前言：
在数据驱动的现代应用中，数据库面临高并发读写与海量存储的双重挑战。单一数据库实例在性能、可用性及扩展性上逐渐成为瓶颈。MySQL主从复制（Master-Slave Replication）与读写分离（Read/Write Splitting）通过分布式架构，将写操作集中于主库（Master），读操作分发至多个从库（Slave），辅以基于二进制日志（Binlog）的异步/半同步数据同步机制，实现了数据冗余、负载分流与故障快速恢复。这一架构不仅成为企业级数据库高可用的基石，更为业务提供了弹性扩展的底层支撑。
目录
[(1) 在 主服务器 上操作：](#(1) 在 主服务器 上操作：)
[(2) 在 从服务器 上验证同步：](#(2) 在 从服务器 上验证同步：)
[(1) 模拟主库故障：](#(1) 模拟主库故障：)
[(2) 检查MaxScale状态：](#(2) 检查MaxScale状态：)
[(3) 验证新主库写入：](#(3) 验证新主库写入：)
[(4) 恢复旧主库并检查同步：](#(4) 恢复旧主库并检查同步：)
一、概述
1、master开启二进制日志记录
2、slave开启IO进程，从master中读取二进制日志并写入slave的中继日志
3、slave开启SQL进程，从中继日志中读取二进制日志并进行重放
4、最终，达到slave与master中数据一致的状态，我们称作为主从复制的过程。
二、基础环境设置
网络对时
主与从主机都需要操作
[root@ryan ~]# cat /etc/chrony.conf | grep -Ev '^$|#'
server ntp.aliyun.com iburst ###添加或者修改
driftfile /var/lib/chrony/drift
makestep 1.0 3
rtcsync
keyfile /etc/chrony.keys
leapsectz right/UTC
logdir /var/log/chrony
###切换到主
[root@master ~]# timedatectl set-timezone Asia/Shanghai
[root@master mysql]# vim /etc/chrony.conf
[root@master mysql]# systemctl restart chronyd.service
[root@master mysql]# date
2025年 07月 06日 星期日 17:25:50 CST
###切换到从
[root@slave ~]# timedatectl set-timezone Asia/Shanghai
[root@slave ~]# vim /etc/chrony.conf 
[root@slave ~]# systemctl restart chronyd.service
[root@slave ~]# date
2025年 07月 06日 星期日 17:29:59 CST防火墙与SELinux
主与从主机都需要操作
###主
[root@master ~]# systemctl disable --now firewalld
[root@master ~]# setenforce 0
[root@master ~]# getenforce
Permissive
###从
[root@slave ~]# systemctl disable --now firewalld
[root@slave ~]# setenforce 0
[root@slave ~]# getenforce
Permissive三、配置主从复制
主服务配置
##修改配置文件
[root@localhost ~]# cat /etc/my.cnf
#
# This group is read both both by the client and the server
# use it for options that affect everything
#
[mysqld]
log-bin=mysql-bin
binlog_format="statement"
server-id=11
log-slave-updates=true
[client-server]
#
# include all files from the config directory
#
!includedir /etc/my.cnf.d
##启动服务
[root@localhost ~]# systemctl enable --now mysqld
#验证配置
[root@localhost ~]# cd /var/lib/mysql/
[root@localhost mysql]# ls
auto.cnf client-cert.pem ibdata1 mysql-bin.000003 mysql_upgrade_info server-key.pem
binlog.000001 client-key.pem ibtmp1 mysql-bin.000004 mysqlx.sock sys
binlog.000002 db1 '#innodb_redo' mysql-bin.000005 mysqlx.sock.lock undo_001
binlog.index db2 '#innodb_temp' mysql-bin.index performance_schema undo_002
c2407 '#ib_16384_0.dblwr' mysql mysql.ibd private_key.pem
ca-key.pem '#ib_16384_1.dblwr' mysql-bin.000001 mysql.sock public_key.pem
ca.pem ib_buffer_pool mysql-bin.000002 mysql.sock.lock server-cert.pem
##创建从主机可以进行访问的用户
mysql> create user slave@'192.168.72.%' identified by '123.com';
mysql> grant all on *.* to 'slave'@'192.168.72.%';
###密码插件修改
ALTER USER 'slave'@'192.168.166.%' IDENTIFIED WITH mysql_native_password BY '123.com';
###查看master正在使用的日志文件及日志书写位置
[root@localhost mysql]# mysql
mysql> show master status;
+-------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+-------------------+----------+--------------+------------------+
| master-bin.000003 | 542 | | |
