MySQL主从复制——实战过程讲解（超细节）

目录

一、环境准备

二、主库配置

1.开启binlog参数并设置server_id的值（随便设置，区分作用）

保存退出，并且重启数据库

2.建立同步账号

3.锁表设置只读

4.查看主库状态

5.备份数据库数据

6.解锁

7.主库备份数据上传到从库

三、从库上设置

1.关闭binlog参数并设置server-id

2.还原从主库备份数据

3.设定从主库同步

 4.修改server-uuid

5.启动从库同步开关

四、测试

创建测试

在master主库上

在从库slave上

删除测试

主库上删除

从库上检验 

---

一、环境准备

准备两台主机，其中一台为主（master），一台为从（slave），并且都装有MySQL数据库

示例：

主库 MySQL master：ip 为192.168.198.140/24，port端口为3306

从库 MySQL slave：ip为192.168.168.141/24，port端口为3306

二、主库配置

1.开启binlog参数并设置server_id的值（随便设置，区分作用）

vim /etc/my.cnf

保存退出，并且重启数据库

2.建立同步账号

mysql> grant replication slave on *.* to 'rep'@'192.168.198.%' identified by '#BenJM123';
Query OK, 0 rows affected, 1 warning (0.02 sec)

mysql> show grants for 'rep'@'192.168.198.%';
+---------------------------------------------------------+
| Grants for [email protected].%                            |
+---------------------------------------------------------+
| GRANT REPLICATION SLAVE ON *.* TO 'rep'@'192.168.198.%' |
+---------------------------------------------------------+
1 row in set (0.00 sec)

3.锁表设置只读

--为后后面备份做准备，注意：生产环境要提前申请停机时间
mysql> flush tables with read lock;
Query OK, 0 rows affected (0.00 sec)

--提示：如果超过设置时间不操作会自动解锁
mysql> show variables like '%timeout%';
+-----------------------------+----------+
| Variable_name               | Value    |
+-----------------------------+----------+
| connect_timeout             | 10       |
| delayed_insert_timeout      | 300      |
| have_statement_timeout      | YES      |
| innodb_flush_log_at_timeout | 1        |
| innodb_lock_wait_timeout    | 50       |
| innodb_rollback_on_timeout  | OFF      |
| interactive_timeout         | 28800    |
| lock_wait_timeout           | 31536000 |
| net_read_timeout            | 30       |
| net_write_timeout           | 60       |
| rpl_stop_slave_timeout      | 31536000 |
| slave_net_timeout           | 60       |
| wait_timeout                | 28800    |
+-----------------------------+----------+
13 rows in set (0.00 sec)

4.查看主库状态

即当前日志文件名和二进制日志偏移量

mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000006 |     1074 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

5.备份数据库数据

-- 示例：我这里用school数据库做演示
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| school             |
| sys                |
+--------------------+
6 rows in set (0.00 sec)

mysql> use school;
Database changed

mysql> show tables;
+------------------+
| Tables_in_school |
+------------------+
| score            |
| student          |
+------------------+
2 rows in set (0.00 sec)

使用mysqldump工具对school数据库进行备份

#创建一个/backup文件用来存放备份数据
[root@master ~]# mkdir /backup

#备份
[root@master ~]# mysqldump -uroot -p'#BenJM123' -B school > /backup/mysql_bak.$(date +%F).sql.gz
mysqldump: [Warning] Using a password on the command line interface can be insecure.

#查看
[root@master ~]# ll /backup/
total 4
-rw-r--r-- 1 root root 3447 Jul 21 13:28 mysql_bak.2023-07-21.sql.gz

6.解锁

mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)

7.主库备份数据上传到从库

[root@master ~]# scp /backup/mysql_bak.2023-07-21.sql.gz 192.168.198.141:/backup/
[email protected]'s password: 
scp: /backup/: Is a directory

