mysql主从同步/主主同步

Posted 2021-01-05

Centos环境
198.168.1.20
198.168.1.21

master操作：

修改mysql配置文件（my.cnf）

[mysqld]
server-id=1
log-bin=mysql-bin
binlog-do-db=xxx     //要同步的库
binlog-ignore-db=mysql   //不同步的
sync_binlog = 1      //类似实时存入binlog，=0则会先写进缓存
binlog_checksum = none   //此命令可以同步不同版本的mysql数据库，mysql5.6.5以后的版本中binlog_checksum默认值是crc32,
binlog_format = mixed
basedir = /usr/local/mysql
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock

---

锁定数据库
flush tables with read lock;
//此命令为只读锁，unlock tables命令解除锁定

---

导出要同步的库

 mysqldump  -uroot 库名 -p > /root/mobi.sql

---

rsync传输sql库
rsync -r "ssh -p22" -avpgolr /root/mobi.sql 192.168.1.21:/root

---

授权用户（测试注意防火墙的关闭）

grant replication slave,replication client on *.* to [email protected]‘192.168.1.21‘ identified by ‘123456‘;
flush privileges;

---

查看授权：
show grants for [email protected]‘192.168.1.21‘;

---

查看主服务器状态：

show master status;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000024 |       592 |              |                  |
+------------------+----------+--------------+------------------+

从服务器操作

修改配置文件my.cnf

server-id=2
log-bin=mysql-bin
replicate-do-db=mobi
replicate-ignore-db=mysql
slave-skip-errors = all
basedir = /usr/local/mysql
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
user=mysql

如果有库则先dump下备份，避免操作失误

mysqldump  -uroot 要备份的库 -p > /root/要备份的库.sql.bak
drop 要备份的库;

创建空库然后导入

mysql> create database 要备份的库;
mysql> use mobi;
mysql> source /root/要备份的库.sql

额外内容（同步表内容）：

当只针对某些库的某张表进行同步时，如下，只同步huanqiu库的haha表和huanpc库的heihei表：
replicate-do-db = 库名
replicate-wild-do-table = 库名.表名       //当只同步几个或少数表时，可以这样设置。注意这要跟上面的库指定配合使用；
replicate-do-db = 库名
replicate-wild-do-table = 库名.表名      //如果同步的库的表比较多时，就不能这样一一指定了，就把这个选项配置去掉，直接根据指定的库进行同步。

=================================

配置主从指令：

mysql> stop slave;（同步前先关闭）
mysql> change  master to master_host=‘192.168.1.20‘,master_user=‘root‘,master_password=‘123456‘,master_log_file=‘mysql-bin.000024‘,master_log_pos=592;
mysql> start slave;

---

从库先查看slave状态

show slave statusG;

看是不是两个yes 如果不是就有问题

测试阶段（主库）

mysql> unlock tables;  

//解锁
mysql> create table zhang (id,int)

从库查看
mysql> desc zws;
+---------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------+---------+------+-----+---------+-------+
| student | int(11) | YES | | NULL | |
+---------+---------+------+-----+---------+-------+

主主同步

=============================================================================

=============================================================================

master中修改

修改配置文件 my.cnf

server-id = 1        
log-bin = mysql-bin  
binlog-ignore-db = mysql,information_schema
sync_binlog = 1
binlog_checksum = none
binlog_format = mixed
auto-increment-increment = 2    
auto-increment-offset = 1   
slave-skip-errors = all 

授权用户：

mysql> grant replication slave,replication client on *.* to [email protected]‘192.168.1.21‘ identified by "123456";
mysql> flush privileges;

mysql> FLUSH TABLES WITH READ LOCK; //注意该参数设置后，如果自己同步对方数据，同步前一定要记得先解锁！

mysql> show master status; //查看主信息

slave库配置

修改配置文件my.cnf

[mysqld]
server-id=2
log-bin=mysql-bin
replicate-do-db=mobi
replicate-ignore-db=mysql
slave-skip-errors = all
sync_binlog = 1
binlog_checksum = none
binlog_format = mixed
auto-increment-increment = 2
auto-increment-offset = 2
slave-skip-errors = all
basedir = /usr/local/mysql
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
user=mysql

授权用户

mysql> grant replication slave ,replication client on *.* to [email protected]‘192.168.1.20‘ identified by "123456";  
mysql> flush privileges;
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000020 |      602 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

主库解锁

mysql> unlock tables;     //先解锁，将对方数据同步到自己的数据库中
mysql> stop slave ;
mysql> change master to master_host=‘192.168.1.20‘,master_user=‘root‘,master_password=‘123456‘,master_log_file=‘master-bin.000027‘,master_log_pos=150;
mysql> start slave;
mysql> show slave status G;

此处实现了slave--->master的功能

====================================================================

master---->slave功能

mysql> unlock tables;
mysql> stop slave ;
mysql> change master to master_host=‘192.168.1.21‘,master_user=‘root‘,master_password=‘123456‘,master_log_file=‘master-bin.000023‘,master_log_pos=150;
mysql> start slave;
mysql> show slave status G;

此刻完成

====================================================================

问题排错：
出现

Slave_IO_Running: No
Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: ‘Could not find first log file name in binary log index file‘

解决方案：
1）从库上执行
stop slave;
2）主库进行刷新日志
flush logs;
3）查看日志
mysql> show master statusG;
4）重新
CHANGE MASTER TO MASTER_LOG_FILE=‘mysql-bin.000114‘,MASTER_LOG_POS=120;
5）重启
start slave;