brief introduction
The so-called "dual master replication" is actually "mutual master-slave replication". That is, each master host has both a master role and a slave role. In this way, the changes made by any party will be replicated to the database of another host through the master and slave to achieve data consistency. This is "dual master replication".
There are two ways of database replication: GTID-based replication; and binary log location-based replication. The former "GTID-based replication" discussed in this article.
System environment
| operating system: | CentOS Linux release 7.4.1708 (Core) |
| Software version: | MySQL 5.6.45 |
| Internet Information: | master-01: 10.10.50.115 |
| master-02: 10.10.50.116 |
Install MySQL service
(Skip, refer to the article "MySQL 5.6 (CentOS 7)" for details)
Configuration service
# On master-01
#!/bin/sh ########################################## ################################### # (0) Create the necessary directories: ##### ############################################## ######################## mkdir -pv /var/log/mysql/ chown mysql.mysql /var/log/mysql/ #### ############################################## ######################### # (1) Modify the /etc/mysql/my.cnf file: #! ! ! Different distributions have different configuration locations, please don't copy them! Please don't copy it! Please don't copy it! ############################################## ############################# mv /etc/mysql/my.cnf /etc/mysql/my.cnf.backup cat <<MYCNF >> /etc/mysql/my.cnf server_id = 1 auto-increment-offset = 1 auto-increment-increment = 2 log_bin = mysql-bin binlog_format = MIXED enforce_gtid_consistency = 1 log_slave_updates = ON gtid_mode = ON MYCNF ################################### ########################################## # (2) Restart the service : ############################################## ############################## systemctl restart mysqld.service
# On master-02
#!/bin/sh ########################################## ################################### # (0) Create the necessary directories: ##### ############################################## ######################## mkdir -pv /var/log/mysql/ chown mysql.mysql /var/log/mysql/ #### ############################################## ######################### # (1) Modify the /etc/mysql/my.cnf file: #! ! ! Different distributions have different configuration locations, please don't copy them! Please don't copy it! Please don't copy it! ############################################## ############################# mv /etc/mysql/my.cnf /etc/mysql/my.cnf.backup cat <<MYCNF >> /etc/mysql/my.cnf server_id = 2 auto-increment-offset = 2 auto-increment-increment = 2 log_bin = mysql-bin binlog_format = MIXED enforce_gtid_consistency = 1 log_slave_updates = ON gtid_mode = ON MYCNF ################################### ########################################## # (2) Restart the service : ############################################## ############################## systemctl restart mysqld.service
Create user for replication
Create users for replication on master-01 and master-02 respectively. After creating a user, don't forget to verify whether the user can log in normally.
# On master-01
GRANT REPLICATION SLAVE ON *.* TO 'replication'@'%' IDENTIFIED BY 'BU3CGK6x';
# On master-02
-- SQL GRANT REPLICATION SLAVE ON *.* TO 'replication'@'%' IDENTIFIED BY 'BU3CGK6x';
Enable replication
Respectively enable replication on master-01 and master-02:
# On master-01
-- SQL --
STOP SLAVE;
CHANGE MASTER TO master_host='10.10.50.116', master_port=3306,
master_user='replication', master_password='BU3CGK6x',
master_auto_position=1;
START SLAVE;
# On master-02
-- SQL --
STOP SLAVE;
CHANGE MASTER TO master_host='10.10.50.115', master_port=3306,
master_user='replication', master_password='BU3CGK6x',
master_auto_position=1;
START SLAVE;
Copy verification
The verification process is not detailed here. Because it is relatively simple, here is only an overview of the idea of verifying whether the copy works:
Create libraries and tables on master-01, and then view them on master-02. Create libraries and tables on master-02, and then view them on master-01.
If there is no problem, there is no problem. If there is no synchronization, you can execute the SHOW SLAVE STATUS \G statement on the database to view the synchronization status and synchronization error information (if any).
Check status
Use SHOW MASTER STATUS \G statement to view your own status; use SHOW SLAVE STATUS \G statement to view your own status as a slave;
related articles
"MySQL"-set up master-slave replication (GTID-based replication)
"MySQL" -dual -master replication (location-based replication)
"MySQL"-set up master-slave replication (location-based replication)
references
Setting up MySQL Master-Slave Replication with GTID
Bug #83713 Slave failed to initialize relay log info after OS crash when use MTS and GTID