mycat+mysql集群:实现读写分离，分库分表

1.mycat文档：https://github.com/MyCATApache/Mycat-doc       官方网站：http://www.mycat.org.cn/ 2.mycat的优点：

• 配置简单，灵活
• 可实现读写分离
• 可利用多种规则实现分库分表
• 心跳机制，自动踢出故障机组
• 免费开源，长期维护，社区活跃

mycat的缺点：

• 主要是分片之后有一些限制，如只能2表join

3.架构图：可实现读写分离，分库分表
4.所需软件，机器配置与ip地址

名称	版本	下载地址
mysql server	mysql  Ver 14.14 Distrib 5.6.27, for Linux (x86_64)	yum源安装，yum源地址：http://dev.mysql.com/get/mysql57-community-release-el6-7.noarch.rpm
mycat	1.3.0.3	https://github.com/MyCATApache/Mycat-download/blob/master/1.3.0.3-release/Mycat-server-1.3.0.3-release-20150527095523-linux.tar.gz
keepalived		http://www.keepalived.org/download.html

机器名	ip地址	配置	用途
mycat1	192.168.2.155/192.168.10.30	4G,4C	mycat+keepalived (主)
mycat2	192.168.2.156/192.168.10.31	4G,4C	mycat+keepalived (备)
db1	192.168.10.155	8G,4C	mysql master1
db2	192.168.10.156	8G,4C	mysql master2
db3	192.168.10.157	8G,4C	mysql slave1

5.安装，配置mysql server

• 获取官方yum源：  wget http://dev.mysql.com/get/mysql57-community-release-el6-7.noarch.rpm

• 安装源：yum install mysql57-community-release-el6-7.noarch.rpm

• 默认yum安装的是5.7,我们修改yum源，下载5.6的mysql server

• 进入yum源配置文件：cd /etc/yum.repos.d/

• 找到并编辑：vim mysql-community.repo

• 找到下面这些内容：enabled=1就是可用,把[mysql56-community]段的enabled=0改为enabled=1,相应的把[mysql57-community]段的改为0，保存退出

# Enable to use MySQL 5.6                 [mysql56-community]                 name=MySQL 5.6 Community Server                 baseurl=http://repo.mysql.com/yum/mysql-5.6-community/el/6/$basearch/                 enabled=0                 gpgcheck=1                 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql                                  [mysql57-community]                 name=MySQL 5.7 Community Server                 baseurl=http://repo.mysql.com/yum/mysql-5.7-community/el/6/$basearch/                 enabled=1                 gpgcheck=1                 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-mysql

• 查找安装包（会更新源，时间几分钟，看你的网速咯）：yum list |grep mysql

• 如果顺利就会看到这一行：mysql-community-server.x86_64              5.6.27-2.el6

• 没错就是它，安装：yum install -y mysql-community-server.x86_6

• 启动（这一步会自动初始化一些内容）：service mysqld start

• 修改root密码：mysqladmin -uroot --password ‘xxxxx’

• 修改配置文件，我测试时候的配置文件：

• db1：

[mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock character_set_server = utf8
back_log=1024 max_connections = 10000 max_connect_errors = 1000 read_buffer_size = 4M query_cache_size = 64M key_buffer_size=400M max_allowed_packet=128M innodb_flush_log_at_trx_commit=0 innodb_log_file_size = 200M innodb_log_files_in_group = 3 innodb_buffer_pool_size = 2048M innodb_log_buffer_size = 16M query_cache_size = 0 #init_connect='SET autocommit=0' innodb_lock_wait_timeout = 50
# Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0
# Recommended in standard MySQL setup sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES #replication setting server-id=1 log-bin=mysql-bin relay-log=mysql-relay-bin binlog-do-db=33hao binlog-do-db=jaydb binlog-do-db=sbtest binlog-do-db=shopnc binlog-ignore-db=mysql binlog-ignore-db=performance_schema binlog-ignore-db=information_schema log-slave-updates=1 master-info-repository=table relay-log-info-repository=table relay-log-recovery=1 #for mmm setting #read_only=1 #general log general_log=1 general_log_file=/var/log/mysql/mysql-row.log #no lower_case lower_case_table_names = 1 #slow log slow_query_log=1 slow_query_log_file=/var/log/mysql/mysql-slow.log long_query_time=2 log-queries-not-using-indexes #default timestamp explicit_defaults_for_timestamp=true
[mysqld_safe] log-error=/var/log/mysql/mysqld.log pid-file=/var/run/mysqld/mysqld.pid

