mysql的主从复制

所有的关系型数据库都存在一个通病性能差，在企业中如果用户量特别打，将所有的数据都存放在一台服务器上，其性能时远远达不到要求的。所以需要使用一些手段来解决其性能的问题。

提升性能的方式有向上扩展以及向外扩展 向上扩展(Scale Up):使用更新更好的硬件，但硬件在怎么更新也有其性能的极限。盲目的向上扩展无法结局根本的问题 向外扩展(Scale Out):就是使用多台机器分摊压力来提供服务

主从复制就是拿多个数据库服务器，组合成一个服务器的集合对外共同服务实现性能的提升，逻辑上使用的时对外扩展的方式(Scale out)来提升服务器的性能。

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新主机搭建主从复制搭建

服务器类型	ip地址
主	192.168.73.133
从	192.168.73.145

主服务器操作

1.在主服务器上启用二进制日志

[root@localhost ~]# vim /etc/mysql/my.cnf log-bin=/data/bin/mysql-binbinlog-format=rowserver-id=1

2.创建二进制日志目录

[root@localhost ~]# mkdir /data/bin[root@localhost ~]# chown -R mysql.mysql /data/bin

3.重启服务

[root@localhost ~]# service mysqld restartRestarting mysqld (via systemctl):                         [  OK  ]

4.创建一个用来让从服务器复制数据的账号

MariaDB [(none)]> GRANT REPLICATION SLAVE ON *.* TO repluser@'192.168.73.%' IDENTIFIED BY 'centos';Query OK, 0 rows affected (0.00 sec)

5.查看主服务器正在使用的二进制日志

MariaDB [(none)]> SHOW MASTER LOGS;+------------------+-----------+| Log_name         | File_size |+------------------+-----------+| mysql-bin.000001 |       515 |    #当前二进制文件及位置需要记录，从服务器设置时需要+------------------+-----------+1 row in set (0.00 sec)

从服务器操作

1.修改配置文件

server-id       = 2     #server-id改为和主服务器不同read-only               #设置为只读#log-bin=mysql-bin      #将二进制日志关闭

2.启动MySQL服务器

[root@localhost ~]# service mysqld restartStarting mysqld (via systemctl):                           [  OK  ]

3.关联主服务器

MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='192.168.73.133',MASTER_USER='repluser',MASTER_PASSWORD='centos',MASTER_PORT=3306,MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=515;Query OK, 0 rows affected (0.01 sec)

4.查看从服务器状态

MariaDB [(none)]> SHOW SLAVE STATUS\G;*************************** 1. row ***************************               Slave_IO_State:                   Master_Host: 192.168.73.133                  Master_User: repluser                  Master_Port: 3306                Connect_Retry: 60              Master_Log_File: mysql-bin.000001          Read_Master_Log_Pos: 515               Relay_Log_File: localhost-relay-bin.000001                Relay_Log_Pos: 4        Relay_Master_Log_File: mysql-bin.000001             Slave_IO_Running: No            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: 0                   Last_Error:                  Skip_Counter: 0          Exec_Master_Log_Pos: 515              Relay_Log_Space: 256              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: NULLMaster_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: 0               Master_SSL_Crl:            Master_SSL_Crlpath:                    Using_Gtid: No                  Gtid_IO_Pos:       Replicate_Do_Domain_Ids:   Replicate_Ignore_Domain_Ids:                 Parallel_Mode: conservative                    SQL_Delay: 0          SQL_Remaining_Delay: NULL      Slave_SQL_Running_State: 1 row in set (0.00 sec)ERROR: No query specified

5.启动线程

MariaDB [(none)]> START SLAVE;Query OK, 0 rows affected (0.00 sec)

测试

在主服务器上导入一个hellodb数据库

[root@localhost ~]# mysql < hellodb_innodb.sql

从服务器上查看是否同步成功

MariaDB [(none)]> SHOW DATABASES;+--------------------+| Database           |+--------------------+| hellodb            |      #已经有hellodb库| information_schema || mysql              || performance_schema || test               |+--------------------+5 rows in set (0.00 sec)

