17.1 MySQL主从介绍
MySQL主从又叫做Replication、AB复制。简单讲就是A和B两台机器做主从后，在A上写数据，另外一台B也会跟着写数据，两者数据实时同步的
MySQL主从是基于binlog的，主上须开启binlog才能进行主从。
主从过程大致有3个步骤
1）主将更改操作记录到binlog里
2）从将主的binlog事件(sql语句)同步到从本机上并记录在relaylog里
3）从根据relaylog里面的sql语句按顺序执行
主上有一个log dump线程，用来和从的I/O线程传递binlog
从上有两个线程，其中I/O线程用来同步主的binlog并生成relaylog，另外一个SQL线程用来把relaylog里面的sql语句落地
两个场景：
1，从作为数据备份
2，不仅仅备份，主上写，从上读，减轻主的压力
17.2 准备工作
从机器上安装 mysql：
[root@arslinux-02 src]# wget http://mirrors.163.com/mysql/Downloads/MySQL-5.6/mysql-5.6.43-linux-glibc2.12-x86_64.tar.gz[root@arslinux-02 src]# tar xvf mysql-5.6.43-linux-glibc2.12-x86_64.tar.gz[root@arslinux-02 src]# mv mysql-5.6.43-linux-glibc2.12-x86_64/ /usr/local/mysql
[root@arslinux-02 mysql]# useradd mysql[root@arslinux-02 mysql]# mkdir /data/[root@arslinux-02 mysql]# mkdir /data/mysql/
[root@arslinux-02 mysql]# ./scripts/mysql_install_db --user=mysql --datadir=/data/mysql/
[root@arslinux-02 mysql]# vim /etc/my.cnf[mysqld]datadir=/data/mysqlsocket=/tmp/mysql.sock
[root@arslinux-02 mysql]# cp support-files/mysql.server /etc/init.d/mysqld[root@arslinux-02 mysql]# vim /etc/init.d/mysqldbasedir=/usr/local/mysqldatadir=/data/mysql
[root@arslinux-02 mysql]# /etc/init.d/mysqld startStarting MySQL. SUCCESS![root@arslinux-02 mysql]# ps aux|grep mysqldroot 7488 0.1 0.1 113312 1616 pts/0 S 16:56 0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/arslinux-02.pidmysql 7652 8.7 45.1 1302736 449792 pts/0 Sl 16:56 0:00 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/var/log/mysql.log --pid-file=/data/mysql/arslinux-02.pid --socket=/tmp/mysql.sockroot 7676 0.0 0.0 112724 984 pts/0 R+ 16:57 0:00 grep --color=auto mysqld[root@arslinux-02 mysql]# netstat -lntpActive Internet connections (only servers)Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program nametcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1/systemdtcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 6926/sshdtcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 7061/mastertcp6 0 0 :::3306 :::* LISTEN 7652/mysqldtcp6 0 0 :::111 :::* LISTEN 1/systemdtcp6 0 0 :::22 :::* LISTEN 6926/sshdtcp6 0 0 ::1:25 :::* LISTEN 7061/master
[root@arslinux-02 mysql]# chkconfig mysqld on[root@arslinux-02 mysql]# chkconfig --list注：该输出结果只显示 SysV 服务，并不包含原生 systemd 服务。SysV 配置数据可能被原生 systemd 配置覆盖。要列出 systemd 服务，请执行 'systemctl list-unit-files'。查看在具体 target 启用的服务请执行'systemctl list-dependencies [target]'。mysqld 0:关1:关2:开3:开4:开5:开6:关netconsole 0:关1:关2:关3:关4:关5:关6:关network 0:关1:关2:开3:开4:开5:开6:关
安装过程参考：
17.3 配置主
修改 my.cnf，增加 server-id（可以根据ip来定），log_bin（logbin的前缀）
[root@arslinux-01 mysql]# vim /etc/my.cnfserver-id = 130log_bin = arselinux
重启 mysql
[root@arslinux-01 ~]# /etc/init.d/mysqld restartShutting down MySQL.. SUCCESS!Starting MySQL... SUCCESS![root@arslinux-01 ~]# ll /data/mysql/总用量 110748-rw-rw---- 1 mysql mysql 120 6月 1 17:35 arselinux.000001-rw-rw---- 1 mysql mysql 19 6月 1 17:35 arselinux.index-rw-rw---- 1 mysql mysql 128324 6月 1 17:35 arslinux-01.err-rw-rw---- 1 mysql mysql 5 6月 1 17:35 arslinux-01.pid-rw-rw---- 1 mysql mysql 56 5月 13 21:55 auto.cnf-rw-rw---- 1 mysql mysql 12582912 6月 1 17:35 ibdata1-rw-rw---- 1 mysql mysql 50331648 6月 1 17:35 ib_logfile0-rw-rw---- 1 mysql mysql 50331648 5月 13 21:50 ib_logfile1drwx------ 2 mysql mysql 4096 5月 21 22:49 mysqldrwx------ 2 mysql mysql 4096 5月 21 22:43 mysql2drwx------ 2 mysql mysql 4096 5月 13 21:50 performance_schemadrwx------ 2 mysql mysql 6 5月 13 21:50 testdrwx------ 2 mysql mysql 324 5月 28 23:03 zrlog
备份 mysql 库，创建 arslinux 库，将备份导入 arslinux 库
[root@arslinux-01 ~]# mysqldump -uroot -parslinux mysql > /tmp/mysql.sqlWarning: Using a password on the command line interface can be insecure.[root@arslinux-01 ~]# mysql -uroot -parslinux -e'create database arslinux'Warning: Using a password on the command line interface can be insecure.[root@arslinux-01 ~]# mysql -uroot -parslinux arslinux < /tmp/mysql.sqlWarning: Using a password on the command line interface can be insecure.
