MySQL的主从复制

Posted 2020-09-06

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当业务扩展到一定程度时，服务器的负载能力往往不能胜任当前的业务规模，解决的方法无非是横向扩展和纵向扩展：

横向扩展：又称水平扩展（Scale Out），是通过负载均衡的方式，将压力疏散到后端各个节点服务器；

纵向扩展：又称垂直扩展（Scale Up），简单提高服务器的硬件性能，此方法很容易再次出现性能瓶颈现象。

数据库服务器在涉及到均衡调度时通常会遇到很多不可忽视的问题：

数据库服务器数据的一致性；

多个事务提交导致的数据完整性的保证；

服务器宕机，怎么保证事务正常提交等等。

数据同步方面，一般得解决方案有一下几种：

同步复制 (Synchronous Replication)：发生写数据时，主服务器需要等待从服务器同步完成之后才会返回给客户端信息，等待过程中为阻塞状态，所以效率极低；

半同步复制 (Asynchronous Replication)：发生写数据时，主服务器只同步给其中一台从服务器，半同步给其他从服务器；

异步复制 (Semisynchronous Replication)：发生写数据时，主服务器在从服务器同步数据的同时，向客户端返回信息，这种方式可能导致主从服务器数据不一致，或者从服务器数据同步状态严重落后于主服务器上的数据。

mysql主从复制模式：Master/Slave、Master/Master

Master/Slave：一主多从模式，由于从服务器只有只读权限，所以此种模式只能有效分担读请求的压力，但不能分担写请求；此种模式会带来数据同步一致性的问题，可能从服务器同步的数据进度远落后于主服务器更新的进度；如果主机宕机后，则数据就无法写入。

Master/Master：多主模式，多台服务器互为主从；这种模式会带来数据更新不一致，从而发生冲突的问题。

主/从工作流程：

建立主从关系后，如果主服务器发生Data Change之后，Binary Log会更新日志记录；从服务器通过I/O Thread读取主服务器上的Binary Log保存至本地的 Relay Log中，再通过SQL Thread执行本地Relay Log中的SQL语句，并将执行后的数据保存至磁盘中。

示例一：MySQL异步复制实现

配置文件：

Master:node7配置文件：

[mysqld]

datadir=/var/lib/mysql

socket=/var/lib/mysql/mysql.sock

symbolic-links=0

innodb_file_per_table=1

skip_name_resolve=ON

log_bin=master-log #开启二进制日志

server_id=1 #设置serverID

[mysqld_safe]

log-error=/var/log/mariadb/mariadb.log

pid-file=/var/run/mariadb/mariadb.pid

Slave:node8配置文件：

[mysqld]

datadir=/var/lib/mysql

socket=/var/lib/mysql/mysql.sock

symbolic-links=0

relay-log=relay-log #开启relay日志

innodb_file_per_table=1

read-only=1 #设置为只读

server_id=2 #设置serverID，必须不同于其他serverID

[mysqld_safe]

log-error=/var/log/mariadb/mariadb.log

pid-file=/var/run/mariadb/mariadb.pid

启动mariaDB：

[[email protected] ~]# systemctl start mariadb.service

从服务器需要主服务器授权一个具有REPLICATION SLAVE, REPLICATION CLIENT权限的用户：

MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO ‘hisen‘@‘192.168.17.%‘ IDENTIFIED BY ‘hisen‘;

MariaDB [(none)]> FLUSH PRIVILEGES;

MariaDB [(none)]> SHOW MASTER STATUS; #记录此时的binlog文件及位置，从服务器即将从此处进行同步

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

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

| master-log.000003 | 492 | | |

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

1 row in set (0.00 sec)

从服务器开始做同步复制的配置：

MariaDB [(none)]> CHANGE MASTER TO

-> MASTER_HOST=‘192.168.17.70‘,

-> MASTER_USER=‘hisen‘,

-> MASTER_PASSWORD=‘hisen‘,

-> MASTER_LOG_FILE=‘master-log.000003‘,

-> MASTER_LOG_POS=492;

Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> SHOW SLAVE STATUS\G; #查看从服务器状态

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

Slave_IO_State:

Master_Host: 192.168.17.70

Master_User: hisen

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: master-log.000003

Read_Master_Log_Pos: 492

Relay_Log_File: relay-log.000001

Relay_Log_Pos: 4

Relay_Master_Log_File: master-log.000003

Slave_IO_Running: No #IO-Thread没有启动

Slave_SQL_Running: No #SQL-Thread没有启动

MariaDB [(none)]> START SLAVE; 启动IO-Thread和SQL-Thread

Query OK, 0 rows affected (0.02 sec)

MariaDB [(none)]> SHOW SLAVE STATUS\G;

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

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.17.70 #主服务器地址

Master_User: hisen #复制时用到的用户名

Master_Port: 3306 #主服务器端口

Connect_Retry: 60 #重试连接时长

Master_Log_File: master-log.000003 #同步主服务器上的binlog文件

Read_Master_Log_Pos: 492 #binlog文件的位置

Relay_Log_File: relay-log.000002 #本地relay文件

Relay_Log_Pos: 530 #relay文件位置

Relay_Master_Log_File: master-log.000003

Slave_IO_Running: Yes #IO-Thread启动

Slave_SQL_Running: Yes #SQL-Thread启动

测试主从复制：

Master配置：

MariaDB [(none)]> CREATE DATABASE hisendb;

Query OK, 1 row affected (0.00 sec)

MariaDB [(none)]> USE hisendb;

Database changed

MariaDB [hisendb]> CREATE TABLE teachers (TID TINYINT NOT NULL PRIMARY KEY,Name VARCHAR(50),Age INT,Gender CHAR(10));

Query OK, 0 rows affected (0.02 sec)

MariaDB [hisendb]> INSERT INTO teachers VALUES (1,‘Mo Yuan‘,100,‘M‘),(2,‘Bai Qian‘,150,‘F‘),(3,‘Dong Huadijun‘,100,‘M‘);

Query OK, 3 rows affected (0.01 sec)

Records: 3 Duplicates: 0 Warnings: 0

MariaDB [hisendb]> SELECT * FROM teachers;

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

| TID | Name | Age | Gender |

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

| 1 | Mo Yuan | 100 | M |

| 2 | Bai Qian | 150 | F |

| 3 | Dong Huadijun | 100 | M |

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

3 rows in set (0.00 sec)

Slave端查看：

MariaDB [(none)]> SHOW DATABASES;

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

| Database |

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

| information_schema |

| hisendb |

| mysql |

| performance_schema |

| test |

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

5 rows in set (0.01 sec)

MariaDB [(none)]> USE hisendb;

Database changed

MariaDB [hisendb]> SELECT * FROM teachers;

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

| TID | Name | Age | Gender |

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

| 1 | Mo Yuan | 100 | M |

| 2 | Bai Qian | 150 | F |

| 3 | Dong Huadijun | 100 | M |

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

3 rows in set (0.00 sec)

对比可知，已经实现主从同步的效果！

再次查看Master信息：

MariaDB [(none)]> SHOW MASTER STATUS;

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

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

| master-log.000003 | 1008 | | |

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

1 row in set (0.00 sec)

再次查看Slave信息：

MariaDB [hisendb]> SHOW SLAVE STATUS\G;

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

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.17.70

Master_User: hisen

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: master-log.000003

Read_Master_Log_Pos: 1008 #已经跟Master的binlog位置相同

Relay_Log_File: relay-log.000002

Relay_Log_Pos: 1046

Relay_Master_Log_File: master-log.000003

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

示例二：MySQL半同步复制实现

需要插件支持：semisync_master.so、semisync_slave.so

主节点：

MariaDB [(none)]> INSTALL PLUGIN rpl_semi_sync_master SONAME ‘semisync_master.so‘;

Query OK, 0 rows affected (0.10 sec)

