mysql5.7主从复制半同步.....

一：mysql5.7主从复制（主从复制为‘异步‘，可能会导致数据丢失）

[root@server8 ~]为主库
[root@server9 ~]为从库

[root@server8 ~]上：
1 mysql安装包
mysql-community-client-5.7.17-1.el6.x86_64.rpm
mysql-community-common-5.7.17-1.el6.x86_64.rpm
mysql-community-libs-5.7.17-1.el6.x86_64.rpm
mysql-community-libs-compat-5.7.17-1.el6.x86_64.rpm
mysql-community-server-5.7.17-1.el6.x86_64.rpm

2 安装这5个mysql包
[root@server8 ~]# yum install -y mysql-community-client-5.7.17-1.el6.x86_64.rpm mysql-community-common-5.7.17-1.el6.x86_64.rpm mysql-community-libs-5.7.17-1.el6.x86_64.rpm mysql-community-libs-compat-5.7.17-1.el6.x86_64.rpm mysql-community-server-5.7.17-1.el6.x86_64.rpm

3 初始化mysql数据库
[root@server8 ~]# /etc/init.d/mysqld start
初始化 MySQL 数据库： [确定]
Installing validate password plugin: [确定]
正在启动 mysqld： [确定]

4 查询初始化密码（ -Hu#pa;oY8x8）
[root@server8 ~]# grep password /var/log/mysqld.log
2018-07-05T01:53:53.506087Z 1 [Note] A temporary password is generated for root@localhost: -Hu#pa;oY8x8
2018-07-05T01:54:55.290750Z 0 [Note] Execution of init_file ‘/var/lib/mysql/install-validate-password-plugin.ErrKj7.sql’ started.

5 修改初始化密码
[root@server8 ~]# mysql_secure_installation

Securing the MySQL server deployment.

Enter password for user root:

The existing password for the user account root has expired. Please set a new password.

New password:

Re-enter new password:
The ‘validate_password’ plugin is installed on the server.
The subsequent steps will run with the existing configuration
of the plugin.
Using existing password for root.

Estimated strength of the password: 100
Change the password for root ? ((Press y|Y for Yes, any other key for No) : n

… skipping.
By default, a MySQL installation has an anonymous user,
allowing anyone to log into MySQL without having to have
a user account created for them. This is intended only for
testing, and to make the installation go a bit smoother.
You should remove them before moving into a production
environment.

Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.

Normally, root should only be allowed to connect from
‘localhost’. This ensures that someone cannot guess at
the root password from the network.

Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
Success.

By default, MySQL comes with a database named ‘test’ that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.

Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
- Dropping test database…
Success.

Removing privileges on test database…
Success.

Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.

Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.

All done!
6 进入数据库
[root@server8 ~]# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.7.17 MySQL Community Server (GPL)

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>

7 修改配置文件（主库）
[root@server8 ~]# vim /etc/my.cnf
这里写图片描述

8 重起mysql服务，进入mysql
[root@server8 ~]# /etc/init.d/mysqld restart
停止 mysqld： [确定]
正在启动 mysqld： [确定]
[root@server8 ~]# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.17-log MySQL Community Server (GPL)

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>

10 授权此网段在所有库中拥有所有权限，并授予密码。
mysql> grant replication slave on . to repl@’172.25.16.%’ identified by’liYI1988618@’;
Query OK, 0 rows affected, 1 warning (0.66 sec)

13 新建westos数据库
mysql> create databases westos;

14 进入westos这个库创建表格
mysql> use westos
Database changed
mysql> create table usertb(
-> username varchar(20) not null, 行名字（username）字符数（20）不能为空
-> password varchar(25) not null); 行名字（password）字符数（25）不能为空

16 插入数据到建好的表格里
mysql> insert into usertb values (‘user1’,’123’);
Query OK, 1 row affected (0.31 sec)

mysql> insert into usertb values (‘user2’,’456’);
Query OK, 1 row affected (0.25 sec)

mysql> insert into usertb values (‘user3’,’789’);
Query OK, 1 row affected (0.12 sec)

[root@server9 ~]上：
1 mysql安装包
mysql-community-client-5.7.17-1.el6.x86_64.rpm
mysql-community-common-5.7.17-1.el6.x86_64.rpm
mysql-community-libs-5.7.17-1.el6.x86_64.rpm
mysql-community-libs-compat-5.7.17-1.el6.x86_64.rpm
mysql-community-server-5.7.17-1.el6.x86_64.rpm

2 安装这5个mysql包
[root@server9 ~]# yum install -y mysql-community-client-5.7.17-1.el6.x86_64.rpm mysql-community-common-5.7.17-1.el6.x86_64.rpm mysql-community-libs-5.7.17-1.el6.x86_64.rpm mysql-community-libs-compat-5.7.17-1.el6.x86_64.rpm mysql-community-server-5.7.17-1.el6.x86_64.rpm