+-------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
#注意：查看位置完毕后，不要对master做insert、update、delete、create、drop等操作！！！
[root@master ~]# systemctl restart mysqld
从服务器配置
##修改配置文件
[root@localhost ~]# cat /etc/my.cnf
relay-log-index=slave-bin.index
server-id=22
##启动服务
[root@localhost ~]# systemctl enable --now mysqld
##配置验证，此时没有与主服务器进行连接，所以没有产生对应的relay log
[root@localhost mysql]# ls
aria_log.00000001 aria_log_control ibdata1 ib_logfile0 ib_logfile1 mysql mysql.sock performance_schema test
##配置从服务器的所属主服务器
[root@localhost mysql]# mysql
mysql> change master to master_host='192.168.158.4',master_user='slave',master_password='123.com',master_log_file='master-bin.000001',master_log_pos=619;
##启动slave角色，默认没有配置主从时，所有的mysql节点都是master
mysql> start slave;
##查看slave状态信息
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for source to send event
Master_Host: 192.168.166.230
Master_User: slave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000005
Read_Master_Log_Pos: 2567
Relay_Log_File: slave-bin.000004
Relay_Log_Pos: 1679
Relay_Master_Log_File: mysql-bin.000005
Slave_IO_Running: Yes
Slave_SQL_Running: 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: 2567
Relay_Log_Space: 2416
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: 11
Master_UUID: 25105bd5-6fd8-11ef-9dae-000c299fb683
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Replica 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:
Master_public_key_path:
Get_master_public_key: 0
Network_Namespace:
1 row in set, 1 warning (0.00 sec)
#查看数据目录
[root@localhost mysql]# ls
aria_log.00000001 ibdata1 ib_logfile1 mysql performance_schema slave-bin.000001 slave-bin.index
aria_log_control ib_logfile0 master.info mysql.sock relay-log.info slave-bin.000002 test
[root@slave ~]# vim /etc/my.cnf.d/mysql-server.cnf 
[root@slave mysql]# systemctl restart mysqld配置从服务器的所属主服务器
开启同步
mysql> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for source to send event
Master_Host: 192.168.72.155
Master_User: slave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000010
Read_Master_Log_Pos: 589
Relay_Log_File: slave-relay-bin.000014
Relay_Log_Pos: 326
Relay_Master_Log_File: mysql-bin.000010
Slave_IO_Running: Yes
Slave_SQL_Running: 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: 589
Relay_Log_Space: 885
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: 11
Master_UUID: a0e533b0-51d8-11f0-a49f-000c2939f194
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Replica 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:
Master_public_key_path:
Get_master_public_key: 0
Network_Namespace:
1 row in set, 1 warning (0.00 sec)
ERROR:
No query specified验证
从查看不到任何库
切换到主创建新库
切换到从查看到主新创建的库
从查看二进制日志主创建指令是否同步
[root@slave ~]# cd /var/lib/mysql
[root@slave mysql]# ls
auto.cnf ca.pem '#innodb_temp' public_key.pem
binlog.000001 client-cert.pem mysql server-cert.pem
binlog.000002 client-key.pem mysql.ibd server-key.pem
binlog.000003 gooddays mysql.sock slave-bin.index
