Mysql实例Mysql 主从数据库同步(centos篇)

发布时间：2020-12-12 01:31:58 所属栏目：MySql教程来源：网络整理

导读：《Mysql实例Mysql 主从数据库同步(centos篇)》要点：本文介绍了Mysql实例Mysql 主从数据库同步(centos篇)，希望对您有用。如果有疑问，可以联系我们。环境: 主服务器:centos 5.2 mysql 5.1.35 源码 IP:192.168.1.22 从服务器:centos 5.2 mysql 5.1.35 源码

《Mysql实例Mysql 主从数据库同步(centos篇)》要点：
本文介绍了Mysql实例Mysql 主从数据库同步(centos篇)，希望对您有用。如果有疑问，可以联系我们。

环境:

主服务器:centos 5.2 mysql 5.1.35 源码 IP:192.168.1.22 从服务器:centos 5.2 mysql 5.1.35 源码? IP:192.168.1.33

配置:

一、主服务器 ????1.1、创建一个复制用户,具有replication slave 权限. mysql>grant replication slave on *.* to 'repl'@'192.168.1.22' identified by 'repl'; ??? 1.2、编辑my.cnf文件 vi /etc/my.cnf
添加
server-id=1
并开启log-bin二进制日志文件
log-bin=mysql-bin 注:需要把默认的server-id=1去掉 ??? 1.3、启动mysql数据库 mysqld_safe --user=mysql & ??? 1.4、设置读锁 mysql>flush tables with read lock; ??? 1.5、得到binlog日志文件名和偏移量 mysql>show master status; +------------------+----------+--------------+------------------+
| File???????????? | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.0000010 |????? 106|????????????? |????????????????? |
+------------------+----------+--------------+------------------+ ??? 1.6、备份要同步的数据库 mysqldump test > test.sql ??? 1.7、解锁 mysql>unlock tables; ? 二、从服务器 ??????? 2.1、编辑my.cnf文件 vi /etc/my.cnf
添加
server-id=2 注:需要把默认的server-id=1去掉 ??? 2.2、启动从数据库 mysqld_safe --user=mysql & ??????? 2.3、对从数据库进行相应设置 mysql> change master to
????????-> master_host='192.168.1.22'
????????-> master_user='repl'
????????-> master_password='repl'
????????-> master_log_file='mysql-bin.0000010'
????????-> master_log_pos=106; ??????? 2.4、启动从服务器slave线程 mysql>start slave; 执行show processlist命令显示以下进程: mysql>show processlistG
*************************** 2. row ***************************
???????? Id: 2
???? User: system user
???? Host:????
???????? db: NULL
Command: Connect
???? Time: 2579
????State: Has read all relay log; waiting for the slave I/O thread to update it
???? Info: NULL 表示slave已经连接上master,开始接受并执行日志 ???????? 2.5、查看slave线程状态 mysql>show slave status; *************************** 1. row ***************************
?????????????? Slave_IO_State: Waiting for master to send event
????????????????? Master_Host: 192.168.1.22 ????????????????? Master_User: repl
????????????????? Master_Port: 3306
??????????????? Connect_Retry: 60
????????????? Master_Log_File: mysql-bin.0000010
????????? Read_Master_Log_Pos:?106
?????????????? Relay_Log_File: centos-relay-bin.000002
??????????????? Relay_Log_Pos: 529
??????? Relay_Master_Log_File: mysql-bin.0000010
???????????? 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:?106
????????????? Relay_Log_Space: 830
????????????? 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:
1 row in set (0.00 sec) ?

验证是否配置正确

在从服务器上执行 show slave statusG;
Waiting for master to send event
Slave_IO_Running: Yes
Slave_SQL_Running: Yes 如以上二行同时为Yes 说明配置成功
?

测试

1、在主服务器test数据库中创建user表 mysql>use test;
mysql>create table user(id int); 2、在从服务器中查看user表 mysql>use test;
mysql> show tables like 'user';
+----------------------+
| Tables_in_test(user)?|
+----------------------+
| user?????????????? ? |????
+----------------------+
1 row in set (0.00 sec) 说明主从数据同步成功. ?

问题?

1.在从数据库中查看slave状态时出现 The slave I/O thread stops because master and slave have equal MySQL server ids; these ids must be different for replication to work (or the --replicate-same-server-id option must be used on slave but this does not always make sense; please check the manual before using it) 说明方从服务器里my.cnf中的server-id有相同的. 解决办法: 修改my.cnf里的server-id,并重启数据库服务.my.cnf文件默认有server-id=1 ? 其它说明主服务器my.cnf #binlog-do-db=需要备份的数据库名,可写多行
#binlog-ignore-db=不需要备份的数据库名,可写多行
从服务器my.cnf # replicate-do-db=test??需要备份的数据库名
# replicate-ignore-db=mysql 忽略的数据库
# master-connect-retry=60 如果从服务器发现主服务器断掉,重新连接的时间差(秒) 以下设置也可直接修改my.cnf配置文件 log-bin=mysql-bin
master-host=192.168.1.22 master-user=repl master-password=repl
master-port=3306

主从服务器同步维护由于各种原因,导致主从数据不一致,在负载低的时候,进行手动同步. 在主服务器上执行 ? mysql>flush tables with read lock; Query OK,rows affected (0.01 sec) mysql>show master status; +------------------+----------+--------------+------------------+
| File???????????? | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.0000011 |????? 260|????????????? |????????????????? |
+------------------+----------+--------------+------------------+ 在从服务器上执行先得到当前主服务器的二进制文件名和偏移量,执行命令使从服务器与主服务器同步 mysql>select master_pos_wait('mysql-bin.0000011','260');
+--------------------------------------------------+
| master_pos_wait('mysql-bin.0000011','260')????????????|
+--------------------------------------------------+
|??0???????????????????????????????????????????????????????????????????|???
+--------------------------------------------------+
1 row in set (0.01 sec) 同步完成后,在主服务器上执行解锁 mysql>unlock tables; ? 切换主从服务器 ? 当主服务器出现故障时,可将从服务器当主服务器来使用.步骤如下: 1、保证所有从数据库都已经执行了relay log中的全部更新,在从服务器中执行 stop slave io_thread,用show processlist检查,查看状态是否是Has read all relay log,表示更新完成. mysql>stop slave io_thread;
Query OK,0 affected (0.00 sec)
mysql>show processlistG; *************************** 2. row ***************************
???? Id: 2
?? User: system user
?? Host:
???? db: NULL
Command: Connect
?? Time: 4757
? State: Has read all relay log; waiting for the slave I/O thread to update it
?? Info: NULL 2、在从服务器上执行stop slave,reset master命令,重置成主数据库 mysql>stop slave;
Query OK,0 affected (0.00 sec)
mysql>reset master;
Query OK,0 affected (0.00 sec)

3、删除新的主服务器数据库目录中的master.info和relay-log.info文件,否则下次重启时还会按照从服务器来启动. MYSQL实例

（编辑：李大同）

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