17.1 MySQL主从介绍
1. 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
2. MySQL主从是基于binlog的，主上须开启binlog才能进行主从。
3. 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
4. 主上有一个log dump线程，用来和从的I/O线程传递binlog
5. 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
MySQL主从原理图 ：
1.在两个centos系统上安装mysql，安装方法见 ：
11.3 MySQL安装（上）；11.4 MySQL安装（中）；11.5 MySQL安装下
2.查看第一台和第二台服务器mysql是否启动。
[root@aminglinux-128 ~]# ps aux |grep mysql root 1088 0.0 0.0 115432 288 ? S 9月01 0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/aminglinux-128.pid mysql 1303 0.0 31.8 1313108 317424 ? Sl 9月01 1:22 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=aminglinux-128.err --pid-file=/data/mysql/aminglinux-128.pid --socket=/tmp/mysql.sock --port=3306 root 24929 0.0 0.0 112720 984 pts/2 R+ 16:26 0:00 grep --color=auto mysql
[root@localhost ~]# ps aux |grep mysql root 12891 0.0 0.1 11812 1612 pts/0 S 16:28 0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/mysqld.pid mysql 13071 60.5 17.5 1119428 175124 pts/0 Sl 16:28 0:10 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=localhost.localdomain.err --pid-file=/data/mysql/mysqld.pid --socket=/tmp/mysql.sock --port=3306 root 13129 0.0 0.0 112720 980 pts/0 S+ 16:28 0:00 grep --color=auto mysql
3.在第一台服务器上进行设置。
[root@aminglinux-128 ~]# vim /etc/my.cnf
2. 重启mysql ：
[root@aminglinux-128 ~]# /etc/init.d/mysqld restart Shutting down MySQL....................... SUCCESS! Starting MySQL................. SUCCESS!
3. 查看/data/mysql/目录下,生成以(log_bin)haozc开头的文件 ：
[root@aminglinux-128 ~]# ls /data/mysql/aminglinux.* /data/mysql/aminglinux.000001 /data/mysql/aminglinux.index
4. 进入 /data/mysql/目录 ：
[root@aminglinux-128 ~]# cd /data/mysql/ [root@aminglinux-128 mysql]# [root@aminglinux-128 mysql]#
5. 创建一个新的库，库名为aminglinux ：
[root@aminglinux-128 mysql]# mysql -uroot -phaomima -e "create database aminglinux" Warning: Using a password on the command line interface can be insecure.
把ceshiku库备份并恢复成aminglinux库，作为测试数据
6. 备份mysql数据库，做测试 ：
[root@aminglinux-128 mysql]# mysqldump -uroot -phaomima ceshiku > /tmp/ceshiku.sql Warning: Using a password on the command line interface can be insecure.
7. 把备份的ceshiku.sql库文件，恢复到aminglinux库 ：
[root@aminglinux-128 mysql]# mysql -uroot -phaomima aminglinux < /tmp/ceshiku.sql
8. hao1机器主 所有mysql数据库备份到/tmp/下 ：
[root@aminglinux-128 mysql]# ls aminglinux aminglinux-128.err aminglinux.index ceshiku ibdata1 ib_logfile1 mysql2 test aminglinux.000001 aminglinux-128.pid auto.cnf db1 ib_logfile0 mysql performance_schema
[root@aminglinux-128 mysql]# mysqldump -uroot -phaomima aminglinux > /tmp/haozc.sql Warning: Using a password on the command line interface can be insecure. [root@aminglinux-128 mysql]# mysqldump -uroot -phaomima mysql2 > /tmp/mysql2.sql Warning: Using a password on the command line interface can be insecure. [root@aminglinux-128 mysql]# mysqldump -uroot -phaomima db1 > /tmp/db1.sql Warning: Using a password on the command line interface can be insecure. [root@aminglinux-128 mysql]# mysqldump -uroot -phaomima ceshiku > /tmp/ceshiku.sql Warning: Using a password on the command line interface can be insecure.
9. 进入mysql(root用户下）：
[root@aminglinux-128 mysql]# mysql -uroot -phaomima Warning: Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g.