binlog.000004 '#ib_16384_0.dblwr' mysql.sock.lock slave-relay-bin.000001
binlog.000005 '#ib_16384_1.dblwr' mysql_upgrade_info slave-relay-bin.000002
binlog.000006 ib_buffer_pool mysqlx.sock sys
binlog.000007 ibdata1 mysqlx.sock.lock undo_001
binlog.index ibtmp1 performance_schema undo_002
ca-key.pem '#innodb_redo' private_key.pem
[root@slave mysql]# mysqlbinlog slave-relay-bin.000002
主从复制常见问题
异常：
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Connecting to source
Master_Host: 192.168.166.230
Master_User: slave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000005
Read_Master_Log_Pos: 2567
Relay_Log_File: slave-bin.000004
Relay_Log_Pos: 1679
Relay_Master_Log_File: mysql-bin.000005
Slave_IO_Running: Connecting
Slave_SQL_Running: 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: 2567
Relay_Log_Space: 2416
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: NULL
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 2003
Last_IO_Error: Error connecting to source 'slave@192.168.166.230:3306'. This was attempt 1/86400, with a delay of 60 seconds between attempts. Message: Can't connect to MySQL server on '192.168.166.230:3306' (113)
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 11
Master_UUID: 25105bd5-6fd8-11ef-9dae-000c299fb683
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Replica has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp: 240913 04:04:49
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:
Master_public_key_path:
Get_master_public_key: 0
Network_Namespace:
1 row in set, 1 warning (0.00 sec)一般情况下，都与网络通信异常有关系。排查防火墙、物理网络连接等。二进制日志文件名或位置错误也会引起IO线程异常。
reset replica;
##用于重置SQL线程对relay log的重放记录！！四、maxscale概述
MaxScale是maridb开发的一个mysql数据中间件，其配置简单，能够实现读写分离，并且可以根据主从状态实现写库的自动切换。 官网：https://mariadb.com/kb/en/mariadb-enterprise/mariadb-maxscale-20/
下载地址：https://dlm.mariadb.com/3927179/MaxScale/24.02.3/rhel/9/x86_64/maxscale-24.02.3-1.rhel.9.x86_64.rpm
https://dlm.mariadb.com/3993858/MaxScale/24.02.4/rhel/8/x86_64/maxscale-24.02.4-1.rhel.8.x86_64.rpm
五、读写分离
1、环境说明
| 数据库角色 | IP | 应用与系统版本 |
|---|---|---|
| master | 192.168.166.25 | rocky linux9.4 mysql-8.0.36 |
| slave | 192.168.166.26 | rocky linux9.4 mysql-8.0.36 |
| slave2 | 192.168.166.27 | rocky linux9.4 mysql-8.0.36 |
| maxscale | 192.168.166.9 | rocky linux9.4 maxscale24.02.3-GA |
主带从
主服务器 (Master): server1 (192.168.72.155:3366)
从服务器 (Slave): server2 (192.168.72.129:3366)
maxscale 192.168.72.9
2、mysql主从复制配置
分别在主从三台服务器上安装mysql8，并配置主从复制。
##由于认证插件问题，需要在master服务器使用下述命令进行更改密码的验证插件。
ALTER USER'slave'@'%' IDENTIFIED WITH mysql_native_password BY 'password';
FLUSH PRIVILEGES;
###修改认证插件
##my.cnf
default-authentication-plugin=mysql_native_password主配置
[root@master mysql]# vim /etc/my.cnf.d/mysql-server.cnf 
[root@master mysql]# systemctl restart mysqld从配置
[root@master slave]# vim /etc/my.cnf.d/mysql-server.cnf 
[root@master slave]# systemctl restart mysqld从查看同步状态是否正常
3、maxscale安装
#下载yum源
[root@maxscale ~]# curl -LsS https://r.mariadb.com/downloads/mariadb_repo_setup | sudo bash