发现失败，是因为从库slave没有创建/backup目录，需要去创建

[root@slave ~]# mkdir /backup

现在就可以了，正确输入密码即可

[root@master ~]# scp /backup/mysql_bak.2023-07-21.sql.gz 192.168.198.141:/backup/
[email protected]'s password: 
mysql_bak.2023-07-21.sql.gz                                    100% 3447     2.1MB/s   00:00    

查看，成功上传到从库

#从库
[root@slave ~]# ll /backup/
total 4
-rw-r--r-- 1 root root 3447 Jul 21 13:38 mysql_bak.2023-07-21.sql.gz

三、从库上设置

1.关闭binlog参数并设置server-id

其中，没有binlog参数则无需添加，server-id不能和master主库一样，

vim /etc/my.cnf

重启数据库

2.还原从主库备份数据

检查从库数据库

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

还原操作

[root@slave ~]# cd /backup/
[root@slave backup]# ll
total 4
-rw-r--r-- 1 root root 3447 Jul 21 13:38 mysql_bak.2023-07-21.sql.gz
[root@slave backup]# mysql -uroot -p'#BenJM123' < mysql_bak.2023-07-21.sql.gz 
mysql: [Warning] Using a password on the command line interface can be insecure.

检查还原的数据库，成功还原school库

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

3.设定从主库同步

首先，再次去master主机上查看主库状态

mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000006 |     1074 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

由主库状态表知，从库上的MASTER_LOG_FILE参数的值就是mysql-bin.000006，MASTER_LOG_POS参数的值为1047

mysql> change master to
    -> MASTER_HOST='192.168.198.140',
    -> MASTER_PORT=3306,
    -> MASTER_USER='rep',
    -> MASTER_PASSWORD='#BenJM123',
    -> MASTER_LOG_FILE='mysql-bin.000006',
    -> MASTER_LOG_POS=1074;

 4.修改server-uuid

如果从库是从主库克隆而来的（不是克隆的可忽略此步），所以server-uuid也和主库一样，所以需要修改，改为不一样的

vim /var/lib/mysql/auto.cnf

再重启数据库

 

 

5.启动从库同步开关

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

检查状态

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.198.140
                  Master_User: rep
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000006
          Read_Master_Log_Pos: 1074
               Relay_Log_File: slave-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000006
             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: 1074
              Relay_Log_Space: 527
              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
                  Master_UUID: 2379c3c7-26ad-11ee-bdf4-000c29b5d18a
             Master_Info_File: /var/lib/mysql/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)

其中Slave_IO_Running和Slave_SQL_Running两个参数后面必须是双Yes才算成功

如果不是，失败的可能原因是主从库的配置文件server-id一样、server-uuid一样、密码与同步账号的密码不一致

四、测试

创建测试

在master主库上

随便创建一个数据库db1，建立表tb1，随便插入几个数据

mysql> create database db1;
Query OK, 1 row affected (0.00 sec)

mysql> use db1;
Database changed
mysql> create table tb1(
    -> id int(11),
    -> name varchar(20)
    -> );
Query OK, 0 rows affected (0.01 sec)

mysql> insert into tb1 values(001,'zhangsan'),
    -> (002,'lisi'),
    -> (003,'wangwu');
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> select * from tb1;
+------+----------+
| id   | name     |
+------+----------+
|    1 | zhangsan |
|    2 | lisi     |
|    3 | wangwu   |
+------+----------+
3 rows in set (0.00 sec)

在从库slave上

检查是否有db1数据库，并且是否有数据

 

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db1                |
| mysql              |
| performance_schema |
| school             |
| sys                |
+--------------------+
6 rows in set (0.00 sec)

mysql> use db1;
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_db1 |
+---------------+
| tb1           |
+---------------+
1 row in set (0.00 sec)

mysql> select * from tb1;
+------+----------+
| id   | name     |
+------+----------+
|    1 | zhangsan |
|    2 | lisi     |
|    3 | wangwu   |
+------+----------+
3 rows in set (0.00 sec)

最后，我们看到从库上也自动和主库上保存一致了，也有了新建的数据，这样就成功啦

删除测试

执行删除操作也是一样的

主库上删除

从库上检验 

db1数据库确实被删除了

结束！