10. 创建repl用户，针对ip是aminglinux2从ip ：
mysql> grant replication slave on *.* to 'repl'@'192.168.193.129' identified by 'haomima'; Query OK, 0 rows affected (0.36 sec)
11. 表状态锁上，暂时不能再写入数据 ：
mysql> flush tables with read lock; Query OK, 0 rows affected (0.00 sec)
12. 查看红框中两个数值，hao2机器从上需要用这两个数值 ：
mysql> show master status; +-------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-------------------+----------+--------------+------------------+-------------------+ | aminglinux.000001 | 444 | | | | +-------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)
17.4 配置从
1. 编辑/etc/my.cnf配置文件 ：
添加server-id=129
[root@localhost ~]# vim /etc/my.cnf [client] port = 3306 socket = /tmp/mysql.sock [mysqld] port = 3306 socket = /tmp/mysql.sock server-id=129 basedir = /usr/local/mysql datadir = /data/mysql pid-file = /data/mysql/mysqld.pid server-id = 306 character-set-server = utf8
2. 重启mysql ：
[root@localhost ~]# /etc/init.d/mysqld restart Shutting down MySQL.. SUCCESS! Starting MySQL.. SUCCESS!
3. 用scp命令复制aminglinux-128主/tmp/下所有以.sql备份的mysql数据库文件，粘贴到本机amingliux-129从的/tmp/目录下 ：
[root@localhost ~]# scp 192.168.193.128:/tmp/*.sql /tmp/ The authenticity of host '192.168.193.128 (192.168.193.128)' can't be established. ECDSA key fingerprint is SHA256:/pKbINKTISanvNQ+5fJAqgFOnBJ7wbI68LKeFPZcVA0. ECDSA key fingerprint is MD5:06:1f:8f:91:36:47:28:0c:72:08:6b:9f:28:b0:49:19. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '192.168.193.128' (ECDSA) to the list of known hosts. [email protected]'s password: ceshiku.sql 100% 1807 879.9KB/s 00:00 db1.sql 100% 1258 890.6KB/s 00:00 haozc.sql 100% 1265 856.6KB/s 00:00 mysql2.sql 100% 1261 773.6KB/s 00:00 mysql.sql 100% 646KB 10.0MB/s 00:00 user.sql
4. 如果执行找不到mysql -uroot命令，执行下面命令 ：
[root@aminglinux-129 ~]# alias 'mysql=/usr/local/mysql/bin/mysql'
[root@aminglinux-129 ~]# alias 'mysqldump=/usr/local/mysql/bin/mysqldump'
[root@aminglinux-129~]# ln -s /usr/local/mysql/bin/mysql /usr/bin
5. 登录mysql(登录root用户) ：
mysql -uroot -phaomima
6. hao2从上创建和hao1主一样的mysql用户haozc ：
mysql> create database haozc; Query OK, 1 row affected (0.00 sec) mysql> create database mysql2; ERROR 1007 (HY000): Can't create database 'mysql2'; database exists mysql> create database mysql2; ERROR 1007 (HY000): Can't create database 'mysql2'; database exists mysql> create database ceshiku; ERROR 1007 (HY000): Can't create database 'ceshiku'; database exists mysql> create database zrlog; Query OK, 1 row affected (0.00 sec)
7. 把aminglinux-128机器从 同步的.sql 库文件,恢复到创建对应名称库下 ：
mysql> mysql -uroot zrlog < /tmp/zrlog.sql
不往下运行
8. 登录mysql，执行下面命令 ：
mysql> change master to master_host='192.168.193.128',master_user='repl', master_password='haomima', master_log_file='aminglinux.000001'', master_log_pos=444; Query OK, 0 rows affected, 2 warnings (0.03 sec)
mysql> stop slave -> start slave
mysql> show slave status\G
10. 在aminglinux-128机器主上，把之前锁定的表解锁(恢复写入的操作) ：
[root@aminglinux-128 ~]# mysql -uroot -phaomima 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 6 Server version: 5.6.39-log MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. 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. mysql> unlock tables; Query OK, 0 rows affected (0.00 sec)
17.5 测试主从同步
配置参数
1. 主服务器上 ：
binlog-do-db= //仅同步指定的库(其他库不同步)
binlog-ignore-db= //忽略指定库(其他库都同步)
2. 从服务器上 ：
replicate_do_db= //(不常用)
replicate_ignore_db= //(不常用)
replicate_do_table= //(不常用)
replicate_ignore_table= //(不常用)
replicate_wild_do_table= //如aming.%, (支持通配符%)
replicate_wild_ignore_table=
测试主从：
1. aminglinux-128机器主上操作 ：mysql -uroot -phaomima
切换数据库 ：
mysql> use aminglinux Database changed