# [info] Checking for script prerequisites.
# [info] MariaDB Server version 11.2 is valid
# [info] Repository file successfully written to /etc/yum.repos.d/mariadb.repo
# [info] Adding trusted package signing keys...
/etc/pki/rpm-gpg ~
~
# [info] Successfully added trusted package signing keys
# [info] Cleaning package cache...
25 files removed
[root@maxscale ~]# ls /etc/yum.repos.d/
mariadb.repo rocky-addons.repo rocky-devel.repo rocky-extras.repo rocky.repo
#安装maxscale
[root@maxscale ~]# yum -y install maxscalerpm安装
拖入maxscale软件包
直接解决依赖下载
[root@maxscale ~]# rpm -ivh maxscale-24.02.3-1.rhel.9.x86_64.rpm
警告：maxscale-24.02.3-1.rhel.9.x86_64.rpm: 头V4 RSA/SHA512 Signature, 密钥 ID e3c94f49: NOKEY
错误：依赖检测失败：
libmicrohttpd.so.12()(64bit) 被 maxscale-24.02.3-1.rhel.9.x86_64 需要
libodbc.so.2()(64bit) 被 maxscale-24.02.3-1.rhel.9.x86_64 需要
librdkafka++.so.1()(64bit) 被 maxscale-24.02.3-1.rhel.9.x86_64 需要
librdkafka.so.1()(64bit) 被 maxscale-24.02.3-1.rhel.9.x86_64 需要
nodejs >= 10.0.0 被 maxscale-24.02.3-1.rhel.9.x86_64 需要
[root@maxscale ~]# ls
公共 视频 文档 音乐 anaconda-ks.cfg nohup.out
模板 图片 下载 桌面 maxscale-24.02.3-1.rhel.9.x86_64.rpm
[root@maxscale ~]# yum localinstall -y maxscale-24.02.3-1.rhel.9.x86_64.rpm4、配置maxscale
登录到主库
[root@master ~]# mysql -uroot
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 14
Server version: 8.0.36 MySQL Community Server - GPL
Copyright (c) 2000, 2023, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
#创建maxscale用户密码是maxscale
mysql> CREATE USER 'maxscale'@'%' IDENTIFIED BY 'maxscale';
Query OK, 0 rows affected (0.00 sec)
#授权maxscale可以查询所有数据库
mysql> GRANT SELECT ON mysql.* TO 'maxscale'@'%';
Query OK, 0 rows affected (0.01 sec)
#授权可以看所有数据库
mysql> GRANT SHOW DATABASES ON *.* TO 'maxscale'@'%';
Query OK, 0 rows affected (0.00 sec)
#创建admin用户可以在maxscale上登录
mysql> CREATE USER 'admin'@'192.168.166.%' IDENTIFIED BY 'admin';
Query OK, 0 rows affected (0.01 sec)主创建账户
从打开二进制日志查看主创建用户指令
[root@slave ~]# cd -
/var/lib/mysql
[root@slave mysql]# ls
auto.cnf ca.pem mysql server-key.pem
binlog.000001 client-cert.pem mysql.ibd slave-bin.index
binlog.000002 client-key.pem mysql.sock slave-relay-bin.000004
binlog.000003 gooddays mysql.sock.lock slave-relay-bin.000005
binlog.000004 '#ib_16384_0.dblwr' mysql_upgrade_info slave-relay-bin.000006
binlog.000005 '#ib_16384_1.dblwr' mysqlx.sock sys
binlog.000006 ib_buffer_pool mysqlx.sock.lock undo_001
binlog.000007 ibdata1 performance_schema undo_002
binlog.000008 ibtmp1 private_key.pem
binlog.index '#innodb_redo' public_key.pem
ca-key.pem '#innodb_temp' server-cert.pem
[root@slave mysql]# mysqlbinlog slave-relay-bin.000006
从打开数据库查看主是否完成数据同步
切换到主给maxcale赋予所有权限
切换到从进行验证权限是否赋予成功
切换到主创建admin账户
切换到从进行验证
在maxscale上安装mysql
[root@maxscale ~]# yum -y install mysql
[root@maxscale ~]# which mysql
/usr/bin/mysql
#登录到master
[root@maxscale ~]# mysql -uadmin -padmin -h192.168.166.25
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 15
Server version: 8.0.36 MySQL Community Server - GPL
Copyright (c) 2000, 2023, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
###因为没有权限所以只能看到两个数据库
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| performance_schema |
+--------------------+
2 rows in set (0.00 sec)
mysql> exit
Bye
回到master主库设置增删改查权限
mysql> GRANT CREATE, SELECT, INSERT, UPDATE, DELETE ON *.* TO 'admin'@'192.168.72.%';
Query OK, 0 rows affected (0.00 sec)
在master主库上授权真机有增删改查权限
mysql> CREATE USER 'admin'@'192.168.166.%' IDENTIFIED BY 'admin';
Query OK, 0 rows affected (0.01 sec)
mysql> GRANT CREATE, SELECT, INSERT, UPDATE, DELETE ON *.* TO 'admin'@'192.168.72.%';
Query OK, 0 rows affected (0.01 sec)
此时再切回到maxscale主机上可以看到所有库
在maxscale上修改配置文件
[root@maxscale ~]# vim /etc/maxscale.cnf
#先看有无这个
[maxscale]
threads=auto
#修改后端服务器地址
[server1]
type=server
address=192.168.166.25
port=3306
protocol=MySQLBackend
[server2]
type=server
address=192.168.166.26
port=3306
protocol=MySQLBackend
[server3]
type=server
address=192.168.166.27
port=3306
