MySQL的主从同步
MySQL的主从同步
1.MySQL中从同步原理
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简介
MySQL主从同步是一种数据库复制技术，它可以将一台MySQL数据库（称为主服务器）的数据复制到另一台或多台MySQL数据库（称为从服务器）。主从同步可以用于以下目的：
- 主服务器将所有数据变更记录到二进制日志（binlog）中。
- 从服务器连接到主服务器，并从主服务器的二进制日志中获取数据变更信息。
- 从服务器将获取到的数据变更信息应用到自己的数据库中，从而使主服务器和从服务器的数据保持一致。
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基本原理、
- 主服务器将所有数据变更记录到二进制日志（binlog）中。
- 从服务器连接到主服务器，并从主服务器的二进制日志中获取数据变更信息。
- 从服务器将获取到的数据变更信息应用到自己的数据库中，从而使主服务器和从服务器的数据保持一致。
2.基于binlog主从同步
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在三个虚拟机下分别安装mysql
# 在三个虚拟机下分别安装mysql root@openEulter-1 ~]# dnf install mysql-server -y -
主库配置
[root@openEulter-1 ~]# vim /etc/my.cnf [mysqld] server_id=1 # 启动服务 [root@openEulter-1 ~]# systemctl enable --now mysqld # 创建用户并授权 mysql> create user rep@'172.25.%.%' identified by '123456'; mysql> grant replication slave on *.* to rep@'172.25.%.%'; mysql> show master status; +---------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +---------------+----------+--------------+------------------+-------------------+ | binlog.000003 | 707 | | | | +---------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec) -
从库1配置
[root@openEulter-1 ~]# vim /etc/my.cnf [mysqld] server_id=2 # 重启服务 [root@openEulter-1 ~]# systemctl restart mysqld [root@openEulter-1 ~]# mysql mysql> change master to -> master_host='172.25.254.100', -> master_user='rep', -> master_password='123456', -> master_log_file='binlog.000003', -> master_log_pos=707, -> get_master_public_key=1; # 检验 mysql> start slave; mysql> show slave status \G *************************** 1. row *************************** Slave_IO_State: Waiting for source to send event Master_Host: 172.25.254.100 Master_User: rep Master_Port: 3306 Connect_Retry: 60 Master_Log_File: binlog.000003 Read_Master_Log_Pos: 707 Relay_Log_File: openEulter-1-relay-bin.000002 Relay_Log_Pos: 323 Relay_Master_Log_File: binlog.000003 Slave_IO_Running: Yes Slave_SQL_Running: Yes ...... -
从库2配置
[root@openEulter-1 ~]# vim /etc/my.cnf [mysqld] server_id=3 # 重启服务 [root@openEulter-1 ~]# systemctl restart mysqld [root@openEulter-1 ~]# mysql mysql> change master to -> master_host='172.25.254.100', -> master_user='rep', -> master_password='123456', -> master_log_file='binlog.000003', -> master_log_pos=707, -> get_master_public_key=1; # 检验 mysql> start slave; mysql> show slave status \G; *************************** 1. row *************************** Slave_IO_State: Waiting for source to send event Master_Host: 172.25.254.100 Master_User: rep Master_Port: 3306 Connect_Retry: 60 Master_Log_File: binlog.000003 Read_Master_Log_Pos: 707 Relay_Log_File: openEulter-1-relay-bin.000002 Relay_Log_Pos: 323 Relay_Master_Log_File: binlog.000003 Slave_IO_Running: Yes Slave_SQL_Running: Yes ...... -
验证
# 在主库创建数据库db1 mysql> create database db1; # 在两个从库查看数据库 mysql> show databases; +--------------------+ | Database | +--------------------+ | db1 | | information_schema | | mysql | | performance_schema | | sys | +--------------------+
3.基于gtid的主从同步
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主库的配置
