MySQL master-slave replication

Introduce

MySQL The database supports master-slave replication by default , Bottom based MySQL The database comes with Binary log Function realization .

Binary log ： Also known as binlog, This is a MySQL A built-in log function , It will record all additions, deletions and modifications , But do not record query statements .

Master slave replication principle ：MySQL The master-slave copy of is actually generated by the master database binlog, It records the user's operations that affect the database . Read the log from the library , And the corresponding SQL sentence , Then execute... On your own server , You can get the data consistent with the main database .

  

MySQL The replication process is divided into three steps ：

1. master Write data changes to binary log

2. slave take master Copy the binary log to its relay log （relay log）

3. slave Redo events in relay log , Generate corresponding data and store it in your own data area

Realization

Realization MySQL Master-slave replication of is actually very simple , Only need to MySQL Simply configure it

① Prepare the server

Prepare two servers in advance , And install... In the server MySQL, The server information is as follows ：

database	IP	Database version
Master	192.168.136.129	5.5.49-log
Slave	192.168.136.130	5.5.49-log

== The first one can be used directly from the previous day , Then reinstall one Linux operating system , Then just deploy on it mysql that will do ==

② Firewall settings

Modify the firewall policies of the two servers respectively , release 3306 port

 firewall-cmd --zone=public --add-port=3306/tcp --permanent
 firewall-cmd --reload
 firewall-cmd --zone=public --list-ports

③ Main library configuration

The following operations are only in master Library to perform [1. Turn on binary log 2. Create an account ]

​​​​​​​# 1.  modify mysql Configuration file for /etc/my.cnf, Ensure the following two 
 [mysqld]
 log-bin=mysql-bin   #[ must ] Enable binary logging ( Currently enabled by default )
 server-id=1         #[ must ] The server is unique ID( The current default is 1)
 ​
 # 2.  restart mysql service 
 systemctl restart mysql
 ​
 # 3.  Sign in mysql
 mysql -uroot -proot
 ​
 # 4.  stay mysql Command line , Create a user for data synchronization and authorize 
 #     This operation will be in mysql Create an account in xiaoming, The password for [email protected], And give xiaoming User grants REPLICATION SLAVE jurisdiction .
 #     It is often used to establish the user permissions required for replication , That is to say slave Must be master Authorize the user with this permission , Can be copied by this user .
 GRANT REPLICATION SLAVE ON *.* to 'xiaoming'@'%' identified by '[email protected]';
 ​
 #  stay mysql Command line , see master sync 
 show master status;

== notes ： The screenshot is Master Current state , After that SQL after , Before the master-slave replication is completed , No more operations ==

④ Configuration from library

The following operations are only in slave Library to perform

 # 1.  modify mysql Configuration file for /etc/my.cnf, Ensure the following two 
 [mysqld]
 log-bin=mysql-bin   #[ must ] Enable binary logging ( Currently enabled by default )
 server-id=2         #[ must ] The server is unique ID( Current default 1, It must be manually modified to 2)
 ​
 # 2.  restart mysql service 
 systemctl restart mysql
 ​
 # 3.  Sign in mysql
 mysql -uroot -proot
 ​
 # 4.  stay mysql Command line , Perform the operation of replication 
 #     Be careful , The parameters in this command , It needs to be modified according to the actual situation 
 change master to  
     master_host='192.168.136.129', --  Master node ip Address 
     master_user='xiaoming', --  The account created by the master node for master-slave replication 
     master_password='[email protected]', --  The password of the account above 
     master_log_file='mysql-bin.000002', --  Which log file to synchronize from the master node 
     master_log_pos=258; --  Where to start synchronization from the log file of the primary node 
     
 # 5.  stay mysql Command line , Start the copy operation 
 #    start-up I/O Thread read from main library binlog, And store it to relaylog In the relay log file .
 #    start-up SQL Thread read relay log , After parsing, replay from the Library . 
 start slave; 
 ​
 # 6.  stay mysql Command line , Check the status of master-slave replication 
 show slave status\G;

This one's inside   There's a caveat , Don't write nonsense , Just go straight up and down .

  Get this result , It means you are successful

 

test

Only this and nothing more , The master-slave replication environment has been set up , Next , We can connect two MySQL The server tests .

When testing , We just need to be in the main library Master Perform the operation , View from library Slave Whether to synchronize the data in the past .

① stay master Create database itcast, Refresh slave See if you can sync the past

② stay master Of itcast Create... Under data user surface , Refresh slave See if you can sync the past

 

③ stay master Of user Insert a piece of data into the table , Refresh slave See if you can sync the past