protocol=MySQLBackend
#配置监控
[MySQL-Monitor]
type=monitor
module=mariadbmon
servers=server1,server2,server3
user=monitor
password=monitor
monitor_interval=2s
#注释掉只读配置
#[Read-Only-Service]
#type=service
#router=readconnroute
#servers=server2
#user=maxscale
#password=maxscale
#router_options=slave
#修改读写分离服务
[Read-Write-Service]
type=service
router=readwritesplit
servers=server1,server2,server3
user=maxscale
password=maxscale
version_string = 8.0
#配置listener
#注释掉只读
#[Read-Only-Listener]
#type=listener
#service=Read-Only-Service
#protocol=mariadbprotocol
#port=4008
#修改读写分离
[Read-Write-Listener]
type=listener
service=Read-Write-Service
protocol=mariadbprotocol
port=3306 #(伪装成数据库端口3306)
[root@maxscale maxscale]# cat /etc/maxscale.cnf
#####################################################
# MaxScale documentation: #
# https://mariadb.com/kb/en/mariadb-maxscale-24-02/ #
#####################################################
#######################################################################################################
# Global parameters #
# #
# Complete list of configuration options: #
# https://mariadb.com/kb/en/mariadb-maxscale-2402-maxscale-2402-mariadb-maxscale-configuration-guide/ #
#######################################################################################################
[maxscale]
threads=auto
############################################################################
# Server definitions #
# #
# Set the address of the server to the network address of a MariaDB server.#
############################################################################
[server1]
type=server
address=192.168.72.155
port=3306
protocol=MySQLBackend
[server2]
type=server
address=192.168.72.129
port=3306
protocol=MySQLBackend
##################################################################################
# Uncomment this and add MaxScale's IP to proxy_protocol_networks in MariaDB for #
# easier user management: https://mariadb.com/kb/en/proxy-protocol-support/ #
##################################################################################
# proxy_protocol=true
##################################################################################################
# Monitor for the servers #
# #
# This will keep MaxScale aware of the state of the servers. #
# MariaDB Monitor documentation: #
# https://mariadb.com/kb/en/maxscale-24-02monitors/ #
# #
# The GRANTs needed by the monitor user depend on the actual monitor. #
# The GRANTs required by the MariaDB Monitor can be found here: #
# https://mariadb.com/kb/en/mariadb-maxscale-2402-maxscale-2402-mariadb-monitor/#required-grants #
##################################################################################################
[MySQL-Monitor]
type=monitor
module=mariadbmon
servers=server1,server2
user=monitor
password=monitor
monitor_interval=2s
##################################################################################################################
# Uncomment these to enable automatic node failover: #
# https://mariadb.com/kb/en/mariadb-maxscale-2402-maxscale-2402-mariadb-monitor/#cluster-manipulation-operations #
# #
# The GRANTs required for automatic node failover can be found here: #
# https://mariadb.com/kb/en/mariadb-maxscale-2402-maxscale-2402-mariadb-monitor/#cluster-manipulation-grants #
##################################################################################################################
# auto_failover=true
# auto_rejoin=true
# enforce_simple_topology=true
# replication_user=<username used for replication>
# replication_password=<password used for replication>
#########################################################################################################
# Uncomment this if you use more than one MaxScale with automatic node failover: #
# https://mariadb.com/kb/en/mariadb-maxscale-2402-maxscale-2402-mariadb-monitor/#cooperative-monitoring #
#########################################################################################################