创建用作主从同步的用户
mysql> grant replication slave on *.* to 'repl'@192.168.194.132 identified by '123456';Query OK, 0 rows affected (0.00 sec)
锁表，防止数据变动
mysql> flush tables with read lock;Query OK, 0 rows affected (0.01 sec)
查看主状态
mysql> show master status;+------------------+----------+--------------+------------------+-------------------+| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |+------------------+----------+--------------+------------------+-------------------+| arselinux.000001 | 655378 | | | |+------------------+----------+--------------+------------------+-------------------+1 row in set (0.00 sec)
备份 /data/mysql 下需要主从同步的数据库
[root@arslinux-01 ~]# mysqldump -uroot -parslinux mysql2 > /tmp/mysql2.sqlWarning: Using a password on the command line interface can be insecure.[root@arslinux-01 ~]# mysqldump -uroot -parslinux zrlog > /tmp/zrlog.sqlWarning: Using a password on the command line interface can be insecure.[root@arslinux-01 ~]# mysqldump -uroot -parslinux arslinux > /tmp/arslinux.sqlWarning: Using a password on the command line interface can be insecure.
17.4 配置从
编辑配置 /etc/my.cnf，增加server-id（从不需要bin_log,只有主才需要）
[root@arslinux-02 mysql]# vim /etc/my.cnfserver-id = 132
重启 mysql
[root@arslinux-02 mysql]# /etc/init.d/mysqld restartShutting down MySQL.. SUCCESS!Starting MySQL.. SUCCESS![root@arslinux-02 mysql]# ll /data/mysql/总用量 110608-rw-rw---- 1 mysql mysql 5 6月 1 18:19 arslinux-02.pid-rw-rw---- 1 mysql mysql 56 6月 1 16:56 auto.cnf-rw-rw---- 1 mysql mysql 12582912 6月 1 18:19 ibdata1-rw-rw---- 1 mysql mysql 50331648 6月 1 18:19 ib_logfile0-rw-rw---- 1 mysql mysql 50331648 6月 1 16:51 ib_logfile1drwx------ 2 mysql mysql 4096 6月 1 16:51 mysqldrwx------ 2 mysql mysql 4096 6月 1 16:51 performance_schemadrwx------ 2 mysql mysql 6 6月 1 16:48 test
传输数据，将主上库备份传到从上
[root@arslinux-02 mysql]# scp 192.168.194.130:/tmp/*.sql /tmp/arslinux.sql 100% 638KB 14.6MB/s 00:00mysql2.sql 100% 632KB 14.2MB/s 00:00mysql.sql 100% 638KB 13.6MB/s 00:00zrlog.sql 100% 10KB 2.2MB/s 00:00
给 mysql 和 mysqldump 做 alias（因为没加入 PATH ）
[root@arslinux-02 mysql]# alias 'mysql=/usr/local/mysql/bin/mysql'[root@arslinux-02 mysql]# alias 'mysqldump=/usr/local/mysql/bin/mysqldump'
创建库
[root@arslinux-02 mysql]# mysql -urootWelcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 1Server version: 5.6.43 MySQL Community Server (GPL)Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql> create database arslinux;Query OK, 1 row affected (0.00 sec)mysql> create database mysql2;Query OK, 1 row affected (0.00 sec)mysql> create database zrlog;Query OK, 1 row affected (0.00 sec)mysql> quit;Bye
恢复数据到数据库
[root@arslinux-02 mysql]# mysql -uroot arslinux < /tmp/arslinux.sql[root@arslinux-02 mysql]# mysql -uroot mysql2 < /tmp/mysql2.sql[root@arslinux-02 mysql]# mysql -uroot zrlog < /tmp/zrlog.sql[root@arslinux-02 mysql]# ll /data/mysql/总用量 226264drwx------ 2 mysql mysql 4096 6月 1 18:28 arslinux-rw-rw---- 1 mysql mysql 5 6月 1 18:19 arslinux-02.pid-rw-rw---- 1 mysql mysql 56 6月 1 16:56 auto.cnf-rw-rw---- 1 mysql mysql 79691776 6月 1 18:29 ibdata1-rw-rw---- 1 mysql mysql 50331648 6月 1 18:29 ib_logfile0-rw-rw---- 1 mysql mysql 50331648 6月 1 16:51 ib_logfile1drwx------ 2 mysql mysql 4096 6月 1 16:51 mysqldrwx------ 2 mysql mysql 4096 6月 1 18:28 mysql2drwx------ 2 mysql mysql 4096 6月 1 16:51 performance_schemadrwx------ 2 mysql mysql 6 6月 1 16:48 testdrwx------ 2 mysql mysql 324 6月 1 18:29 zrlog
实现主从同步