MariaDB [(none)]>

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE ‘rpl_semi%‘;

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

| Variable_name | Value |

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

| rpl_semi_sync_master_enabled | OFF |

| rpl_semi_sync_master_timeout | 10000 |

| rpl_semi_sync_master_trace_level | 32 |

| rpl_semi_sync_master_wait_no_slave | ON |

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

4 rows in set (0.00 sec)

MariaDB [(none)]> SET GLOBAL rpl_semi_sync_master_enabled=ON;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE ‘rpl_semi%‘;

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

| Variable_name | Value |

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

| rpl_semi_sync_master_enabled | ON | #半同步主节点开启

| rpl_semi_sync_master_timeout | 10000 | #主节点等待超时时间，默认10S

| rpl_semi_sync_master_trace_level | 32 |

| rpl_semi_sync_master_wait_no_slave | ON |

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

4 rows in set (0.00 sec)

MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO ‘hisen‘@‘192.168.17.%‘ IDENTIFIED BY ‘hisen‘;

MariaDB [(none)]> SHOW MASTER STATUS;

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

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

| master-log.000003 | 417 | | |

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

1 row in set (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL STATUS LIKE ‘%semi%‘;

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

| Variable_name | Value |

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

| Rpl_semi_sync_master_clients | 1 | #已经有一个半同步客户端

| Rpl_semi_sync_master_net_avg_wait_time | 0 |

| Rpl_semi_sync_master_net_wait_time | 0 |

| Rpl_semi_sync_master_net_waits | 0 |

| Rpl_semi_sync_master_no_times | 1 |

| Rpl_semi_sync_master_no_tx | 1 |

| Rpl_semi_sync_master_status | ON | #已经确认为半同步复制的主节点

| Rpl_semi_sync_master_timefunc_failures | 0 |

| Rpl_semi_sync_master_tx_avg_wait_time | 0 |

| Rpl_semi_sync_master_tx_wait_time | 0 |

| Rpl_semi_sync_master_tx_waits | 0 |

| Rpl_semi_sync_master_wait_pos_backtraverse | 0 |

| Rpl_semi_sync_master_wait_sessions | 0 |

| Rpl_semi_sync_master_yes_tx | 0 |

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

14 rows in set (0.01 sec)

从节点：

MariaDB [(none)]> INSTALL PLUGIN rpl_semi_sync_slave SONAME ‘semisync_slave.so‘;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE ‘rpl_semi%‘;

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

| Variable_name | Value |

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

| rpl_semi_sync_slave_enabled | OFF |

| rpl_semi_sync_slave_trace_level | 32 |

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

2 rows in set (0.00 sec)

MariaDB [(none)]> SET GLOBAL rpl_semi_sync_slave_enabled=ON;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE ‘rpl_semi%‘;

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

| Variable_name | Value |

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

| rpl_semi_sync_slave_enabled | ON |

| rpl_semi_sync_slave_trace_level | 32 |

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

2 rows in set (0.00 sec)

MariaDB [(none)]> CHANGE MASTER TO

-> MASTER_HOST=‘192.168.17.70‘,

-> MASTER_USER=‘hisen‘,

-> MASTER_PASSWORD=‘hisen‘,

-> MASTER_LOG_FILE=‘master-log.000003‘,

-> MASTER_LOG_POS=417;

Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> START SLAVE;

Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> SHOW SLAVE STATUS\G;

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

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.17.70

Master_User: hisen

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: master-log.000003

Read_Master_Log_Pos: 417

Relay_Log_File: relay-log.000002

Relay_Log_Pos: 530

Relay_Master_Log_File: master-log.000003

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

MariaDB [hisendb]> SHOW GLOBAL STATUS LIKE ‘%semi%‘;

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

| Variable_name | Value |

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

| Rpl_semi_sync_slave_status | ON | #已经确认为半同步复制中从节点

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

1 row in set (0.00 sec)

验证主从模式半同步复制：

Master节点：

MariaDB [(none)]> CREATE DATABASE hisendb;

