Mysql主从复制原理
1.Mysql主从复制目的是为了备份主库数据，方便及时恢复数据，分担主库压力。
2.Mysql主从复制属于异步复制过程，整个过程需要开启三个线程：Master侧开启I/O线程，Slave侧开启I/O、SQL线程。
3.Master侧开启bin-log二进制日志功能，bin-log日志主要用来记录增、删、改、更新操作的SQL语句。
4.Slave侧通过I/O线程来读取Master的bin-log文件内容，并把内容存储在本地的中继日志relay-log中，同时会写入master.info文件（该文件记录master IP、端口、同步的用户名、密码、bin-log文件名以及最新的position位置点），供下次数据同步使用。
5.Slave侧SQL线程检测到中继日志内容有更新，解析更新的SQL语句，并在本地数据库执行，保持Slave和Master数据同步的。
主从复制安装配置
1.系统环境准备
Master：192.168.241.133
Slave：192.168.241.135
2.安装
| 源码安装参考： http://blog.csdn.net/scott_bing/article/details/78261789 Yum安装： yum install mysql-server mysql-devel mysql-libs -y CentOS6.x YUM安装 yum install mariadb-server mariadb mariadb-libs -y CentOS7.x YUM安装 |
3.Master侧配置
在/etc/my.cnf中[mysqld]下添加以下代码，配置完后重启mysql服务
| server-id = 1 log-bin = mysql-bin |
|
[client] port = 3306 socket = /tmp/mysql.sock [mysqld] port = 3306 socket = /tmp/mysql.sock skip-external-locking key_buffer_size =256M max_allowed_packet= 1M table_open_cache= 256 sort_buffer_size= 1M read_buffer_size= 1M read_rnd_buffer_size= 4M myisam_sort_buffer_size= 64M thread_cache_size= 8 query_cache_size=16M thread_concurrency= 8 log-bin=mysql-bin binlog_format=mixed server-id = 1 [mysqldump] quick max_allowed_packet= 16M [mysql] no-auto-rehash [myisamchk] key_buffer_size =128M sort_buffer_size= 128M read_buffer = 2M write_buffer = 2M [mysqlhotcopy] interactive-timeout |
创建供Slave库进行同步的用户、密码，执行如下命令，最后查看主库的状态
|
grant replication slave on *.* to 'tongbu'@'%' identified by '123456'； flush privilege; 执行show master status 查看主库的状态 |
在/etc/my.cnf中[mysqld]段添加以下代码：
| server-id = 2 该值配置与master不一致即可 |
/etc/my.cnf完整配置：
|
[client] port = 3306 socket = /tmp/mysql.sock [mysqld] server-id = 2 port = 3306 socket = /tmp/mysql.sock skip-external-locking key_buffer_size =256M max_allowed_packet= 1M table_open_cache= 256 sort_buffer_size= 1M read_buffer_size= 1M read_rnd_buffer_size= 4M myisam_sort_buffer_size= 64M thread_cache_size= 8 query_cache_size=16M thread_concurrency= 8 [mysqldump] quick max_allowed_packet= 16M [mysql] no-auto-rehash [myisamchk] key_buffer_size =128M sort_buffer_size= 128M read_buffer = 2M write_buffer = 2M [mysqlhotcopy] interactive-timeout |
Slave指定Master IP、用户名、密码、bin-log文件名（mysql-bin.000010）及position（120），代码如下：
| change master to master_host='192.168.241.133',master_user='tongbu',master_password='123456',master_log_file='mysql-bin.000010',master_log_pos=120; |
| start slave; show slave status； Slave_IO_Running: Yes Slave_SQL_Running: Yes |
Master侧创建db_test数据库和tb_01表，命令如下：
| create database db_test charset=utf8; show databases; use db_test; create table tb_01(id varchar(20),name varchar(20)); show tables; |
Slave侧查看是否有数据库db_test和表tb_01，若有则表示Slave从Master复制数据成功
