配置Mysql server 5.5 的双机备份，也就是master-slave模式。本例子还是一个多database复制的情况。

现在有两个database在同一台mysql server，也就是master，各自有自己的user访问和操作，用于不同的应用程序。这两个database都要通过replication配置，实时复制到另一台mysql server上，也就是slave。

配置步骤：

1. 从master上到处现有的数据
mysqldump -R -E -uroot -p ADB > masteradb.sql;
mysqldump -R -E -uroot -p BDB > masterbdb.sql;

2. 为master和slave定制配置文件/etc/my.cnf，然后启动mysql

vi /etc/my.cnf

###详细内容见附录
service mysql restart

3. 在slave上创建database.
create database ADB;
create database BDB;

4. 在master和slave上配置user和privilege;

GRANT ALL PRIVILEGES ON ADB.* TO usera@`%` IDENTIFIED BY 'pass' WITH GRANT OPTION;
GRANT ALL PRIVILEGES ON ADB.* TO usera@`localhost` IDENTIFIED BY 'pass' WITH GRANT OPTION;
GRANT ALL PRIVILEGES ON BDB.* TO userb@`%` IDENTIFIED BY 'pass' WITH GRANT OPTION;
GRANT ALL PRIVILEGES ON BDB.* TO userb@`localhost` IDENTIFIED BY 'pass' WITH GRANT OPTION;
flush privileges;

5. 在master上配置用于数据复制的user和privilege;

grant SUPER ON *.* TO 'auser'@'%' IDENTIFIED BY 'pass' WITH GRANT OPTION;
grant SUPER ON *.* TO 'buser'@'%' IDENTIFIED BY 'pass' WITH GRANT OPTION;
GRANT SELECT ON mysql.proc TO 'auser'@'%' IDENTIFIED BY 'pass' WITH GRANT OPTION;
GRANT SELECT ON mysql.proc TO 'buser'@'%' IDENTIFIED BY 'pass' WITH GRANT OPTION;
GRANT REPLICATION SLAVE ON *.* TO repluser IDENTIFIED BY 'pass';
flush privileges;

6. 在master上运行下列命令，得到master的状态，包含binlog的文件名和当前位置
mysql> show master status;
+------------------+----------+--------------------------------+------------------+
| File             | Position | Binlog_Do_DB                   | Binlog_Ignore_DB |
+------------------+----------+--------------------------------+------------------+
| mysql-bin.000001 |   000173| ADB,BDB |                  |
+------------------+----------+--------------------------------+------------------+
1 row in set (0.02 sec)

7. 在slave配置复制来源，包括hostname，user，password，binlog文件名，位置。
CHANGE MASTER TO MASTER_HOST='10.224.106.225', MASTER_USER='repluser', MASTER_PASSWORD='pass', master_log_file='mysql-bin.000001', master_log_pos=173;
start slave;

8. 运行下列命令查看slave的当前状态。

show slave status\G

结果出现

             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes

表示数据同步复制已经成功运行。

提示：如果show slave status\G 出现了错误，运行下列命令跳过，在重启slave
SET GLOBAL SQL_SLAVE_SKIP_COUNTER =100;start slave;
show slave status\G;
stop slave;
SET GLOBAL SQL_SLAVE_SKIP_COUNTER =0;start slave;

附录：

master my.cnf配置

[client]
port            = 3306
socket          = /var/lib/mysql/mysql.sock


[mysqld]
port            = 3306
socket          = /var/lib/mysql/mysql.sock
skip-external-locking
key_buffer = 384M
max_allowed_packet = 32M
table_open_cache = 5120
key_buffer_size = 64M
sort_buf