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主服务器已有数据的情况下搭建主从

拥有一台已经有数据的mysql服务器，追加一台从服务器

服务器	IP地址
Master	192.168.73.148
Slave	192.168.73.149

Master中的数据

[root@localhost ~]# mysql -e "SHOW DATABASES;"+--------------------+| Database           |+--------------------+| information_schema || hellodb            || mysql              || performance_schema || test               || test1              |+--------------------+

配置主服务器

1.修改主服务器配置文件

[root@localhost ~]# vim /etc/my.cnf[mysqld]log-bin=/data/bin/mysql-binbinlog-format=row[root@localhost ~]# systemctl restart mariadb

2.创建复制账号

[root@localhost ~]# mysql -e "GRANT REPLICATION SLAVE ON *.* TO 'repluser'@'192.168.73.%' IDENTIFIED BY 'centos';"

3.备份主节点中的所有数据

[root@localhost ~]# mysqldump -A --single-transaction -F --master-data=1 > /data/all.sql[root@localhost ~]# vim /data/all.sql

4.将备份数据传送给从节点

[root@localhost ~]# scp /data/all.sql 192.168.73.149:/data

配置从服务器

1.修改配置文件

[root@localhost ~]# vim /etc/my.cnf[mysqld]server-id=2read-only

2.清空MySQL数据库

[root@localhost ~]# rm -rf /var/lib/mysql/*

3.修改备份数据将chang master to 加入文件中

CHANGE MASTER TO  MASTER_HOST='192.168.73.148',  MASTER_USER='repluser',  MASTER_PASSWORD='centos',  MASTER_PORT=3306,  MASTER_LOG_FILE='mysql-bin.000005',  MASTER_LOG_POS=245;

4.启动MySQL服务，并导入备份

[root@localhost ~]# mysql < /data/all.sql

5.查看从节点状态

MariaDB [(none)]> SHOW SLAVE STATUS\G;*************************** 1. row ***************************               Slave_IO_State:                   Master_Host: 192.168.73.148                  Master_User: repluser                  Master_Port: 3306                Connect_Retry: 60              Master_Log_File: mysql-bin.000005          Read_Master_Log_Pos: 245               Relay_Log_File: mariadb-relay-bin.000001                Relay_Log_Pos: 4        Relay_Master_Log_File: mysql-bin.000005             Slave_IO_Running: No            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: 0                   Last_Error:                  Skip_Counter: 0          Exec_Master_Log_Pos: 245              Relay_Log_Space: 245              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: NULLMaster_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: 01 row in set (0.00 sec)

6.启动线程

MariaDB [(none)]> START SLAVE;Query OK, 0 rows affected (0.00 sec)

7.再次查看从节点状态，复制的2个线程已经启动

MariaDB [(none)]> SHOW SLAVE STATUS\G;*************************** 1. row ***************************               Slave_IO_State: Waiting for master to send event                  Master_Host: 192.168.73.148                  Master_User: repluser                  Master_Port: 3306                Connect_Retry: 60              Master_Log_File: mysql-bin.000005          Read_Master_Log_Pos: 245               Relay_Log_File: mariadb-relay-bin.000002                Relay_Log_Pos: 529        Relay_Master_Log_File: mysql-bin.000005             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: 245              Relay_Log_Space: 825              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: 0Master_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: 11 row in set (0.00 sec)

测试

主节点删test1库

MariaDB [(none)]> DROP DATABASE  test1;Query OK, 1 row affected (0.01 sec)

从节点查看是否同步

MariaDB [(none)]> SHOW DATABASES;+--------------------+| Database           |+--------------------+| information_schema || hellodb            || mysql              || performance_schema || test               |+--------------------+5 rows in set (0.00 sec)      #已经没有test1库