Query OK, 1 row affected (0.00 sec)

MariaDB [(none)]> USE hisendb;

Database changed

MariaDB [hisendb]> CREATE TABLE teachers(TID INT NOT NULL PRIMARY KEY,Name VARCHAR(50) NOT NULL,Age INT ,Gender CHAR(1));

Query OK, 0 rows affected (0.01 sec)

MariaDB [hisendb]> INSERT INTO teachers VALUES (1,‘Ma Yun‘,55,‘M‘),(2,‘Ma Huateng‘,43,‘M‘),(3,‘Li Yanhong‘,49,‘M‘);

Query OK, 3 rows affected (0.01 sec)

Records: 3 Duplicates: 0 Warnings: 0

MariaDB [hisendb]> SELECT * FROM teahcers;

ERROR 1146 (42S02): Table ‘hisendb.teahcers‘ doesn‘t exist

MariaDB [hisendb]> SELECT * FROM teachers;

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

| TID | Name | Age | Gender |

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

| 1 | Ma Yun | 55 | M |

| 2 | Ma Huateng | 43 | M |

| 3 | Li Yanhong | 49 | M |

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

3 rows in set (0.00 sec)

MariaDB [hisendb]> SHOW GLOBAL STATUS LIKE ‘%semi%‘;

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

| Variable_name | Value |

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

| Rpl_semi_sync_master_clients | 1 |

| Rpl_semi_sync_master_net_avg_wait_time | 1500 |

| Rpl_semi_sync_master_net_wait_time | 4502 |

| Rpl_semi_sync_master_net_waits | 3 |

| Rpl_semi_sync_master_no_times | 1 |

| Rpl_semi_sync_master_no_tx | 1 |

| Rpl_semi_sync_master_status | ON |

| Rpl_semi_sync_master_timefunc_failures | 0 |

| Rpl_semi_sync_master_tx_avg_wait_time | 1592 |

| Rpl_semi_sync_master_tx_wait_time | 4777 |

| Rpl_semi_sync_master_tx_waits | 3 |

| Rpl_semi_sync_master_wait_pos_backtraverse | 0 |

| Rpl_semi_sync_master_wait_sessions | 0 |

| Rpl_semi_sync_master_yes_tx | 3 |

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

14 rows in set (0.00 sec)

Slave节点：

MariaDB [(none)]> USE hisendb

Database changed

MariaDB [hisendb]> SELECT * FROM teachers;

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

| TID | Name | Age | Gender |

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

| 1 | Ma Yun | 55 | M |

| 2 | Ma Huateng | 43 | M |

| 3 | Li Yanhong | 49 | M |

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

3 rows in set (0.00 sec)

到此主从模式的半同步复制已经成功，但是如果主节点与从节点的IO-Thread停止通信，则主节点会等待一个超时时间，然后自动降级为异步复制模式：

关闭从节点Slave功能：

MariaDB [hisendb]> STOP SLAVE;

Query OK, 0 rows affected (0.01 sec)

MariaDB [hisendb]> SHOW SLAVE STATUS\G;

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

Slave_IO_State:

Master_Host: 192.168.17.70

Master_User: hisen

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: master-log.000003

Read_Master_Log_Pos: 932

Relay_Log_File: relay-log.000002

Relay_Log_Pos: 1045

Relay_Master_Log_File: master-log.000003

Slave_IO_Running: No #IO-Tread关闭

Slave_SQL_Running: No #SQL-Thread关闭

主节点再插入数据，会等待10s的半同步超时时间：

MariaDB [hisendb]> INSERT INTO teachers VALUES (4,‘Lei Jun‘,44,‘M‘);

Query OK, 1 row affected (10.00 sec)

查看主节点半同步信息：

MariaDB [hisendb]> SHOW GLOBAL STATUS LIKE ‘%semi%‘;

