详解MySQL主从复制实战 - 基于日志点的复制

2024-07-24 13:12:33

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基于日志点的复制

1、在主库与从库上建立专用的复制账号

MariaDB [employees]> create user 'repl'@'172.%' identified by '123456';

注意在生产上的密码必须依照相关规范以达到一定的密码强度, 并且规定在从库上的特定网段上才能访问主库

2、在主库与从库上授予复制权限

MariaDB [employees]> grant replication slave on *.* to 'repl'@'172.%';

3、配置主库

注意启用二进制日志需要重启服务, 而server_id是一个动态参数, 可以结合命令行与配置文件以达到免重启的持久化配置. 注意server_id在集群中是唯一的.

[mysqld]log_bin = /var/log/mysql/mariadb-binlog_bin_index = /var/log/mysql/mariadb-bin.indexbinlog_format = rowserver_id = 101

NOTE: 把日志与数据分开是个好习惯, 最好能放到不同的数据分区

4、配置从库

选项log_slave_update决定是否把中继日志relay_log存放到本机的binlog中, 如果是配置链路复制, 那么该选项必填. 注意server_id在集群中是唯一的.

[mysqld]# replicationlog_bin = /var/log/mysql/mariadb-binlog_bin_index = /var/log/mysql/mariadb-bin.indexserver_id = 102# slavesrelay_log    = /var/log/mysql/relay-binrelay_log_index  = /var/log/mysql/relay-bin.indexrelay_log_info_file  = /var/log/mysql/relay-bin.infolog_slave_updates = ONread_only

5、初始化从库的数据

此处使用mysqldump在主库上进行备份, 在生产上建议大家用xtrabackup进行无锁的热备(基于innodb引擎).

备份主库上的employees数据库的数据

复制代码代码如下:

	
	mysqldump --single-transaction --master-data=1 --triggers --routines --databases employees -u root -p >> backup.sql

将备份文件backup.sql通过scp或者docker volume卷挂载到从服务器上, 并且导入至从库中

mysql -u root -p < backup.sql

6、启动复制链路

现有master@172.20.0.2和slave@172.20.0.3, 并且已经通过mysqldump将数据同步至从库slave中. 现在在从服务器slave上配置复制链路

MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='master', MASTER_USER='repl', MASTER_PASSWORD='123456', MASTER_LOG_FILE='mariadb-bin.000029', MASTER_LOG_POS=516;Query OK, 0 rows affected (0.02 sec)

在从库上启动复制链路

MariaDB [(none)]> start slave;Query OK, 0 rows affected (0.01 sec)

7、在从库上检查slave状态

Slave_IO_Running与Slave_SQL_Running必须为YES, 如果出现错误须详细阅读Last_IO_Error或Last_SQL_Error的提示信息

MariaDB [(none)]> show slave status/G*************************** 1. row ***************************        Slave_IO_State: Waiting for master to send event         Master_Host: master         Master_User: repl         Master_Port: 3306        Connect_Retry: 60       Master_Log_File: mariadb-bin.000029     Read_Master_Log_Pos: 516        Relay_Log_File: relay-bin.000002        Relay_Log_Pos: 539    Relay_Master_Log_File: mariadb-bin.000029       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: 516       Relay_Log_Space: 831       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: 101        Master_SSL_Crl:      Master_SSL_Crlpath:          Using_Gtid: No         Gtid_IO_Pos:   Replicate_Do_Domain_Ids: Replicate_Ignore_Domain_Ids:        Parallel_Mode: conservative1 row in set (0.00 sec)

8、在主库检查dump线程

检测是否已经正确启动binlog dump线程

MariaDB [(none)]> show processlist /G*************************** 1. row ***************************   Id: 7  User: root  Host: 172.20.0.1:41868   db: employees Command: Sleep  Time: 56  State:  Info: NULLProgress: 0.000*************************** 2. row ***************************   Id: 10  User: repl  Host: 172.20.0.3:45974   db: NULL Command: Binlog Dump  Time: 246  State: Master has sent all binlog to slave; waiting for binlog to be updated  Info: NULLProgress: 0.000

可以看到row 2上有Command为Binlog Dump的命令被启动, 证明复制线程已经被成功启动

9、总结

优点