mysql的主从复制与半同步复制（一）

一、mysql的主从复制复制过程需要至少两个mysql服务节点，mysql的主从复制框架一般都为一主多从，从多机房汇总到数据中心的模式，而复制过程只能从主服务器到从

一、mysql的主从复制

复制过程需要至少两个mysql服务节点，mysql的主从复制框架一般都为一主多从，，从多机房汇总到数据中心的模式，而复制过程只能从主服务器到从服务器实现。

复制过程中，主服务器负责读/写操作，而从服务器只负责读操作

二、主从复制的功能

1、实现数据冗余、异地灾备恢复、备份

2、实现数据的读/写分离

3、实现数据库服务的负载均衡

4、实现高可用与故障切换

5、实现MySQL的升级测试

三、主从复制过程中注意的事项

1、不要混合shi用不同的存储引擎

2、主从服务器的server-id 要保持不同

3、尽力避免修改从服务器的数据库

4、尽可能的使用基于行或基于混合模式的复制，避免使用基于语句的复制

5、主服务器要启动二进制日志，而从节点则是开启中继日志，而且要确保从服务器的复制线程时刻开启着

6、注意因为磁盘及内存的大小不足而导致的复制崩溃

四、主从复制的具体实现过程

mysql主从复制拓扑图

1、准备两个安装过mysql服务的节点xz：172.16.200.5,node2：172.16.200.7,修改主机名并同步时间；

[root@xz ~]# hostname master [root@master ~]# crontab -e */1 * * * * /usr/sbin/ntpdate 172.16.0.1 &> /dev/null [root@node2 ~]# hostname slave [root@slave ~]# crontab -e */1 * * * * /usr/sbin/ntpdate 172.16.0.1 &> /dev/null

2、在主节点上创建有复制权限的用户，于从节点上使用授权用户连接测试；

[root@master ~]# mysql Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 3 Server version: 5.5.33-log MySQL Community Server (GPL) 。。。。。 mysql> grant replication slave,replication client on *.* to 'zly'@'172.16.200.7' identified by 'mypass'; Query OK, 0 rows affected (0.35 sec) mysql> flush privileges; Query OK, 0 rows affected (0.09 sec) mysql> show grants for 'zly'@'172.16.200.7'; +-----------------------------------------------------------------------------------------------------------------------------------------------+ | Grants for zly@172.16.200.7 | +-----------------------------------------------------------------------------------------------------------------------------------------------+ | GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'zly'@'172.16.200.7' IDENTIFIED BY PASSWORD '*6C8989366EAF75BB670AD8EA7A7FC1176A95CEF4' | +-----------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.03 sec) ........... [root@slave ~]# mysql -uzly -pmypass -h 172.16.200.5 Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 4 Server version: 5.5.33-log MySQL Community Server (GPL) Copyright (c) 2000, 2013, 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>

3、修改主从两个节点的配置文件，并重新启动mysql服务;

[root@master ~]# vim /etc/my.cnf log-bin=mysql-bin log_bin_index = mysql_bin.index binlog_format=mixed server-id = 5 [root@master ~]# killall mysqld [root@master ~]# ps aux | grep mysqld root 7700 0.0 0.1 103244 832 pts/3 S+ 09:27 0:00 grep mysqld [root@master ~]# service mysqld restart MySQL server PID file could not be found! [FAILED] Starting MySQL... [ OK ] [root@master ~]# service mysqld restart Shutting down MySQL. [ OK ] Starting MySQL.. [ OK ] ............... [root@slave ~]# vim /etc/my.cnf #log-bin=mysql-bin # binary logging format - mixed recommended #binlog_format=mixed skip_slave_start = 1 read_only = 1 relay_log = relay_log relay_log_index = relay_log.index # required unique id between 1 and 2^32 - 1 # defaults to 1 if master-host is not set # but will not function as a master if omitted server-id = 7 [root@slave ~]# killall mysqld [root@slave ~]# ps aux | grep mysqld root 8796 0.0 0.1 103244 832 pts/4 S+ 23:45 0:00 grep mysqld [root@slave ~]# service mysqld restart MySQL server PID file could not be found! [FAILED] Starting MySQL.. [ OK ] [root@slave ~]# service mysqld restart Shutting down MySQL. [ OK ] Starting MySQL.. [ OK ]

4、查看主节点的二进制日志及其事件位置;

mysql> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000011 | 107 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)

5、与从节点上复制主节点上的数据;

[root@slave ~]# mysql mysql> help change master to Name: 'CHANGE MASTER TO' Description: Syntax: CHANGE MASTER TO option [, option] ... option: MASTER_BIND = 'interface_name' | MASTER_HOST = 'host_name' | MASTER_USER = 'user_name' | MASTER_PASSWORD = 'password' | MASTER_PORT = port_num | MASTER_CONNECT_RETRY = interval | MASTER_HEARTBEAT_PERIOD = interval | MASTER_LOG_FILE = 'master_log_name' | MASTER_LOG_POS = master_log_pos | RELAY_LOG_FILE = 'relay_log_name' | RELAY_LOG_POS = relay_log_pos | MASTER_SSL = {0|1} | MASTER_SSL_CA = 'ca_file_name' | MASTER_SSL_CAPATH = 'ca_directory_name' | MASTER_SSL_CERT = 'cert_file_name' | MASTER_SSL_KEY = 'key_file_name' | MASTER_SSL_CIPHER = 'cipher_list' | MASTER_SSL_VERIFY_SERVER_CERT = {0|1} | IGNORE_SERVER_IDS = (server_id_list) server_id_list: [server_id [, server_id] ... ] ........................................ mysql> change master to -> master_host='172.16.200.5',master_user='zly',master_password='mypass ',master_port=3306,master_log_file='mysql-bin.000011',master_log_pos=107; Query OK, 0 rows affected (0.07 sec)

6、启动从服务器复制线程、查看状态，并查看启动的线程;