1,概述
主主復(fù)制,即在兩臺(tái)MySQL主機(jī)內(nèi)都可以變更數(shù)據(jù),而且另外一臺(tái)主機(jī)也會(huì)做出相應(yīng)的變更。聰明的你也許已經(jīng)想到該怎么實(shí)現(xiàn)了。對(duì),就是將兩個(gè)主從復(fù)制有機(jī)合并起來(lái)就好了。只不過(guò)在配置的時(shí)候我們需要注意一些問(wèn)題,例如,主鍵重復(fù),server-id不能重復(fù)等等。

2,實(shí)現(xiàn)過(guò)程
2.1,啟動(dòng)和配置mysql_master_a
啟動(dòng)docker容器,172.18.0.21
docker run -it --name mysql_master_a -h mysql_master_a \
-p 23306:3306 --net my_network --ip 172.18.0.21 \
mysql_master:v2 /bin/bash /etc/rc.local
修改配置Mysql配置文件
- 進(jìn)入mysql_master_a容器,配置/etc/mysql/mysql.conf.d/mysqld.cnf
server-id=1 #任意自然數(shù)n,只要保證兩臺(tái)MySQL主機(jī)不重復(fù)就可以了。
log-bin=mysql-bin #開(kāi)啟二進(jìn)制日志
auto_increment_increment=2 #步進(jìn)值auto_imcrement,一般有n臺(tái)主MySQL就填n
auto_increment_offset=1 #起始值,一般填第n臺(tái)主MySQL,此時(shí)為第一臺(tái)主MySQL
replicate-do-db=mall #要同步的數(shù)據(jù)庫(kù),默認(rèn)所有庫(kù)
expire_logs_days=7 # 只保存最近7天的bin-log文件,避免文件過(guò)多
- 修改配置之后,要重啟Mysql服務(wù)
service mysql restart
創(chuàng)建Mysql賬號(hào)
mysql> Grant all privileges on *.* to 'test'@'%' identified by '123456' with grant option;
mysql> Grant REPLICATION SLAVE on *.* to 'slave1'@'%' identified by '123456';
查看master狀態(tài),記錄bin-log文件名稱(chēng)和位置
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000004 | 747 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
2.2,啟動(dòng)和配置mysql_master_b
啟動(dòng)docker容器,172.18.0.22
docker run -it --name mysql_master_b -h mysql_master_b \
-p 23307:3306 --net my_network --ip 172.18.0.22 \
mysql_master:v2 /bin/bash /etc/rc.local
修改配置Mysql配置文件
- 進(jìn)入mysql_master_b容器,配置/etc/mysql/mysql.conf.d/mysqld.cnf
server-id=2
log-bin=mysql-bin
auto_increment_increment=2
auto_increment_offset=2
replicate-do-db=mall
- 修改配置之后,要重啟Mysql服務(wù)
service mysql restart
創(chuàng)建Mysql賬號(hào)
mysql> Grant all privileges on *.* to 'test'@'%' identified by '123456' with grant option;
mysql> Grant REPLICATION SLAVE on *.* to 'slave1'@'%' identified by '123456';
查看master狀態(tài),記錄bin-log文件名稱(chēng)和位置
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000004 | 747 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
2.3,在mysql_master_a和mysql_master_b分別告知另外一個(gè)Master信息,包含IP、用戶(hù)、密碼、bin-log文件名稱(chēng)和位置
- 在mysql_master_a(172.18.0.21)執(zhí)行
mysql> CHANGE MASTER TO
MASTER_HOST='172.18.0.22',
MASTER_USER='slave1',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000004',
MASTER_LOG_POS=747;
mysql> start slave;
mysql> show slave status\G;
- 在mysql_master_b(172.18.0.22)執(zhí)行
mysql> CHANGE MASTER TO
MASTER_HOST='172.18.0.21',
MASTER_USER='slave1',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000004',
MASTER_LOG_POS=747;
mysql> start slave;
