MySQL的主从复制广泛用于数据库备份、故障转移、数据分析等场合。
MySQL主从复制基于主服务器在二进制日志中跟踪所有对数据库的更改（更新、删除等等）。因此，要进行复制，必须在主服务器上启用二进制日志。从服务器从主服务器接收已经记录到其二进制日志的更新，当一个从服务器连接主服务器时，主服务器从日志中读取最后一次成功更新的位置，从服务器接收从那时起发生的更新，并在本机上执行相同的更新，然后等待主服务器通知新的更新。从服务器执行备份不会干扰主服务器，在备份过程中主服务器可以继续处理更新。
测试环境
Master: 192.168.10.201
Slave: 192.168.10.202
端口： 3306
数据库：test2
安装MySQL
yum install mariadb mariadb-server
systemctl enable mariadb
service mariadb start
# Reset root password
mysqladmin -u root password abc@DEF
主服务器配置
主服务器配置文件/etc/my.cnf
[mysqld]
server-id=1
binlog-do-db=test2
relay-log=/var/lib/mysql/mysql-relay-bin
relay-log-index=/var/lib/mysql/mysql-relay-bin.index
log-error=/var/lib/mysql/mysql.err
master-info-file=/var/lib/mysql/mysql-master.info
relay-log-info-file=/var/lib/mysql/mysql-relay-log.info
log-bin=/var/lib/mysql/mysql-bin
重启MySQL
service mariadb restart
赋予REPLICATION SLAVE权限
mysql -uroot -p
GRANT REPLICATION SLAVE ON *.* TO 'slave_user'@'%' IDENTIFIED BY 'password';
FLUSH PRIVILEGES;
FLUSH TABLES WITH READ LOCK;
SHOW MASTER STATUS;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000002 | 469 | test2 | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
注意：记下红色部分，稍后还会用到。
备份数据库
为了备份数据库，需要为数据库中所有表叫上“只读锁” (Read Lock)，再进行dump备份：
mysqldump -u root -p --all-databases --master-data > /root/dbdump.db
备份完成后，可以用以下命令解锁：
mysql -uroot -p
UNLOCK TABLES;
从服务器配置
还原数据库
mysql -u root -p < /root/dbdump.db
从服务器配置文件/etc/my.cnf
[mysqld]
server-id=2
replicate-do-db=test2
relay-log=/var/lib/mysql/mysql-relay-bin
relay-log-index=/var/lib/mysql/mysql-relay-bin.index
log-error=/var/lib/mysql/mysql.err
master-info-file=/var/lib/mysql/mysql-master.info
relay-log-info-file=/var/lib/mysql/mysql-relay-log.info
log-bin=/var/lib/mysql/mysql-bin
重启MySQL
service mariadb restart
连接主服务器
mysql -uroot -p
stop slave;
CHANGE MASTER TO MASTER_HOST='192.168.10.201', MASTER_USER='slave_user', MASTER_PASSWORD='password', MASTER_LOG_FILE='mysql-bin.000002', MASTER_LOG_POS=469;
start slave;
show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.10.201
Master_User: slave_user
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 469
Relay_Log_File: mysql-relay-bin.000004
Relay_Log_Pos: 529
Relay_Master_Log_File: mysql-bin.000002
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB: test2
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 469
Relay_Log_Space: 1107
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
验证
主服务器
mysql -uroot -p
drop test2;
create database test2;
use test2;
create table emp (c int);
insert into emp (c) values (10);
从服务器
在从服务器上，你应该可以看到相同的变化。