MySQL传统主从配置
mysql主从
主从简介
在现代企业中，数据显得尤为重要，而存储数据的数据库选择又五花八门，但无论是何种数据库，均存在着一种隐患。
想几个问题：
用一台数据库存放数据，若此数据库服务器宕机了导致数据丢失怎么办？
业务量大了，数据多了，访问的人多了，一台数据库无法保证服务质量了怎么办？
主从作用
实时灾备，用于故障切换
读写分离，提供查询服务
备份，避免影响业务
主从形式
一主一从
主主复制
一主多从—扩展系统读取的性能，因为读是在从库读取的
多主一从—5.7开始支持
联级复制
主从复制原理
主从复制步骤：
主库将所有的写操作记录到binlog日志中并生成一个log dump线程，将binlog日志传给从库的I/O线程
从库生成两个线程，一个I/O线程，一个SQL线程
I/O线程去请求主库的binlog，并将得到的binlog日志写到relay log（中继日志） 文件中
SQL线程，会读取relay log文件中的日志，并解析成具体操作，来实现主从的操作一致，达到最终数据一致的目的
主从复制配置
主从复制配置步骤：
确保从数据库与主数据库里的数据一样
在主数据库里创建一个同步账号授权给从数据库使用
配置主数据库（修改配置文件）
配置从数据库（修改配置文件）
需求：
搭建两台MySQL服务器，一台作为主服务器，两台台作为从服务器，主服务器进行写操作，从服务器进行读操作
环境说明：
| 数据库角色 | IP | 应用与系统版本 | 有无数据 |
|---|---|---|---|
| 主数据库 | 192.168.170.128 | centos8/redhat8 mysql-5.7 | 无数据 |
| 从数据库 | 192.168.170.129 | centos8/redhat8 mysql-5.7 | 无数据 |
| 从数据库 | 192.168.170.130 | centos8/redhat8 mysql-5.7 | 无数据 |
mysql安装
分别在主从三台服务器上安装mysql-5.7版本，此处略过安装步骤，若有疑问请参考二进制格式安装MySQL
mysql主从配置
先把三台服务器的防火墙关闭
#主
[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; v>
Active: inactive (dead)
Docs: man:firewalld(1)
July 03 23:50:55 localhost.localdomain systemd[1]: Starting firewalld - dy>
July 03 23:50:56 localhost.localdomain systemd[1]: Started firewalld - dyn>
July 03 23:50:57 localhost.localdomain firewalld[932]: WARNING: AllowZoneD>
July 03 23:50:02 localhost.localdomain systemd[1]: Stopping firewalld - dy>
July 03 23:50:03 localhost.localdomain systemd[1]: firewalld.service: Succ>
July 03 23:50:03 localhost.localdomain systemd[1]: Stopped firewalld - dyn>
[root@localhost ~]# systemctl disable firewalld
[root@localhost ~]# getenforce
Enforcing
[root@localhost ~]# setenforce 0
[root@localhost ~]# getenforce
Permissive
#从1
[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# systemctl stastus firewalld
Unknown operation stastus.
[root@localhost ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; ve>
Active: inactive (dead) since Tue 2022-07-03 23:51:38 CST; 21s ago
Docs: man:firewalld(1)
Process: 916 ExecStart=/usr/sbin/firewalld --nofork --nopid $FIREWALLD_>
Main PID: 916 (code=exited, status=0/SUCCESS)
July 03 23:52:06 localhost.localdomain systemd[1]: Starting firewalld - dy>
July 03 23:52:07 localhost.localdomain systemd[1]: Started firewalld - dyn>
July 03 23:52:08 localhost.localdomain firewalld[916]: WARNING: AllowZoneD>
July 03 23:52:38 localhost.localdomain systemd[1]: Stopping firewalld - dy>
July 03 23:52:38 localhost.localdomain systemd[1]: firewalld.service: Succ>
July 03 23:52:38 localhost.localdomain systemd[1]: Stopped firewalld - dyn>
[root@localhost ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@localhost ~]# getenforce
Enforcing
[root@localhost ~]# setenforce 0
[root@localhost ~]# setenforce 0
[root@localhost ~]# getenforce
Permissive
#从2
[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; ve>
Active: inactive (dead) since Tue 2022-07-03 23:53:21 CST; 6s ago
Docs: man:firewalld(1)
Process: 932 ExecStart=/usr/sbin/firewalld --nofork --nopid $FIREWALLD_>
Main PID: 932 (code=exited, status=0/SUCCESS)
July 04 23:53:44 localhost.localdomain systemd[1]: Starting firewalld - dy>
July 04 23:53:44 localhost.localdomain systemd[1]: Started firewalld - dyn>
July 04 23:53:45 localhost.localdomain firewalld[932]: WARNING: AllowZoneD>
July 04 23:53:21 localhost.localdomain systemd[1]: Stopping firewalld - dy>
July 04 23:53:21 localhost.localdomain systemd[1]: firewalld.service: Succ>
July 04 23:53:21 localhost.localdomain systemd[1]: Stopped firewalld - dyn>
[root@localhost ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@localhost ~]# getenforce
Enforcing
[root@localhost ~]# setenforce 0
[root@localhost ~]# getenforce
Permissive
查看各个服务器中的mysq中数据是否一致
# 主
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
# 从1
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.01 sec)
# 从2
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.01 sec)
在主数据库里创建一个同步账号授权给从数据库使用
mysql> CREATE USER 'lzx'@'192.168.170.129' IDENTIFIED BY '1';
Query OK, 0 rows affected (0.00 sec)
mysql> GRANT REPLICATION SLAVE ON *.* TO 'lzx'@'192.168.170.129';
Query OK, 0 rows affected (0.00 sec)
mysql> CREATE USER 'lzx'@'192.168.170.130' IDENTIFIED BY '1';
Query OK, 0 rows affected (0.00 sec)
mysql> GRANT REPLICATION SLAVE ON *.* TO 'lzx'@'192.168.170.130';
Query OK, 0 rows affected (0.00 sec)
配置主数据库
[root@localhost ~]# vim /etc/my.cnf
//添加以下内容
[mysqld3306]
datadir = /opt/data/3306
port = 3306
socket = /tmp/mysql3306.sock
pid-file = /opt/data/3306/mysql_3306.pid
log-error=/var/log/3306.log
log-bin=mysqld-bin //启用binlog日志
server-id=10 //数据库服务器唯一标识符，主库的server-id值必须比从库的小
//重启MySQL服务
[root@localhost ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL.. SUCCESS!
