1 handler(s) for this service...  
Service "db1_XPT" has 1 instance(s).  
Instance "db1", status READY, has 1 handler(s) for this service...  
The command completed successfully  
配置rnsnames.ora

vi $ORACLE_HOME/network/admin/tnsnames.ora  
db1 =  
  (DESCRIPTION =  
    (ADDRESS_LIST =  
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.18.1)(PORT = 1521))  
    )  
    (CONNECT_DATA =  
      (SERVICE_NAME = db1)  
standby =  
  (DESCRIPTION =  
    (ADDRESS_LIST =  
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.18.2)(PORT = 1521))  
    )  
    (CONNECT_DATA =  
      (SERVICE_NAME = standby)  
    )  
  ) 
三.创建standby database

1.设置环境变量并安装oracle软件

#环境变量设成与主库一样  
#只安装软件不安装库  
./runInstaller –silent –responseFile /tmp/installoracle.rsp  
2.建立相关的目录

cd $ORACLE_HOME/dbs/  
orapwdfile=orapwSID password=123456 force=y  
#注要密码要与主库的一样, 否则会归档失败  
3.建立密码文件

cd $ORACLE_HOME/dbs/  
orapwd  file=orapwSID password=123456 force=y  
#注要密码要与主库的一样, 否则会归档失败 
3.建立参数文件(pfile)

db_name = standby   
shared_pool_size = 120M  
undo_management = AUTO  
undo_tablespace = undotbs  
sga_max_size = 200M  
sga_target = 160M  
db_2k_cache_size = 4M  
   
standby_file_management=AUTO  
fal_server='db1' 
fal_client='standby' 
log_archive_dest_1='location=/u01/app/oracle/product/10.2.0/dbs/arch' 
log_archive_dest_2='SERVICE=db1 REOPEN=300' 
log_archive_dest_state_1='ENABLE' 
log_archive_dest_state_2='ENABLE'  
4.CP主数据库RMAN备份及控制文件到备库

注意:备份存放位置要与primary database RMAN备份文件的位置相同. 控制文件存放位置要与生成standby database controlfile的位置相同

scp /oracle/rmanback/*.dbf [email protected]:/oracle/rmanback/  
scp /oracle/rmanback/*.ctl [email protected]:/oracle/oracle/oradata/standby/  
5.利用备用的控制文件,把备用数据库启到mount

SQL>connect / as sysdba  
connnpcted to an idle instance．  
SQL>startup nomount pfile=$ORACLE_HOME/dbs/initstandby.ora  
SQL>alter database mount standby database 
6. 配置listener.ora 和tnsnames.ora文件.

与主库相同启动listener,tnsnames.ora也与主库配置的一样,

当主备库的监听都启动后,进行测试,以例下面能顺利进行

tnsping db1  
tnsping standby  
SQL> sqlplus sys/123456@db1  
SQL> sqlplus sys/123456@standby  
7.转储数据库

RMAN>connect target /  
connected to target database：TEST(DBID=788075692)  
RMAN> restore database  
8.恢复数据库。

SQL>recover managed standby database disconnect from session；  
#如果有需要应用的日志并想手工应用，可以运行如下命令  
SQL>recover automatic standby database；  
9.检查standby database是否创建成功

a.在primary database 上切换日志

SQL> alter system switch logfile  
b.在primary database上运行下面的语句

SQL> select max(sequence#) from v$archived_log;  
MAX(SEQUENCE#)  
--------------  
17  
c. 在standby database上运行下面的语句

SQL> select sequence# ,applied from v$archived_log order by sequence#;  
 SEQUENCE# APP  
--------------------- ---  
15YES  
16YES  
17YES  
若在上步中的max sequence#在的的app状态为YES说明standby database 成功创建.

10. 以spfile启动并设为只读

SQL> create spfile from pfile;  
SQL> shutdown immedaite  
SQL> startup mount  
SQL> alter database recover managed standby database disconnect from session;  
SQL> alter database open read only;