# cooperative_monitoring_locks=majority_of_all
#########################################################################################################
# Service definitions #
# #
# Service Definition for a read-only service and a read/write splitting service. #
# #
# The GRANTs needed by the service user can be found here: #
# https://mariadb.com/kb/en/mariadb-maxscale-2402-maxscale-2402-authentication-modules/#required-grants #
#########################################################################################################
################################################################################
# ReadConnRoute documentation: #
# https://mariadb.com/kb/en/mariadb-maxscale-2402-maxscale-2402-readconnroute/ #
################################################################################
#[Read-Only-Service]
#type=service
#router=readconnroute
#servers=server1
#user=service_user
#password=service_pw
#router_options=slave
#################################################################################
# ReadWriteSplit documentation: #
# https://mariadb.com/kb/en/mariadb-maxscale-2402-maxscale-2402-readwritesplit/ #
#################################################################################
[Read-Write-Service]
type=service
router=readwritesplit
servers=server1,server2
user=maxscale
password=maxscale
version_string = 8.0
####################################################################################################
# Uncomment these to enable transparent transaction replay on node failure: #
# https://mariadb.com/kb/en/mariadb-maxscale-2402-maxscale-2402-readwritesplit/#transaction_replay #
####################################################################################################
# transaction_replay=true
# transaction_replay_timeout=30s
####################################################################
# Listener definitions for the services #
# #
# These listeners represent the ports the services will listen on. #
####################################################################
#[Read-Only-Listener]
#type=listener
#service=Read-Only-Service
#port=4008
[Read-Write-Listener]
type=listener
service=Read-Write-Service
protocol=mariadbprotocol
port=3306切换到maxcale做备份并修改配置文件
[root@maxscale ~]# mv /etc/maxscale.cnf /opt/maxscale.cnf.bak
[root@maxscale ~]# ls -l /etc/maxscale.cnf
-rw-r--r--. 1 root root 779 7月 6 19:51 /etc/maxscale.cnf
[root@maxscale ~]# ls -l /etc/maxscale.cnf.d/ -d
drwxr-xr-x. 2 maxscale maxscale 6 9月 7 2024 /etc/maxscale.cnf.d/
[root@maxscale ~]# chown maxscale.maxscale /etc/maxscale.cnf
[root@maxscale ~]# vim /etc/maxscale.cnf
切换到主库创建monitor监控用户
mysql> CREATE USER 'monitor'@'%' IDENTIFIED BY 'monitor';
Query OK, 0 rows affected (0.01 sec)
#再添加授权
mysql> GRANT REPLICATION CLIENT on *.* to 'monitor'@'%';
Query OK, 0 rows affected (0.00 sec)
mysql> GRANT REPLICATION SLAVE on *.* to 'monitor'@'%';
Query OK, 0 rows affected (0.01 sec)
mysql> GRANT SUPER,RELOAD on *.* to 'monitor'@'%';
Query OK, 0 rows affected, 1 warning (0.01 sec)
启动服务
[root@maxscale ~]# systemctl start maxscale
[root@maxscale maxscale]# systemctl status maxscale
● maxscale.service - MariaDB MaxScale Database Proxy
Loaded: loaded (/usr/lib/systemd/system/maxscale.service; enabled; preset: >
Active: active (running) since Sun 2025-07-06 20:15:20 CST; 5min ago
Process: 18138 ExecStartPre=/usr/bin/install -d /var/cache/maxscale -o maxsc>
Process: 18139 ExecStart=/usr/bin/maxscale (code=exited, status=0/SUCCESS)
Main PID: 18141 (maxscale)
Tasks: 12 (limit: 22799)
Memory: 8.0M
CPU: 287ms
CGroup: /system.slice/maxscale.service
└─18141 /usr/bin/maxscale
7月 06 20:15:17 maxscale systemd[1]: Starting MariaDB MaxScale Database Proxy...
7月 06 20:15:17 maxscale maxscale[18141]: Module 'mariadbmon' loaded from '/usr/>
7月 06 20:15:17 maxscale maxscale[18141]: Module 'readwritesplit' loaded from '/>
lines 1-15...skipping...