mysql> show slave status\G;
3,測(cè)試
3.1,測(cè)試用例1
- 在mysql_master_a執(zhí)行數(shù)據(jù)庫(kù)test創(chuàng)建、數(shù)據(jù)表student創(chuàng)建、數(shù)據(jù)插入更新刪除等操作,確認(rèn)mysql_master_b是否有對(duì)應(yīng)的數(shù)據(jù)變化(結(jié)果一致)
- 相反,在mysql_master_b執(zhí)行類(lèi)似操作,確認(rèn)mysql_master_a是否有對(duì)應(yīng)的數(shù)據(jù)變化(結(jié)果一致)
mysql> create database mall;
mysql> CREATE TABLE mall.`student` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(255) CHARACTER SET utf8 DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
mysql> Insert into mall.student(name) values('aaa');
mysql> Insert into mall.student(name) values('bbb');
mysql> delete from mall.student where id = 1;
mysql> update mall.student set name = 'ccc' where id = 2;
mysql> drop table student;
mysql> drop database mall;
3.2,測(cè)試用例2
- 在mysql_master_a和mysql_master_b分別執(zhí)行多次insert操作
Insert into mall.student(name) values('aaa');
Insert into mall.student(name) values('bbb');
- 兩個(gè)Mysql服務(wù)的數(shù)據(jù)一致
mysql> select * from mall.student;
+----+------+
| id | name |
+----+------+
| 5 | aaa |
| 7 | bbb |
| 8 | aaa |
| 10 | bbb |
| 11 | aaa |
| 13 | bbb |
| 15 | aaa |
| 17 | bbb |
| 18 | aaa |
| 20 | bbb |
| 22 | aaa |
| 23 | aaa |
+----+------+
12 rows in set (0.00 sec)
- 查看student表結(jié)構(gòu),AUTO_INCREMENT會(huì)隨著insert自動(dòng)增加,因此保證id不會(huì)存在沖突
(但是,在高并發(fā)情況下,不能保證不會(huì)沖突,因此,此處設(shè)置自增步長(zhǎng)是master個(gè)數(shù),保證每臺(tái)master服務(wù)器的自增序列不重復(fù),因此不會(huì)存在主鍵沖突)
CREATE TABLE `student` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(255) CHARACTER SET utf8 DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=24 DEFAULT CHARSET=latin1;
CREATE TABLE `student` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(255) CHARACTER SET utf8 DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=25 DEFAULT CHARSET=latin1;
4,補(bǔ)充說(shuō)明
主主復(fù)制配置文件中auto_increment_increment和auto_increment_offset只能保證主鍵不重復(fù),卻不能保證主鍵有序。
當(dāng)配置完成Slave_IO_Running、Slave_SQL_Running不全為YES時(shí),show slave status\G信息中有錯(cuò)誤提示,可根據(jù)錯(cuò)誤提示進(jìn)行更正。
Slave_IO_Running、Slave_SQL_Running不全為YES時(shí),大多數(shù)問(wèn)題都是數(shù)據(jù)不統(tǒng)一導(dǎo)致。
常見(jiàn)的數(shù)據(jù)不一致情況,終極更正法:重新執(zhí)行一遍CHANGE MASTER
兩臺(tái)數(shù)據(jù)庫(kù)都存在db數(shù)據(jù)庫(kù),而第一臺(tái)MySQL db中有tab1,第二臺(tái)MySQL db中沒(méi)有tab1,那肯定不能成功。
已經(jīng)獲取了數(shù)據(jù)的二進(jìn)制日志名和位置,又進(jìn)行了數(shù)據(jù)操作,導(dǎo)致POS發(fā)生變更。在配置CHANGE MASTER時(shí)還是用到之前的POS。
stop slave后,數(shù)據(jù)變更,再start slave。出錯(cuò)。
5,參考
MySQL主從復(fù)制與主主復(fù)制
https://www.cnblogs.com/phpstudy2015-6/p/6485819.htmlMySQL 主從復(fù)制詳解(詳細(xì))
http://blog.csdn.net/u010098331/article/details/50828820