mysql主从切换机制torch_MySQL Replication设置(Master/Slave)实现主从复制

一、Master配置

1、my.cnf配置

# vim /etc/mysql/mariadb.conf.d/50-server.cnf

[mysqld]

log-bin=mysql-bin //[必须]启用二进制日志

server-id=140 //[必须]服务器唯一ID，默认是1，一般取IP最后一段

2、重启mysql

sudo service mysql restart

3、在主服务器上建立帐户并授权slave

# mysql -u root -p sD9854fals87s34GB98s

mysql> GRANT REPLICATION SLAVE ON *.* to 'mysync'@'%' identified by 'sD9854fals87s34GB98s';

一般不用root帐号，%表示所有客户端都可能连，只要帐号，密码正确，此处可用具体客户端IP代替，如192.168.245.139，加强安全。

4、登录mysql，查询master的状态

mysql> show master status;

+------------------+----------+--------------+------------------+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |

+------------------+----------+--------------+------------------+

| mysql-bin.000014 | 318 | | |

+------------------+----------+--------------+------------------+

1 row in set (0.00 sec)

注：执行完此步骤后不要再操作主服务器MYSQL，防止主服务器状态值变化。

上面的Position需要记住用于下方使用

二、Slave配置

1、my.cnf配置

# vim /etc/mysql/mariadb.conf.d/50-server.cnf

[mysqld]

log-bin=mysql-bin //[必须]启用二进制日志

server-id=139 //[必须]服务器唯一ID，默认是1，一般取IP最后一段

2、重启mysql

sudo service mysql restart

3、配置从服务器Slave：

master_log_pos是上面Position的值

mysql> change master to master_host='192.168.245.140',master_user='mysync',master_password='sD9854fals87s34GB98s',master_log_file='mysql-bin.000014',master_log_pos=318;

# 注意不要断开，"318"无单引号。

mysql>start slave;

# 启动从服务器复制功能

4、检查从服务器复制功能状态：

复制代码

mysql> show slave status\G

*************************** 1. row ***************************

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.245.140

Master_User: root

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: mysql-bin.000003

Read_Master_Log_Pos: 5669

Relay_Log_File: mysqld-relay-bin.000002

Relay_Log_Pos: 5482

Relay_Master_Log_File: mysql-bin.000003

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: 5669

Relay_Log_Space: 5639

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: 140

1 row in set (0.00 sec)

注：Slave_IO及Slave_SQL进程必须正常运行，即YES状态，否则都是错误的状态。

三、主从服务器测试

主服务器Mysql，建立数据库，并在这个库中建表插入一条数据，观看从库是否也增加了相应的数据库、数据表、数据。

四、清除Slave的配置信息

有时候我们的有许多台Slave库,根据业务需要一台甚至几台不在使用需要下线了.这时候就不在需要从Master同步数据了.那么我们如何清理Slave:

reset slave all;

四、常见错误

可以从Last_IO_Error和Last_SQL_Error配置。

1、

service mysql status

如果出现如下错误需要配置skip-name-resolve参数,作用是不再进行反解析(ip不反解成域名)，这样可以加快数据库的反应时间。：

Nov 16 19:26:28 iZ2zedt5e7ronlirnw6vl3Z mysqld[22185]: 181116 19:26:28 [Warning] IP address '180.76.0.0' could not be resolved: Name or service not known

修改配置文件添加如下代码并重启：

[mysqld]

skip-name-resolve

2、在没有停止slave进程的情况下change master

mysql> change master to master_host='IP', master_user='USER', master_password='PASSWD', master_log_file='mysql-bin.000001',master_log_pos=106;

ERROR 1198 (HY000): This operation cannot be performed with a running slave; run STOP SLAVE first

首先需要执行STOP SLAVE停止

3、slave没有启动

执行start slave启动从服务器复制功能:

# show slave status\G

----------

Slave_IO_Running: No

Slave_SQL_Running: No

4、Got fatal error 1236 from master when reading data from binary log

5、Got fatal error 1236 from master when reading data from binary log: 'binlog truncated in the middle of event; consider out of disk space on master; the first event 'mysql-bin.000017' at 1367, the last event read from 'mysql-bin.000017' at 1367, the last byte read from 'mysql-bin.000017' at 1368.'

解决方案：

stop slave;

下方的master_log_file ，master_log_pos是前方让记住的文件位置，一定不能错

MariaDB [test1]> CHANGE MASTER TO MASTER_LOG_FILE='master-bin.000001',MASTER_LOG_POS=329;

Query OK, 0 rows affected (0.072 sec)

6、Got fatal error 1236 from master when reading data from binary log: 'binlog truncated in the middle of event; consider out of disk space on master; the first event 'mysql-bin.000017' at 1367, the last event read from 'mysql-bin.000017' at 1367, the last byte read from 'mysql-bin.000017' at 1368.'

使用如下代码刷新master的配置，然后根据上方更新一下Slave

flush logs;

show master status;