​ 我们现在模拟的是主从(1台主机、一台从机)，其主从同步的原理，就是对

bin-log

二进制文件的同步，将这个文件的内容从主机同步到从机。

一、配置文件的修改

1、主机配置文件修改配置

​ 我们首先需要mysql主机(

192.168.254.130

)的

/etc/my.cnf

配置文件，添加如下配置:

#主机唯一ID
server-id=1
#二进制日志
log-bin=mysql-bin
#不需要同步的数据库
binlog-ignore-db=mysql
binlog-ignore-db=information_schema
#同步的数据库名称
binlog-do-db=mycat
#二进制的格式
binlog_format=STATEMENT

​ 我们看下目前整个

my.cnf

文件

[root@localhost Desktop]# cat /etc/my.cnf
[mysqld]
datadir=/usr/local/mysql/data
basedir=/usr/local/mysql
socket=/usr/local/mysql/data/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

server-id=1
log-bin=mysql-bin
binlog-ignore-db=mysql
binlog-ignore-db=information_schema
binlog-do-db=mycat
binlog_format=STATEMENT


[mysqld_safe]
log-error=/usr/local/mysql/data/mysqld.log
pid-file=/usr/local/mysql/data/mysqld/mysqld.pid
[root@localhost Desktop]# 

​ 修改主机的配置文件后，我们需要通过命令重启下服务:

[root@localhost support-files]# ls
magic  mysqld_multi.server  mysql-log-rotate  mysql.server
[root@localhost support-files]# pwd
/usr/local/mysql/support-files
[root@localhost support-files]# ./mysql.server restart

​ 然后我们修改下从机(

192.168.254.131

)的配置文件。

2、从机的配置

​ 从机的配置修改比较简单：

#从机机器唯一ID
server-id=2
#中继日志
relay-log=mysql-relay

​ 同样修改配置后，我们重启下从机

二、mysql客户端命令操作

​ 下面我们可以通过命令连接到mysql的命令端：

[root@localhost bin]# 
[root@localhost bin]# pwd
/usr/local/mysql/bin
[root@localhost bin]# ./mysql -uroot -p

1、主机操作

1）、创建同步用户

​ 首先我们可以在主机创建一个专门用于主从同步用户，通过命令：

​

GRANT REPLICATION SLAVE ON *.* TO 'SLAVE'@'%' IDENTIFIED BY '123456';


2）、查看同步文件状态

​ 然后我们通过

show master status;

查看主机的同步内容状态：

mysql> show master status;
+------------------+----------+--------------+--------------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB         | Executed_Gtid_Set |
+------------------+----------+--------------+--------------------------+-------------------+
| mysql-bin.000001 |      154 | mycat        | mysql,information_schema |                   |
+------------------+----------+--------------+--------------------------+-------------------+
1 row in set (0.00 sec)

2、从机操作

1）、设置从机的主机

执行如下命令，这里设置了我们与主机建立同步的相关信息

CHANGE MASTER TO MASTER_HOST='192.168.254.130',
MASTER_USER='SLAVE',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000001',
MASTER_LOG_POS=430;

​ 这里如果提示已经设置了主机配置，可以通过

stop slave

&

reset master

进行重置。

2）、启动同步

​ 下面我们再通过

start slave

开启同步：

​ 就可以看到：

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.254.130
                  Master_User: SLAVE
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 592
               Relay_Log_File: mysql-relay.000002
                Relay_Log_Pos: 482
        Relay_Master_Log_File: mysql-bin.000001
             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: 592
              Relay_Log_Space: 685
              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
                  Master_UUID: 74397a99-accf-11eb-ae0d-000c2912d302
             Master_Info_File: /usr/local/mysql/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

mysql> 

​ 这里我们可以看到

Slave_IO_Running

、

Slave_SQL_Running

都为

YES

，则成功了，如果是下面这种：

*************************** 1. row ***************************
               Slave_IO_State: Connecting to master
                  Master_Host: 192.168.254.130
                  Master_User: slave
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 430
               Relay_Log_File: mysql-relay.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Connecting
            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: 430
              Relay_Log_Space: 154
              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: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 1045
                Last_IO_Error: error connecting to master 'slave@192.168.254.130:3306' - retry-time: 60  retries: 1
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 0
                  Master_UUID: 
             Master_Info_File: /usr/local/mysql/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 210505 00:18:08
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