● maxscale.service - MariaDB MaxScale Database Proxy
Loaded: loaded (/usr/lib/systemd/system/maxscale.service; enabled; preset: disabled)
Active: active (running) since Sun 2025-07-06 20:15:20 CST; 5min ago
Process: 18138 ExecStartPre=/usr/bin/install -d /var/cache/maxscale -o maxscale -g maxscale (code=exited, status=0/SUCCESS)
Process: 18139 ExecStart=/usr/bin/maxscale (code=exited, status=0/SUCCESS)
Main PID: 18141 (maxscale)
Tasks: 12 (limit: 22799)
Memory: 8.0M
CPU: 287ms
CGroup: /system.slice/maxscale.service
└─18141 /usr/bin/maxscale
7月 06 20:15:17 maxscale systemd[1]: Starting MariaDB MaxScale Database Proxy...
7月 06 20:15:17 maxscale maxscale[18141]: Module 'mariadbmon' loaded from '/usr/lib64/maxscale/libmariadbmon.so'.
7月 06 20:15:17 maxscale maxscale[18141]: Module 'readwritesplit' loaded from '/usr/lib64/maxscale/libreadwritesplit.so'.
7月 06 20:15:17 maxscale maxscale[18141]: Using up to 543.91MiB of memory for query classifier cache
7月 06 20:15:20 maxscale systemd[1]: Started MariaDB MaxScale Database Proxy.查看端口
[root@maxscale ~]# ss -antl
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
LISTEN 0 4096 127.0.0.1:8989 0.0.0.0:*
LISTEN 0 128 0.0.0.0:22 0.0.0.0:*
LISTEN 0 4096 *:3306 *:*
LISTEN 0 128 [::]:22 [::]:*
[root@maxscale ~]# ss -antlp
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
LISTEN 0 4096 127.0.0.1:8989 0.0.0.0:* users:(("maxscale",pid=15450,fd=19))
LISTEN 0 128 0.0.0.0:22 0.0.0.0:* users:(("sshd",pid=792,fd=3))
LISTEN 0 4096 *:3306 *:* users:(("maxscale",pid=15450,fd=27))
LISTEN 0 128 [::]:22 [::]:* users:(("sshd",pid=792,fd=4)) 查看有哪些服务
[root@maxscale ~]# maxctrl list services
┌────────────────────┬────────────────┬─────────────┬───────────────────┬───────────────────────────┐
│ Service │ Router │ Connections │ Total Connections │ Targets │
├────────────────────┼────────────────┼─────────────┼───────────────────┼───────────────────────────┤
│ Read-Write-Service │ readwritesplit │ 0 │ 0 │ server1, server2, server3 │
└────────────────────┴────────────────┴─────────────┴───────────────────┴───────────────────────────┘
验证
检查路由服务状态
[root@maxscale maxscale]# maxctrl list services
[root@maxscale maxscale]# maxctrl list monitors
查看后台服务器有哪些
[root@maxscale ~]# maxctrl list servers
┌─────────┬─────────────────┬──────┬─────────────┬─────────────────┬──────┬───────────────┐
│ Server │ Address │ Port │ Connections │ State │ GTID │ Monitor │
├─────────┼─────────────────┼──────┼─────────────┼─────────────────┼──────┼───────────────┤
│ server1 │ 192.168.166.25 │ 3306 │ 0 │ Master, Running │ │ MySQL-Monitor │
├─────────┼─────────────────┼──────┼─────────────┼─────────────────┼──────┼───────────────┤
