Oracle高可用之dataguard

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:.环境

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;

5.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

6.生成备库的control file

SQL>alter database create standby controlfile as '/oracle/rmanback/ctontrl01.ctl

7.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

mkdir –p $ORACLE_BASE/admin/

cd $ORACLE_BASE/admin/ORACLE_SID

mkdir adump bdump cdump dpdump udump

3.建立密码文件

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 root@192.168.18.2:/oracle/rmanback/

scp /oracle/rmanback/*.ctl root@192.168.18.2:/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

1.在primary database上切换日志

SQL> alter system switch logfile

2.在primary database上运行下面的语句

SQL> select max(sequence#) from v$archived_log;

MAX(SEQUENCE#)

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

17

3.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;