[root@openEulter-1 ~]# vim /etc/my.cnf [mysqld] server_id=1 gtid_mode=ON enforce-gtid-consistency=ON [root@openEulter-1 ~]# systemctl restart mysqld # 检测配置 [root@openEulter-1 ~]# mysql mysql> show variables like '%gtid%'; +----------------------------------+-----------+ | Variable_name | Value | +----------------------------------+-----------+ | binlog_gtid_simple_recovery | ON | | enforce_gtid_consistency | ON | | gtid_executed | | | gtid_executed_compression_period | 0 | | gtid_mode | ON | | gtid_next | AUTOMATIC | | gtid_owned | | | gtid_purged | | | session_track_gtids | OFF | +----------------------------------+-----------+ mysql> show master status; +---------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +---------------+----------+--------------+------------------+-------------------+ | binlog.000004 | 157 | | | | +---------------+----------+--------------+------------------+-------------------+ -
从库1的配置
[root@openEulter-1 ~]# vim /etc/my.cnf [mysqld] server_id=2 gtid_mode=ON enforce-gtid-consistency=ON [root@openEulter-1 ~]# systemctl restart mysqld # 检测配置 [root@openEulter-1 ~]# mysql mysql> show variables like '%gtid%'; +----------------------------------+-----------+ | Variable_name | Value | +----------------------------------+-----------+ | binlog_gtid_simple_recovery | ON | | enforce_gtid_consistency | ON | | gtid_executed | | | gtid_executed_compression_period | 0 | | gtid_mode | ON | | gtid_next | AUTOMATIC | | gtid_owned | | | gtid_purged | | | session_track_gtids | OFF | +----------------------------------+-----------+ mysql> change master to -> master_host='172.25.254.100', -> master_user='rep', -> master_password='123456', -> master_auto_position=1; Query OK, 0 rows affected, 7 warnings (0.01 sec) ## mysql8.0.22以后，也可以这么写 mysql> change replication source to -> source_host='172.25.254.100', -> source_user='rep', -> source_password='123456', -> source_auto_position=1; # 检测 mysql> start slave; mysql> show slave status \G *************************** 1. row *************************** Slave_IO_State: Waiting for source to send event Master_Host: 172.25.254.100 Master_User: rep Master_Port: 3306 Connect_Retry: 60 Master_Log_File: binlog.000004 Read_Master_Log_Pos: 157 Relay_Log_File: openEulter-1-relay-bin.000002 Relay_Log_Pos: 367 Relay_Master_Log_File: binlog.000004 Slave_IO_Running: Yes Slave_SQL_Running: Yes ...... -
从库2的配置
[root@openEulter-1 ~]# vim /etc/my.cnf [mysqld] server_id=3 gtid_mode=ON enforce-gtid-consistency=ON [root@openEulter-1 ~]# systemctl restart mysqld # 检测配置 [root@openEulter-1 ~]# mysql mysql> show variables like '%gtid%'; +----------------------------------+-----------+ | Variable_name | Value | +----------------------------------+-----------+ | binlog_gtid_simple_recovery | ON | | enforce_gtid_consistency | ON | | gtid_executed | | | gtid_executed_compression_period | 0 | | gtid_mode | ON | | gtid_next | AUTOMATIC | | gtid_owned | | | gtid_purged | | | session_track_gtids | OFF | +----------------------------------+-----------+ mysql> change master to -> master_host='172.25.254.100', -> master_user='rep', -> master_password='123456', -> master_auto_position=1; Query OK, 0 rows affected, 7 warnings (0.02 sec) # 检测 mysql> start slave; mysql> show slave status \G *************************** 1. row *************************** Slave_IO_State: Waiting for source to send event Master_Host: 172.25.254.100 Master_User: rep Master_Port: 3306 Connect_Retry: 60 Master_Log_File: binlog.000004 Read_Master_Log_Pos: 157 Relay_Log_File: openEulter-1-relay-bin.000002 Relay_Log_Pos: 367 Relay_Master_Log_File: binlog.000004 Slave_IO_Running: Yes Slave_SQL_Running: Yes ...... -
验证
# 在主库创建数据库db2 mysql> create database db2; Query OK, 1 row affected (0.00 sec) # 在从库检验 mysql> show databases; +--------------------+ | Database | +--------------------+ | db1 | | db2 | | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 6 rows in set (0.01 sec)