[root@arslinux-02 mysql]# mysql -urootWelcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 6Server version: 5.6.43 MySQL Community Server (GPL)Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql> stop slave;Query OK, 0 rows affected, 1 warning (0.00 sec)mysql> change master to master_host='192.168.194.130',master_user='repl',master_password='123456',master_log_file='arselinux.000001',master_log_pos=655378;Query OK, 0 rows affected, 2 warnings (0.04 sec)mysql> start slave;Query OK, 0 rows affected (0.01 sec)mysql> show slave status\G*************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 192.168.194.130Master_User: replMaster_Port: 3306Connect_Retry: 60Master_Log_File: arselinux.000001Read_Master_Log_Pos: 655378Relay_Log_File: arslinux-02-relay-bin.000002Relay_Log_Pos: 283Relay_Master_Log_File: arselinux.000001Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno: 0Last_Error:Skip_Counter: 0Exec_Master_Log_Pos: 655378Relay_Log_Space: 462Until_Condition: NoneUntil_Log_File:Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_SSL_CA_File:Master_SSL_CA_Path:Master_SSL_Cert:Master_SSL_Cipher:Master_SSL_Key:Seconds_Behind_Master: 0Master_SSL_Verify_Server_Cert: NoLast_IO_Errno: 0Last_IO_Error:Last_SQL_Errno: 0Last_SQL_Error:Replicate_Ignore_Server_Ids:Master_Server_Id: 130Master_UUID: c164593f-7586-11e9-a13a-000c2924eaf2Master_Info_File: /data/mysql/master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update itMaster_Retry_Count: 86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp:Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position: 01 row in set (0.00 sec)
status中 Slave_IO_Running 和 Slave_SQL_Running 如果两个都是 Yes 表示配置主从成功
还需关注
Seconds_Behind_Master: 0 //为主从延迟的时间
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
到主上将表恢复写操作
[root@arslinux-01 ~]# mysql -uroot -parslinuxWarning: 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 15Server version: 5.6.43-log MySQL Community Server (GPL)Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql> unlock tables;Query OK, 0 rows affected (0.00 sec)
错误汇总：
1，Slave_IO_Running: No
查看错误问题：
Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server UUIDs; these UUIDs must be different for replication to work.
查看主从服务器两台机器/data/mysql/auto.cnf的UUID是否一样，如果一样，删除其中一个，并重启该服务器，再次进行从服务器mysql的change master操作就能成功了。
17.5 测试主从同步
在my.cnf中定义：可以在主上，也可以在从上
主服务器上
binlog-do-db= //仅同步指定的库
binlog-ignore-db= //忽略指定库
从服务器上
replicate_do_db=
replicate_ignore_db=
replicate_do_table=
replicate_ignore_table=
replicate_wild_do_table= //如arslinux.%, 支持通配符%
replicate_wild_ignore_table=
最常用是最后两条
验证是否同步
主：
mysql> select count(*) user;+------+| user |+------+| 1 |+------+1 row in set (0.00 sec)
从：
mysql> select count(*) user;+------+| user |+------+| 1 |+------+1 row in set (0.00 sec)
主：
mysql> truncate table user;Query OK, 0 rows affected (0.00 sec)mysql> select * from user;Empty set (0.00 sec)
从：
mysql> select * from user;Empty set (0.01 sec)
主上直接删除表
主：
mysql> drop table user;Query OK, 0 rows affected (0.00 sec)
从：
mysql> select * from user;ERROR 1146 (42S02): Table 'arslinux.user' doesn't exist
如果主从出现错误，可以尝试从上 stop slave，再 start slave，如果还是有问题，那么就要重新做主从了
测试主从：
主上 mysql -uroot arslinux
select count(*) from db;
truncate table db;
到从上 mysql -uroot arslinux
select count(*) from db;
主上继续drop table db;
从上查看db表
有人遇到主从不能正常同步，提示uuid相同的错误。这是因为克隆机器导致。
https://www.2cto.com/database/201412/364479.html
扩展部分
不停库不锁表在线主从配置
主从不同步
主主
关于 auto_increment
mysql-proxy 实现读写分离
mysql-proxy类似的产品有：
mycat 基于阿里的开源软件cobar，官网
mycat实现分库分表
atlas 出自于360，不维护不更新了
mysql环形主从
mysql架构演变
MHA架构
比较复杂的mysql集群架构
直播笔记
1.xtrabackup ——> innobackupex(支持myisam) 不锁表备份
mariadb 备份和恢复
2.几篇和mysql主从有关的文章 关键词 GTID
3.了解几个关键词
读写分离 一主一从，一主多从，一主写，从只读，降低负载
分库分表