│ server2 │ 192.168.166.27 │ 3306 │ 0 │ Slave, Running │ │ MySQL-Monitor │
├─────────┼─────────────────┼──────┼─────────────┼─────────────────┼──────┼───────────────┤
│ server3 │ 192.168.166.26 │ 3306 │ 0 │ Slave, Running │ │ MySQL-Monitor │
└─────────┴─────────────────┴──────┴─────────────┴─────────────────┴──────┴───────────────┘实现一主一从 
验证主从同步状态
在 从服务器 上检查复制状态：
SHOW SLAVE STATUS\G关键检查项：
-
Slave_IO_Running: Yes -
Slave_SQL_Running: Yes -
Seconds_Behind_Master: 0（表示无延迟） -
无错误信息（
Last_IO_Error/Last_SQL_Error为空）
1.测试数据同步
(1) 在 主服务器 上操作：
-- 创建测试数据库
CREATE DATABASE sync_test;
USE sync_test;
-- 创建测试表
CREATE TABLE test_data (
id INT AUTO_INCREMENT PRIMARY KEY,
message VARCHAR(50),
created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
-- 插入测试数据
INSERT INTO test_data (message) VALUES ('Data from Master');(2) 在 从服务器 上验证同步：
USE sync_test;
SELECT * FROM test_data; -- 应看到主库插入的数据2.测试读写分离（通过MaxScale）
假设MaxScale的读写分离端口为 4000（需确认实际端口）：
# 通过MaxScale写入（应路由到主库）
mysql -h <MaxScale_IP> -P 4000 -u user -p -e "INSERT INTO sync_test.test_data (message) VALUES ('Via MaxScale')"
# 通过MaxScale读取（应路由到从库）
mysql -h <MaxScale_IP> -P 4000 -u user -p -e "SELECT * FROM sync_test.test_data"预期结果：
-
写入操作在 主服务器 可见
-
读取结果包含所有数据（包括新插入的
Via MaxScale）
3.故障切换测试
(1) 模拟主库故障：
# 停止主库MySQL服务（在server1执行）
systemctl stop mysql(2) 检查MaxScale状态：
maxctrl list servers预期变化：
-
server1 状态变为
Down -
server2 自动提升为
Master
(3) 验证新主库写入：
-- 通过MaxScale写入（应路由到新的主库server2）
INSERT INTO sync_test.test_data (message) VALUES ('New Master Write');(4) 恢复旧主库并检查同步：
# 重启server1的MySQL
systemctl start mysql
# 在server1上重新配置为从库
CHANGE MASTER TO
MASTER_HOST='192.168.72.129', -- 指向新主库server2
MASTER_PORT=3366,
MASTER_USER='repl_user',
MASTER_PASSWORD='password';
START SLAVE;关键命令总结
| 操作 | 命令 |
|---|---|
| 检查复制状态 | SHOW SLAVE STATUS\G |
| 强制切换主库 | maxctrl call command mariadbmon failover MySQL-Monitor |
| 查看服务器状态 | maxctrl list servers |
| 验证数据同步 | 主库写入 → 从库查询 |
注意：实际测试前请确认：
MaxScale配置文件中定义的读写分离端口（
[RW Split Router]）数据库账号需有复制权限（主从同步）和远程访问权限（MaxScale连接）
测试
用客户机连接maxscale
username：admin
password：admin会发现进行读操作时，是在slave的从数据库上执行；在进行写操作时，是在master主数据库上执行
总结：
MySQL主从复制与读写分离的核心价值可归纳为以下三点：
- 性能与扩展性提升
- 通过读写分离，将读请求分散到多个从库，显著降低主库压力，支撑高并发查询场景（如电商、社交平台）；
- 横向扩展从库数量可应对业务增长，避免单机硬件瓶颈。
- 高可用与数据安全
- 主库故障时，从库可快速切换为新主库（Failover），保障服务连续性；
- 从库作为实时数据备份，防止主库数据丢失。
- 架构灵活性与成本优化
- 支持异步复制（默认）、半同步复制（平衡安全与延迟）及混合复制模式（MIXED），适应不同业务一致性要求；
- 通过中间件（如MyCat、MySQL Router）实现透明路由，减少应用层改造成本。
需规避的风险与优化方向：
- 数据延迟：异步复制可能因网络或从库性能导致同步延迟，可通过半同步复制、并行处理或优化网络缓解；
- 单点故障：建议采用双主复制或级联架构增强容灾能力；
- 一致性校验 ：定期使用工具（如
pt-table-checksum）检测主从数据差异，避免逻辑冲突。
复制模式对比
类型 数据安全性 延迟 适用场景 异步复制 低 低 高性能场景（默认） 8 半同步复制 中 中 交易类业务 5 11 全同步复制 高 高 强一致性需求 5
未来分布式数据库（如NewSQL）可能逐步替代传统架构，但现阶段MySQL主从复制与读写分离仍是平衡性能、成本与稳定性的最优解。