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

| Variable_name | Value |

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

| Rpl_semi_sync_master_clients | 1 |

| Rpl_semi_sync_master_net_avg_wait_time | 1194 |

| Rpl_semi_sync_master_net_wait_time | 4777 |

| Rpl_semi_sync_master_net_waits | 4 |

| Rpl_semi_sync_master_no_times | 2 |

| Rpl_semi_sync_master_no_tx | 2 |

| Rpl_semi_sync_master_status | OFF | #关闭半同步主节点功能

| Rpl_semi_sync_master_timefunc_failures | 0 |

| Rpl_semi_sync_master_tx_avg_wait_time | 1592 |

| Rpl_semi_sync_master_tx_wait_time | 4777 |

| Rpl_semi_sync_master_tx_waits | 3 |

| Rpl_semi_sync_master_wait_pos_backtraverse | 0 |

| Rpl_semi_sync_master_wait_sessions | 0 |

| Rpl_semi_sync_master_yes_tx | 3 |

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

14 rows in set (0.01 sec)

示例三：MySQL双主模式实现：

MySQL的双主模式，其实就是服务器互为主从关系的模式，都拥有写数据的权限，也就是说双方都分别拥有binlog和relaylog。但是双主模式会带来不少问题，也容易造成数据不一致的情况。

由于双主/多主服务器都能对同一表进行插入新数据，如果有id属性，可能会造成双主服务器插入数据冲突，这种问题可以通过自增长id来解决，但是看起来并没像想象中那么美好：

从上图可以看出，按照自增长id的方式，ID号出现“间隙”。主主模式在使用时，问题多多，所以生产环境中MySQL一般都使用主从模式，主主模式可以作为了解MySQL同步数据其中的一种方式而已。

实验拓扑：

配置主要节点：

MySQL服务启动前，配置文件设定：

(1)sever_id必须不同；

(2)双方都需要启用binlog和relaylog；

(3)存在自增长id的表，为了使得id不冲突，需要定义自动增长方式：

一个节点使用奇数id

auto_increment_offset=1

auto_increment_increment=2

另一个节点使用偶数id

auto_increment_offset=2

auto_increment_increment=2

MySQL服务启动后：

(1)双方都需要有复制权限的用户；

(2)双方都需要指向对方为自己的主节点。

实验过程：

node7文件配置：

[mysqld]

datadir=/var/lib/mysql

socket=/var/lib/mysql/mysql.sock

symbolic-links=0

thread_handling=pool-of-threads

innodb_file_per_table=1

skip_name_resolve=ON

log_bin=master-log #开启binlog

relay-log=relay-log #开启relay log

auto_increment_offset=1 #自增长id初始值

auto_increment_increment=2 #自增长id步进

server_id=1 #serverID

node8文件配置：

[mysqld]

datadir=/var/lib/mysql

socket=/var/lib/mysql/mysql.sock

symbolic-links=0

relay-log=relay-log #开启relay log

innodb_file_per_table=1

server_id=2 #serverID

log_bin=master-log #开启binlog

auto_increment_offset=2 #自增长id初始值

auto_increment_increment=2 #自增长id步进

①启动MySQL服务：

[[email protected] ~]# systemctl start mariadb.service

②各自创建一个拥有复制权限的用户：

node7 :

MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO ‘hisen‘@‘192.168.17.%‘ IDENTIFIED BY ‘hisen‘;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> FLUSH PRIVILEGES;

Query OK, 0 rows affected (0.11 sec)

node8:

MariaDB [(none)]> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO ‘hisen‘@‘192.168.17.%‘ IDENTIFIED BY ‘hisen‘;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> FLUSH PRIVILEGES;

Query OK, 0 rows affected (0.00 sec)

③查看双方当前使用的binlog及位置：

node7：

MariaDB [(none)]> SHOW MASTER STATUS;

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

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

| master-log.000003 | 502 | | |

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

1 row in set (0.00 sec)

node8：

MariaDB [(none)]> SHOW MASTER STATUS;

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

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

| master-log.000003 | 502 | | |

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

1 row in set (0.00 sec)

④各自指向对方的服务器为自己的主节点：

node7 :