3 初始化mysql数据库
[root@server9 ~]# /etc/init.d/mysqld start
初始化 MySQL 数据库： [确定]
Installing validate password plugin: [确定]
正在启动 mysqld： [确定]

4 查询初始化密码（ -Hu#pa;oY8x8）
[root@server9 ~]# grep password /var/log/mysqld.log
2018-07-05T0
1:53:53.506087Z 1 [Note] A temporary password is generated for root@localhost: 54:03.978482Z
2018-07-05T01:54:55.290750Z 0 [Note] Execution of init_file ‘/var/lib/mysql/install-validate-password-plugin.ErrKj7.sql’ started.

5 修改初始化密码
[root@server9 ~]# mysql_secure_installation

Securing the MySQL server deployment.

Enter password for user root:

The existing password for the user account root has expired. Please set a new password.

New password:

Re-enter new password:
The ‘validate_password’ plugin is installed on the server.
The subsequent steps will run with the existing configuration
of the plugin.
Using existing password for root.

Estimated strength of the password: 100
Change the password for root ? ((Press y|Y for Yes, any other key for No) : n

Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
Success.

Normally, root should only be allowed to connect from
‘localhost’. This ensures that someone cannot guess at
the root password from the network.

Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
Success.

By default, MySQL comes with a database named ‘test’ that
anyone can access. This is also intended only for testing,
and should be removed before moving into a production
environment.

Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
- Dropping test database…
Success.

Removing privileges on test database…
Success.

Reloading the privilege tables will ensure that all changes
made so far will take effect immediately.

Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y
Success.

All done!
6 进入数据库
[root@server9 ~]# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.7.17 MySQL Community Server (GPL)

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>

7 修改配置文件（从库）
[root@server9 ~]# vim /etc/my.cnf
这里写图片描述

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>

9 连接主库
mysql> change master to master_host=’172.25.16.8’,master_user=’repl’,master_password=’liYI1988618@’,master_log_file=’mysql-bin.000001’, master_log_pos=740;
Query OK, 0 rows affected, 2 warnings (1.13 sec)

10 启动slave，查看从库slave状态。
mysql> start slave;
Query OK, 0 rows affected (0.55 sec)

mysql> show slave status\G;
***************** 1. row *****************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.25.16.8
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 740
Relay_Log_File: server9-relay-bin.000002
Relay_Log_Pos: 320
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: 740
Relay_Log_Space: 529
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: 452bddba-7ff6-11e8-b28f-525400484d0b
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)
*注意：当看到Slave_IO_Running: Yes以及Slave_SQL_Running: Yes，则表示slave库已经正常运行了
当出现Slave_IO_Running: Connecting的提示时，说明主库和从库没有连接上，有以下三点原因：
1.网络问题：检查网络连接是否能够连接上
2.密码或POS号错误：查看pos号和主库的号是否对应
3.防火墙的问题：查看主库防火墙的策略，数据库是否拒绝外来连接，然后做相应的改动

二：mysql半同步
1 主库加载 master 模块并且开启:
mysql> install plugin rpl_semi_sync_master soname ‘semisync_master.so’;（加载模块）
Query OK, 0 rows affected (0.48 sec)

mysql> set global rpl_semi_sync_master_enabled=1;（开启）
Query OK, 0 rows affected (0.00 sec)

2 从库加载 master 模块并且开启:
mysql> install plugin rpl_semi_sync_slave soname ‘semisync_slave.so’;（加载模块）
Query OK, 0 rows affected (0.21 sec)

mysql> set global rpl_semi_sync_slave_enabled=1;（开启）
Query OK, 0 rows affected (0.00 sec)

注意：rpl_semi_sync_master_enabled 控制 master 是否开启半同步;
rpl_semi_sync_master_timeout 控制 master 等待多久被告知 slave 已经收到;即超时时间;
rpl_semi_sync_slave_enabled 控制 master 是否开启半同步;