​ 我们可以看到

Last_IO_Error

这里有错误，我们就可以去看下日志报的什么问题了，目前我这个是因为同步用户写错了才不能同步，按上面说的先停止同步重置，修改后同步命令，再操作一遍就可以了。

三、主从同步测试

1、主机创建库

​ 我们先在主机创建我们前面设置的要同步的数据库

mycat

：

mysql> create database mycat;
Query OK, 1 row affected (0.00 sec)

mysql> use mycat;
Database changed
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mycat              |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

mysql> 

2、从机查看库

​ 然后我们就能在从机看到这个库了

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mycat              |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

3、表数据的初始

​ 下面我们进行表数据的测试

1）、主机

​ 首先我们再主机建立表并插入数据

mysql> use mycat;
Database changed
mysql> 
mysql> create table `test1`(
    -> id int auto_increment not null primary key,
    -> name varchar(10) default null
    -> );
Query OK, 0 rows affected (0.03 sec)

mysql> insert into test1(`id`,`name`) value(1,"petty");
Query OK, 1 row affected (0.16 sec)

mysql> select * from test1;
+----+-------+
| id | name  |
+----+-------+
|  1 | petty |
+----+-------+
1 row in set (0.00 sec)

mysql> 

2）、从机

下面我们在从机查看看有没有成功同步：

mysql> use mycat;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+-----------------+
| Tables_in_mycat |
+-----------------+
| test1           |
+-----------------+
1 row in set (0.00 sec)

mysql> select * from test1;
+----+-------+
| id | name  |
+----+-------+
|  1 | petty |
+----+-------+
1 row in set (0.00 sec)

mysql> 

​ 可以看到我们的主从配置已经成功了。

四、多主多从

​ 我们还可以多主多从，例如我们一个主从序列是编号1位主机、编号2为从机，然后编号3为主机、编号4为从机，同时编号1主机与编号3主机相互为主从，这样就是其中主机一台有问题，整个mysql集群还是能正常工作。

​ 由于目前只有3台机，只使用三台来写demo(一台windows，两台linux)。

1、编号1主机(192.168.254.30)

1）、修改配置

​ 我们首先需要修改其原来的

etc/my.cnf

文件，添加：

# 作为从机也修改其bin-log日志
log-slave-updates
#自增长的幅度
auto-increment-increment=2
#自增长的开始位置
auto-increment-offset=1

​ 整个文件的信息

[root@localhost Desktop]# cat /etc/my.cnf
[mysqld]
datadir=/usr/local/mysql/data
basedir=/usr/local/mysql
socket=/usr/local/mysql/data/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

server-id=1
log-bin=mysql-bin
binlog-ignore-db=mysql
binlog-ignore-db=information_schema
binlog-do-db=mycat
binlog_format=STATEMENT

log-slave-updates
auto-increment-increment=2
auto-increment-offset=1

[mysqld_safe]
log-error=/usr/local/mysql/data/mysqld.log
pid-file=/usr/local/mysql/data/mysqld/mysqld.pid
[root@localhost Desktop]# 

​ 修改这个文件后我们需要重启机器

2、编号2从机（192.168.254.31）

​ 这台原来已经配置其连接30机器了，所以这次不用修改

3、编号3主机(192.168.254.1)

1）、修改配置文件

​ 由于这台机器是windows，所以我们需要修改其的

my.ini

文件，在其最后面添加

server-id=3
log-bin=mysql-bin
binlog-ignore-db=mysql
binlog-ignore-db=information_schema
binlog-do-db=mycat
binlog_format=STATEMENT

log-slave-updates
auto-increment-increment=2
auto-increment-offset=2

​ 注意我们上面改了

server-id

，同时也改了其的增长开始点

auto-increment-offset=2

。同时再重启服务。

2）、创建同步用户

​ 首先我们可以在主机创建一个专门用于主从同步用户，通过命令：

​

GRANT REPLICATION SLAVE ON *.* TO 'SLAVE'@'%' IDENTIFIED BY '123456';


3）、查看状态

mysql> show master status;
+------------------+----------+--------------+--------------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB         | Executed_Gtid_Set |
+------------------+----------+--------------+--------------------------+-------------------+
| mysql-bin.000001 |      154 | mycat        | mysql,information_schema |                   |
+------------------+----------+--------------+--------------------------+-------------------+
1 row in set (0.00 sec)

mysql>

4）、设置同步的状态

​ 下面我们运行其连接的主机(30)信息

CHANGE MASTER TO MASTER_HOST='192.168.254.130',
MASTER_USER='SLAVE',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000001',
MASTER_LOG_POS=430;

