MySQL-主从复制

MySQL-主从-主主配置

标签（空格分隔）： mysql

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环境准备

两台linux虚拟机：
A: 192.168.135.140 [主服务器]
B: 192.168.135.141 [从服务器]

主从复制

步骤-思路：

1 修改两台msyq配置文件 [vi /etc/my.cnf]

2 在主服务器[A]创建用户：
grant replication slave on . to '自定义用户名'@'从服务器IP[B]' identified by '自定义用户密码';

3 刷新权限
flush privileges;

4 查看主服务器[A]二进制日志名和位置
show master status;

5 在从服务器[B]告知二进制文件名与位置
slave stop; 关闭复制

change master to master_host='主服务器IP[A]', master_user='在服务器创建的用户', master_password='密码', master_log_file='主服务器的日志名', master_log_pos=主服务器的位置;

6 查看slave
slave start;
show slave status\G;

修改配置

依次修改A B 两台服务器MySQL配置文件
vi /etc/my.cnf
A :
log-bin=mysql-bin
binlog_format=mixed
server-id = 1
expire_logs_days = 10

B :
log-bin=mysql-bin
binlog_format=mixed
server-id = 2
expire_logs_days = 10

注意：二进制日志必须开启，因为数据的同步实质上就是其他的MySQL数据库服务器将这个数据变更的二进制日志在本机上再执行一遍。

开始主从复制

在A服务器中创建一个B服务器可以登陆的mysql用户
username: user2
password: user2

在A服务器：
mysql> grant replication slave on . to 'user2'@'192.168.135.141' identified by 'user2';
Query OK, 0 rows affected (0.01 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000019 | 338 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)

在B服务：
mysql> slave stop;

mysql> change master to master_host='192.168.135.140', master_user='user2', master_password='user2', master_log_file='mysql-bin.000019', master_log_pos=338;
Query OK, 0 rows affected (0.04 sec)

mysql> slave start;

测试

mysql> slave start;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.135.140
Master_User: user2
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000009
Read_Master_Log_Pos: 796
Relay_Log_File: cherry-relay-bin.000002
Relay_Log_Pos: 253
Relay_Master_Log_File: mysql-bin.000009
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB: yanweifeng
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: 796
Relay_Log_Space: 410
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: 1
1 row in set (0.00 sec)

当 Slave_IO_Running: Yes | Slave_SQL_Running: Yes 都是Yes时才配置成功

主主配置

思路和主从配置一样，就是把上边的操作反过来再执行一遍就可以。接着上面继续执行

在从服务器[B]创建用户，刷新权限，查看二进制文件名和位置，
关闭复制，在主服务器[A]告知二进制文件名与位置，开启复制，查看slave服务

从服务器：

mysql> grant replication slave on . to 'user1'@'192.168.135.140' identified by '123456';
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> show master status\G;
*************************** 1. row ***************************
File: mysql-bin.000016
Position: 432
Binlog_Do_DB:
Binlog_Ignore_DB:
1 row in set (0.00 sec)

ERROR:
No query specified

mysql>

----------------------------------------------------------------------------------------------
主服务器：

mysql> slave stop;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> change master to master_host='192.168.135.141', master_user='user2', master_password='123456', master_log_file='mysql-bin.000016', master_log_pos=432;
Query OK, 0 rows affected (0.02 sec)

mysql>
mysql> slave start;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.135.141
Master_User: user2
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000016
Read_Master_Log_Pos: 432
Relay_Log_File: cherry-relay-bin.000002
Relay_Log_Pos: 253
Relay_Master_Log_File: mysql-bin.000016
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: 432
Relay_Log_Space: 410
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: 2
1 row in set (0.00 sec)

ERROR:
No query specified

mysql>

测试

分别在两台服务器操作 看是否同步

常见出错点：

1 两台数据库都存在db数据库，而第一台MySQL db中有tab1，第二台MySQL db中没有tab1，那肯定不能成功。
2 已经获取了数据的二进制日志名和位置，又进行了数据操作，导致POS发生变更。在配置CHANGE MASTER时还是用到之前的POS。
3 stop slave后，数据变更，再start slave。出错。