5 主库上查看Value
mysql> show status like ‘%semi%’;
+——————————————–+——-+
| Variable_name | Value |
+——————————————–+——-+
| Rpl_semi_sync_master_clients | 1 |（检测到一个与主库连接的从库）
| Rpl_semi_sync_master_net_avg_wait_time | 0 |
| Rpl_semi_sync_master_net_wait_time | 0 |
| Rpl_semi_sync_master_net_waits | 3 |
| Rpl_semi_sync_master_no_times | 1 |
| Rpl_semi_sync_master_no_tx | 2 |
| Rpl_semi_sync_master_status | ON |
| Rpl_semi_sync_master_timefunc_failures | 0 |
| Rpl_semi_sync_master_tx_avg_wait_time | 465 |
| Rpl_semi_sync_master_tx_wait_time | 465 |
| Rpl_semi_sync_master_tx_waits | 1 |
| Rpl_semi_sync_master_wait_pos_backtraverse | 0 |
| Rpl_semi_sync_master_wait_sessions | 0 |
| Rpl_semi_sync_master_yes_tx | 1 |
+——————————————–+——-+
14 rows in set (0.00 sec)
Rpl_semi_sync_master_clients:查看有多少个开启半同步复制的插件的 slave;此
时只有一个;
Rpl_semi_sync_master_status: 查看 master 上半同步复制是否正在运行;值为
ON,说明正在运行,并且已被告知有 slave 收到;为 OFF 时,说明 master 未启用半同
步,或者没有被告知;
Rpl_semi_sync_master_no_tx:查看有多少事务没有经过半同步复制的机制进行复
制;
Rpl_semi_sync_master_yes_tx:查看有多少事务经过半同步复制的机制进行复制;

如果显示Rpl_semi_sync_slave_status 为OFF
执行 mysql> stop slave io_thread;此名令，关掉io模块

Rpl_semi_sync_slave_status: 查看 slave 上半同步复制是否正常运行,值为 ON
时,说明 slave 正通过半同步复制且 slave I/O 正在运行;为 OFF 时,反之。

7 实验：
在主从半同步开启的状态下,在主库上建立数据库,速度非常快,用了 0.12s
mysql> create database chaoren1;
Query OK, 1 row affected (0.12 sec)

关闭从服务:
mysql> stop slave;
Query OK, 0 rows affected (0.41 sec)

mysql> set global rpl_semi_sync_slave_enabled=0;
Query OK, 0 rows affected (0.00 sec)

主库再次创建数据库的时候会等待,当超时时间过了以后才再次创建(timoeout :
10000ms 即 10s)
mysql> create database chaoren2;
Query OK, 1 row affected (10.10 sec)

一旦超时,他就自动降级为异步,再次创建数据库的时候也不再等待
mysql> create database chaoren3;
Query OK, 1 row affected (0.16 sec)

此时查看主库 slave,已经不存在了:(第一行,value 值为 0,没有 slave)
mysql> show status like ‘%semi%’;
+——————————————–+——-+
| Variable_name | Value |
+——————————————–+——-+
| Rpl_semi_sync_master_clients | 0 |
| Rpl_semi_sync_master_net_avg_wait_time | 0 |
| Rpl_semi_sync_master_net_wait_time | 0 |
| Rpl_semi_sync_master_net_waits | 2 |
| Rpl_semi_sync_master_no_times | 1 |
| Rpl_semi_sync_master_no_tx | 2 |
| Rpl_semi_sync_master_status | OFF |
| Rpl_semi_sync_master_timefunc_failures | 0 |
| Rpl_semi_sync_master_tx_avg_wait_time | 465 |
| Rpl_semi_sync_master_tx_wait_time | 465 |
| Rpl_semi_sync_master_tx_waits | 1 |
| Rpl_semi_sync_master_wait_pos_backtraverse | 0 |
| Rpl_semi_sync_master_wait_sessions | 0 |
| Rpl_semi_sync_master_yes_tx | 1 |
+——————————————–+——-+
14 rows in set (0.00 sec)

主库查看 slave,又变成了 1:
mysql> show status like ‘%semi%’;
+——————————————–+——-+
| Variable_name | Value |
+——————————————–+——-+
| Rpl_semi_sync_master_clients | 1 |
| Rpl_semi_sync_master_net_avg_wait_time | 0 |
| Rpl_semi_sync_master_net_wait_time | 0 |
| Rpl_semi_sync_master_net_waits | 3 |
| Rpl_semi_sync_master_no_times | 1 |
| Rpl_semi_sync_master_no_tx | 2 |
| Rpl_semi_sync_master_status | ON |
| Rpl_semi_sync_master_timefunc_failures | 0 |
| Rpl_semi_sync_master_tx_avg_wait_time | 465 |
| Rpl_semi_sync_master_tx_wait_time | 465 |
| Rpl_semi_sync_master_tx_waits | 1 |
| Rpl_semi_sync_master_wait_pos_backtraverse | 0 |
| Rpl_semi_sync_master_wait_sessions | 0 |
| Rpl_semi_sync_master_yes_tx | 1 |
+——————————————–+——-+
14 rows in set (0.00 sec)

数据库复制的半同步方式的架构已经实现。

mysql5.7主从复制 半同步.....

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