5）、编号1主机同步(192.168.254.30)

​ 我们需要设置其去同步编号3主机(192.168.254.1)，即我们前面查看的编号3的(

master status

)：

CHANGE MASTER TO MASTER_HOST='192.168.254.1',
MASTER_USER='SLAVE',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000001',
MASTER_LOG_POS=154;

​ 然后我们在编号1主机执行同步

start slave;

，也在编号3主机执行同步

start slave;

。

4、测试查看

1）、可能的问题(可略过)

​ 现在我们测试，然后分别查看这两台的master状态

show master status;

。

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.254.1
                  Master_User: SLAVE
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 154
               Relay_Log_File: localhost-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
........

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.254.130
                  Master_User: SLAVE
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000002
          Read_Master_Log_Pos: 462
               Relay_Log_File: LAPTOP-QR83QEC0-relay-bin.000003
                Relay_Log_Pos: 675
        Relay_Master_Log_File: mysql-bin.000002
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB:
.........

​ 可以看到它们的同步都是

yes

。这里可能有问题，我们需要自己解决，例如我在编号1机器修改配置，然后在查看其的状态，

mysql> show master status;
+------------------+----------+--------------+--------------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB         | Executed_Gtid_Set |
+------------------+----------+--------------+--------------------------+-------------------+
| mysql-bin.000002 |      462 | mycat        | mysql,information_schema |                   |
+------------------+----------+--------------+--------------------------+-------------------+
1 row in set (0.00 sec)

mysql> 

​ 我如果以这个消息去让编号3机器同步编号1，就会报(因为我又运行了一条新的插入语句)，但建表语句是在日志

mysql-bin.000001

，而这里我因为重启了，其有有新的

mysql-bin.000002

，所以有修改回了原来编号2的同步信息。

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.254.130
                  Master_User: SLAVE
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000002
          Read_Master_Log_Pos: 462
               Relay_Log_File: LAPTOP-QR83QEC0-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000002
             Slave_IO_Running: Yes
            Slave_SQL_Running: No
              Replicate_Do_DB:
          Replicate_Ignore_DB:
           Replicate_Do_Table:
       Replicate_Ignore_Table:
      Replicate_Wild_Do_Table:
  Replicate_Wild_Ignore_Table:
                   Last_Errno: 1146
                   Last_Error: Error 'Table 'mycat.test1' doesn't exist' on query. Default database: 'mycat'. Query: 'insert into test1(`id`,`name`) value(2,"TOm")'

2）、在编号3插入数据

​ 下面我们再编号3插入数据，看编号1、2能不能看到

​ 在编号3操作：

mysql> insert into test1(`id`,`name`) value(3,"kitt");
Query OK, 1 row affected (0.01 sec)

mysql> select * from test1;
+----+-------+
| id | name  |
+----+-------+
|  1 | petty |
|  2 | TOm   |
|  3 | kitt  |
+----+-------+
3 rows in set (0.00 sec)

mysql>

​ 在编号1查看

mysql> select * from test1;
+----+-------+
| id | name  |
+----+-------+
|  1 | petty |
|  2 | TOm   |
|  3 | kitt  |
+----+-------+
3 rows in set (0.00 sec)

mysql> 

​ 在编号2查看

mysql> select * from test1;
+----+-------+
| id | name  |
+----+-------+
|  1 | petty |
|  2 | TOm   |
|  3 | kitt  |
+----+-------+
3 rows in set (0.00 sec)

mysql> 

​ 可以看到目前我们已经同步成功了，在编号1中能查看到主机编号3的插入信息。

3）、编号1处理数据

​ 下面我们在编号1操作查看

编号1：

mysql> insert into test1(`id`,`name`) value(4,"lisa");
Query OK, 1 row affected (0.00 sec)

mysql> select * from test1;
+----+-------+
| id | name  |
+----+-------+
|  1 | petty |
|  2 | TOm   |
|  3 | kitt  |
|  4 | lisa  |
+----+-------+
4 rows in set (0.00 sec)

mysql> 

编号3：

mysql> select * from test1;
+----+-------+
| id | name  |
+----+-------+
|  1 | petty |
|  2 | TOm   |
|  3 | kitt  |
|  4 | lisa  |
+----+-------+
4 rows in set (0.00 sec)

mysql>

​ 可以看到其是相互同步的。