Oracle数据库灾难恢复教程构建强大的DG双活防护体系（oracle dg教程）

Oracle数据库灾难恢复教程：构建强大的DG双活防护体系

在企业的生产环境中，一旦遭遇数据丢失或系统崩溃等灾难，就可能影响到企业的正常运营。为了解决这个问题，Oracle提供了一个双活(DG)方案，能够实现数据库的热备份和灾难恢复。本文将详细介绍如何构建一个高可靠的双活防护体系。

实验环境说明

本实验环境基于Oracle 12c数据库和linux系统进行搭建。主服务器为主节点，副服务器为备节点，两台服务器间通过公共网段进行通信。

配置主节点

1. 创建数据文件和日志文件

在主节点上，创建数据文件和日志文件，并设置文件大小和块数，具体操作如下：

SQL> create tablespace dg_data datafile '/u01/app/oracle/oradata/orcl/dg_data.dbf' size 100M blocksize 8K;
SQL> create tablespace dg_indx datafile '/u01/app/oracle/oradata/orcl/dg_indx.dbf' size 50M blocksize 8K;
SQL> alter database add logfile group 1 ('/u01/app/oracle/oradata/orcl/redo01.log') size 50M;
SQL> alter database add logfile group 2 ('/u01/app/oracle/oradata/orcl/redo02.log') size 50M;
SQL> alter database add logfile group 3 ('/u01/app/oracle/oradata/orcl/redo03.log') size 50M;

2. 开启归档模式

在主节点上开启归档模式，并设置归档目录，具体操作如下：

SQL> shutdown immediate;
SQL> startup mount;
SQL> alter database archivelog;
SQL> alter database open;
SQL> archive log list;
SQL> alter system set log_archive_dest_1='location=/u01/app/oracle/archivelog' scope=both;

3. 创建同步复制组

在主节点上创建一个同步复制组，具体操作如下：

SQL> alter system set dg_broker_start=true;
SQL> alter system set dg_broker_config_file1='/u01/app/oracle/product/12.1.0/dbhome_1/dbs/dr1_orcl.dat' scope=both;
SQL> alter system set dg_broker_config_file2='/u01/app/oracle/product/12.1.0/dbhome_1/dbs/dr2_orcl.dat' scope=both;
SQL> alter system set log_archive_dest_2='service=dr1' scope=both;
SQL> alter system set log_archive_dest_3='service=dr2' scope=both;
SQL> alter system set dg_broker_config_file1='/u01/app/oracle/product/12.1.0/dbhome_1/dbs/dr1_orcl.dat' scope=both;
SQL> alter system set dg_broker_config_file2='/u01/app/oracle/product/12.1.0/dbhome_1/dbs/dr2_orcl.dat' scope=both;
SQL> alter system set service_names='orcl,dr1,dr2' scope=spfile;
SQL> create database link dr1 connect to system identified by Password using 'dr1';
SQL> create database link dr2 connect to system identified by Password using 'dr2';
SQL> alter system switch logfile;

如上所示，创建了两个同步复制组，分别为dr1和dr2。并且配置了归档目录，以及创建了dr1和dr2的数据库链接。

配置备节点

1. 在备节点上创建数据文件和日志文件

在备节点上创建数据文件和日志文件，并设置文件大小和块数，具体操作如下：

SQL> create tablespace dg_data datafile '/u01/app/oracle/oradata/orcl/dg_data.dbf' size 100M blocksize 8K;
SQL> create tablespace dg_indx datafile '/u01/app/oracle/oradata/orcl/dg_indx.dbf' size 50M blocksize 8K;
SQL> alter database add logfile group 1 ('/u01/app/oracle/oradata/orcl/redo01.log') size 50M;
SQL> alter database add logfile group 2 ('/u01/app/oracle/oradata/orcl/redo02.log') size 50M;
SQL> alter database add logfile group 3 ('/u01/app/oracle/oradata/orcl/redo03.log') size 50M;

2. 还原主节点备份到备节点

在备节点上还原主节点的备份，并创建数据字典。这里假设主节点的备份已经存储在了/u01/app/oracle/backup目录下。

$ cp /u01/app/oracle/backup/backup.xxx /tmp
$ cd /tmp
$ tar -xf backup.xxx
$ su - oracle
$ export ORACLE_SID=orcl
$ rman target sys/Password@orcl auxiliary sys/Password@orcl
RMAN> run {
allocate channel ch1 type disk;
restore controlfile from '/tmp/controlfile.xxx';
alter database mount standby database;
recover standby database;
}

3. 开启归档模式

在备节点上开启归档模式，并设置归档目录，具体操作如下：

SQL> shutdown immediate;
SQL> startup mount;
SQL> alter database archivelog;
SQL> alter database open;
SQL> archive log list;
SQL> alter system set log_archive_dest_1='location=/u01/app/oracle/archivelog' scope=both;

配置主备节点

1. 在主备节点上创建tnsnames.ora文件

在主备节点上创建tnsnames.ora文件，配置主备节点之间的监听，具体操作如下：

$ cd $ORACLE_HOME/network/admin
$ vi tnsnames.ora

ORCL =
 (DESCRIPTION =
  (ADDRESS = (PROTOCOL = TCP)(HOST = 主服务器IP)(PORT = 1521))
  (CONNECT_DATA =
   (SERVER = DEDICATED)
   (SERVICE_NAME = orcl)
  )
 )
DR1 =
 (DESCRIPTION =
  (ADDRESS = (PROTOCOL = TCP)(HOST = 备服务器IP)(PORT = 1521))
  (CONNECT_DATA =
   (SERVER = DEDICATED)
   (SERVICE_NAME = dr1)
  )
 )
DR2 =
 (DESCRIPTION =
  (ADDRESS = (PROTOCOL = TCP)(HOST = 备服务器IP)(PORT = 1521))
  (CONNECT_DATA =
   (SERVER = DEDICATED)
   (SERVICE_NAME = dr2)
  )
 )

2. 在主备节点的listener.ora文件中配置监听服务

在主服务器和备服务器上的listener.ora文件中分别添加以下内容：

主服务器listener.ora文件配置

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (GLOBAL_DBNAME = orcl)
      (SID_NAME = orcl)
      (ORACLE_HOME = /u01/app/oracle/product/12.1.0/dbhome_1)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = dr1_dgmgrl)
      (SID_NAME = dr1)
      (ORACLE_HOME = /u01/app/oracle/product/12.1.0/dbhome_1)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = dr2_dgmgrl)
      (SID_NAME = dr2)
      (ORACLE_HOME = /u01/app/oracle/product/12.1.0/dbhome_1)
    )
  )

ADR_BASE_LISTENER = /u01/app/oracle

备服务器listener.ora文件配置

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (GLOBAL_DBNAME = orcl)
      (SID_NAME = orcl)
      (ORACLE_HOME = /u01/app/oracle/product/12.1.0/dbhome_1)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = dr1_dgmgrl)
      (SID_NAME = dr1)
      (ORACLE_HOME = /u01/app/oracle/product/12.1.0/dbhome_1)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = dr2_dgmgrl)
      (SID_NAME = dr2)
      (ORACLE_HOME = /u01/app/oracle/product/12.1.0/dbhome_1)
    )
  )

ADR_BASE_LISTENER = /u01/app/oracle

3. 配置DG Broker

在主节点上配置DG Broker：

[oracle@localhost ~]$ dgmgrl /
DGMGRL> connect sys/Password@orcl
DGMGRL> create configuration 'orcl_dgmgrl' as primary database is 'orcl' connect identifier is 'orcl';
DGMGRL>