MariaDB [(none)]> CHANGE MASTER TO

-> MASTER_HOST=‘192.168.17.80‘,

-> MASTER_USER=‘hisen‘,

-> MASTER_PASSWORD=‘hisen‘,

-> MASTER_LOG_FILE=‘master-log.000003‘,

-> MASTER_LOG_POS=502;

Query OK, 0 rows affected (0.04 sec)

node8：

MariaDB [(none)]> CHANGE MASTER TO

-> MASTER_HOST=‘192.168.17.70‘,

-> MASTER_USER=‘hisen‘,

-> MASTER_PASSWORD=‘hisen‘,

-> MASTER_LOG_FILE=‘master-log.000003‘,

-> MASTER_LOG_POS=502;

Query OK, 0 rows affected (0.02 sec)

⑤开启SLAVE，并查看SLAVE状态：

node7：

MariaDB [(none)]> START SLAVE;

Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> SHOW SLAVE STATUS\G;

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

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.17.80 #主节点为对方IP

Master_User: hisen

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: master-log.000003

Read_Master_Log_Pos: 502

Relay_Log_File: relay-log.000002

Relay_Log_Pos: 530

Relay_Master_Log_File: master-log.000003

Slave_IO_Running: Yes #已经开启IO-Thread

Slave_SQL_Running: Yes #已经开启SQL-Thread

node8：

MariaDB [(none)]> START SLAVE;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SHOW SLAVE STATUS\G;

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

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.17.70 #主节点为对方IP

Master_User: hisen

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: master-log.000003

Read_Master_Log_Pos: 502

Relay_Log_File: relay-log.000002

Relay_Log_Pos: 530

Relay_Master_Log_File: master-log.000003

Slave_IO_Running: Yes #已经开启IO-Thread

Slave_SQL_Running: Yes #已经开启SQL-Thread

⑥测试主主数据复制：

创建数据库hisendb，并创建friends表：

MariaDB [(none)]> CREATE DATABASE hisendb;

Query OK, 1 row affected (0.01 sec)

MariaDB [hisendb]> CREATE TABLE friends(ID INT UNSIGNED PRIMARY KEY AUTO_INCREMENT,Name VARCHAR(50) NOT NULL,Age TINYINT,Gender ENUM(‘F‘,‘M‘));

Query OK, 0 rows affected (0.09 sec)

首先在node7主节点插入 (‘Xu He‘,25,‘M‘),(‘Xu Mingying‘,27,‘F‘):

MariaDB [hisendb]> INSERT INTO friends(Name,Age,Gender) VALUES (‘Xu He‘,25,‘M‘),(‘Xu Mingying‘,27,‘F‘);

Query OK, 2 rows affected (0.17 sec)

Records: 2 Duplicates: 0 Warnings: 0

MariaDB [hisendb]> SELECT * FROM friends;

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

| ID | Name | Age | Gender |

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

| 1 | Xu He | 25 | M |

| 3 | Xu Mingying | 27 | F |

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

2 rows in set (0.00 sec)

再次在node8主节点插入(‘Tian Tao‘,26,‘M‘),(‘Liang Juntao‘,27,‘M‘):

MariaDB [hisendb]> INSERT INTO friends(Name,Age,Gender) VALUES (‘Tian Tao‘,26,‘M‘),(‘Liang Juntao‘,27,‘M‘);

Query OK, 2 rows affected (0.00 sec)

Records: 2 Duplicates: 0 Warnings: 0

MariaDB [hisendb]> SELECT * FROM friends;

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

| ID | Name | Age | Gender |

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

| 1 | Xu He | 25 | M |

| 3 | Xu Mingying | 27 | F |

| 4 | Tian Tao | 26 | M |

| 6 | Liang Juntao | 27 | M |

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

4 rows in set (0.00 sec)

由上可知，双方能完成数据同步，但是自增长ID的确出现“间隙”。

本文出自 “DevOps” 博客，请务必保留此出处http://hisen2devops.blog.51cto.com/10109340/1909315

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