一、主备模式
也叫冷备模式，通俗点讲，就是两台服务器都安装了MySQL，一台当作主服务器，一台当作备服务器，备服务器会把主服务器的MySQL数据同步过来，当主服务器故障或者挂掉的时候可以让备服务器顶上，也保证数据不会丢失
二、注意事项
如果是虚拟机直接拷贝的服务器，要注意修改MySQL的uuid值，两台是不可以一样的
vi /usr/local/mysql/data/auto.cnf
# 随便修改其中一个数字或字母就行
# 修改保存后记得重启MySQL
另外一个还需要注意的就是防火墙，要把MySQL的端口添加到防火墙里面，我这边直接关闭了
# 查看防火墙状态，开启的话会有 active (running) 字样
systemctl status firewalld.service
# 关闭放获取，关闭的话会有 inactive (dead) 字样
systemctl stop firewalld.service
三、开始搭建
1、环境
系统：CentOS 7.0
MySQL：5.7.29
主服务器IP：192.168.74.132
备服务器IP：192.168.74.140
2、创建库 test
两台服务器分别创建数据库test和一张表
# 创建库
create database test;
# 创建表
use test;
create table tb_mobile( mobile VARCHAR(20) comment'手机号码', time timestamp DEFAULT now() comment'时间' );
3、在主机创建同步用户
# 创建用户
grant replication slave on *.* to 'demo'@'192.168.74.140' identified by '1qaz2wsx';
# 立即生效
flush privileges;
4、在备机上用刚创建的demo用户远程登录
# 在备机上远程登录主机的MySQL
mysql -h192.168.74.132 -udemo -p
5、修改主机的my.cnf文件
# ps：以前版本是没有 !includedir /etc/my.cnf.d 这一行的
[client]
default-character-set=utf8
socket=/usr/local/mysql/data/mysql.sock
[mysqld]
# 唯一ID
server-id = 1
log-bin=mysql-bin
# 记录日志的数据库
binlog-do-db = test
# 不记录日志的数据库
binlog-ignore-db = mysql
port=3306
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
socket=/usr/local/mysql/data/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd
[mysqld_safe]
log-error=/usr/local/mysql/mysql-log/error.log
pid-file=/usr/local/mysql/data/mysql.pid
#
# include all files from the config directory
#
!includedir /etc/my.cnf.d
6、重启MySQL
7、在主机上锁定数据库表
flush tables with read lock;
8、查看主机状态
show master status\G;
# 结果如下，记录一下 File 参数 和 Position 参数
mysql> show master status\G;
*************************** 1. row ***************************
File: mysql-bin.000001
Position: 154
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
Executed_Gtid_Set:
1 row in set (0.00 sec)
9、修改备服务器的my.cnf文件
[client]
default-character-set=utf8
socket=/usr/local/mysql/data/mysql.sock
[mysqld]
# 不能和主机一样
server-id = 2
log-bin=mysql-bin
replicate-do-db = test
replicate-ignore-db = mysql,information_schema,performance_schema
port=3306
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
socket=/usr/local/mysql/data/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd
[mysqld_safe]
log-error=/usr/local/mysql/mysql-log/error.log
pid-file=/usr/local/mysql/data/mysql.pid
#
# include all files from the config directory
#
!includedir /etc/my.cnf.d
10、重启备机MySQL服务
11、在备机进入MySQL执行 change master命令
# 先关闭 slave
stop slave;
# 设置连接
change master to master_host='192.168.74.132',master_user='demo',master_password='1qaz2wsx',master_log_file='mysql-bin.000001',master_log_pos=154;
# 再开启 slave
start slave;
# 如果遇到报错，先关闭
stop slave
# 重置 slave
reset slave
# 再重复前面 关闭-设置连接-开启 的步骤
12、查看slave 的状态
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.74.132
Master_User: demo
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 154
Relay_Log_File: localhost-relay-bin.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000001
# 主要是这两个 yes 代表通了
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB: test
Replicate_Ignore_DB: mysql,information_schema,performance_schema
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: 154
Relay_Log_Space: 531
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
Master_UUID: be8b52d3-7f04-11ea-a454-000c29e3bb87
Master_Info_File: /usr/local/mysql/data/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)
四、开始同步测试
1、先在主机执行解锁
unlock tables;
2、在主机添加数据
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql>
mysql>
mysql>
mysql> insert into tb_mobile values('1111',now());
Query OK, 1 row affected (0.01 sec)
mysql> select * from tb_mobile;
+--------+---------------------+
| mobile | time |
+--------+---------------------+
| 1111 | 2020-04-16 22:06:46 |
+--------+---------------------+
1 row in set (0.00 sec)
3、在备机上查看同步数据
mysql> use test;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from tb_mobile;
+--------+---------------------+
| mobile | time |
+--------+---------------------+
| 1111 | 2020-04-16 22:06:46 |
+--------+---------------------+
1 row in set (0.00 sec)
4、同步成功。结束