//查看主库的状态
mysql> show master status;
+-------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| mysqld-bin.000001 | 154 | | | |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
配置从数据库
从1
[root@localhost ~]# vim /etc/my.cnf
//添加以下内容
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve
server-id=20 //设置从库的唯一标识符，从库的server-id值必须大于主库的该值
relay-log=mysql-relay-bin //启用中继日志relay-log
//重启从库的MySQL服务
[root@localhost ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL. SUCCESS!
//配置并启动主从复制
ysql> CHANGE MASTER TO
-> MASTER_HOST='192.168.170.128',
-> MASTER_USER='lzx',
-> MASTER_PASSWORD='1',
-> MASTER_LOG_FILE='mysqld-bin.000001',
-> MASTER_LOG_POS=154;
Query OK, 0 rows affected, 2 warnings (0.01 sec)
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
//查看从服务器状态
mysql> show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.170.128
Master_User: lzx
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysqld-bin.000001
Read_Master_Log_Pos: 154
Relay_Log_File: mysql-relay-bin.000002
Relay_Log_Pos: 321
Relay_Master_Log_File: mysqld-bin.000001
Slave_IO_Running: Yes //此次必须为yes
Slave_SQL_Running: Yes //此次必须为yes
Replicate_Do_DB:
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: 154
Relay_Log_Space: 528
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: 10
Master_UUID: 6b52bbf9-b198-11eb-9706-000c29a69e07
Master_Info_File: /opt/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)
从2
[root@localhost ~]# vim /etc/my.cnf
//添加以下内容
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve
server-id=20 //设置从库的唯一标识符，从库的server-id值必须大于主库的该值
relay-log=mysql-relay-bin //启用中继日志relay-log
//重启从库的MySQL服务
[root@localhost ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL. SUCCESS!
//配置并启动主从复制
ysql> CHANGE MASTER TO
-> MASTER_HOST='192.168.170.128',
-> MASTER_USER='lzx',
-> MASTER_PASSWORD='1',
-> MASTER_LOG_FILE='mysqld-bin.000001',
-> MASTER_LOG_POS=154;
Query OK, 0 rows affected, 2 warnings (0.01 sec)
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
//查看从服务器状态
mysql> show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.170.128
Master_User: lzx
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysqld-bin.000001
Read_Master_Log_Pos: 154
Relay_Log_File: mysql-relay-bin.000002
Relay_Log_Pos: 321
Relay_Master_Log_File: mysqld-bin.000001
Slave_IO_Running: Yes //此次必须为yes
Slave_SQL_Running: Yes //此次必须为yes
Replicate_Do_DB:
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: 154
Relay_Log_Space: 528
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: 10
Master_UUID: 6b52bbf9-b198-11eb-9706-000c29a69e07
Master_Info_File: /opt/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)
测试验证
在主服务器的数据库中创建bwxh库，在lzx库中创建表student并插入数据：
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
mysql> create database zz;
Query OK, 1 row affected (0.00 sec)
mysql> use zz;
Database changed
mysql> insert student(name,age) values('tom',18),('jerry',23),('zhangshan',
,20);
Query OK, 3 rows affected (0.07 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> select * from student;
+----+-----------+------+
| id | name | age |
+----+-----------+------+
| 1 | tom | 18 |
| 2 | jerry | 23 |
| 3 | zhangshan | 20 |
+----+-----------+------+
3 rows in set (0.00 sec)
在从数据库中查看数据是否同步：
//从1
mysql> select * from zz.student;
+----+-----------+------+
| id | name | age |
+----+-----------+------+
| 1 | tom | 18 |
| 2 | jerry | 23 |
| 3 | zhangshan | 20 |
+----+-----------+------+
3 rows in set (0.01 sec)
//从2
mysql> select * from zz.student;
+----+-----------+------+
| id | name | age |
+----+-----------+------+
| 1 | tom | 18 |
| 2 | jerry | 23 |
| 3 | zhangshan | 20 |
+----+-----------+------+
3 rows in set (0.00 sec)
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