• db2：

[mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock character_set_server = utf8
back_log=1024 max_connections = 10000 max_connect_errors = 1000 read_buffer_size = 4M query_cache_size = 64M key_buffer_size=400M max_allowed_packet=128M innodb_flush_log_at_trx_commit=0 innodb_log_file_size = 200M innodb_log_files_in_group = 3 innodb_buffer_pool_size = 2048M innodb_log_buffer_size = 16M query_cache_size = 0 #init_connect='SET autocommit=0' innodb_lock_wait_timeout = 50
# Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0
# Recommended in standard MySQL setup sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES #replication setting server-id=2 log-bin=mysql-bin relay-log=mysql-relay-bin binlog-do-db=33hao binlog-do-db=jaydb binlog-do-db=sbtest binlog-do-db=shopnc binlog-ignore-db=mysql binlog-ignore-db=performance_schema binlog-ignore-db=information_schema log_slave_updates=1 master-info-repository=table relay-log-info-repository=table relay-log-recovery=1 #for mmm setting #read_only=1 #general log general_log=1 general_log_file=/var/log/mysql/mysql-row.log #no lower_case lower_case_table_names = 1 #slow log slow_query_log=1 slow_query_log_file=/var/log/mysql/mysql-slow.log long_query_time=2 log-queries-not-using-indexes #default timestamp explicit_defaults_for_timestamp=true
[mysqld_safe] log-error=/var/log/mysql/mysqld.log pid-file=/var/run/mysqld/mysqld.pid

• db3：  

[mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock character_set_server = utf8
back_log=1024 max_connections = 10000 max_connect_errors = 1000 read_buffer_size = 4M query_cache_size = 64M key_buffer_size=400M max_allowed_packet=128M innodb_flush_log_at_trx_commit=0 innodb_log_file_size = 200M innodb_log_files_in_group = 3 innodb_buffer_pool_size = 2048M innodb_log_buffer_size = 16M query_cache_size = 0 #init_connect='SET autocommit=0' innodb_lock_wait_timeout = 50
# Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0
# Recommended in standard MySQL setup sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES #replication setting server-id=3 #log-bin=mysql-bin relay-log=mysql-relay-bin binlog-do-db=33hao binlog-do-db=jaydb binlog-do-db=sbtest binlog-do-db=shopnc binlog-ignore-db=mysql binlog-ignore-db=performance_schema binlog-ignore-db=information_schema master-info-repository=table relay-log-info-repository=table relay-log-recovery=1 #for mmm setting #read_only=1 #general log general_log=1 general_log_file=/var/log/mysql/mysql-row.log #no lower_case lower_case_table_names = 1 #slow log slow_query_log=1 slow_query_log_file=/var/log/mysql/mysql-slow.log long_query_time=2 log-queries-not-using-indexes #default timestamp explicit_defaults_for_timestamp=true
[mysqld_safe] log-error=/var/log/mysql/mysqld.log pid-file=/var/run/mysqld/mysqld.pid

6.从最上面的架构图中可以看出，这里只有一个主主（db1,db2），一个主从（db1,db3），下面分别配置主主，主从

7.mysql主主复制配置

(1)分别编辑db1，db2配置文件，把第5步相应的内容复制到/etc/my.cnf中 (2)接下来手动同步数据 (3)mysql>FLUSH TABLES WITH READ LOCK (4)不要退出终端，另外开一个，用mysqldump工具导出所有数据库数据，到db2数据库中 (5)在db1(192.168.10.155)的mysql上授权：grant replication slave on *.* to 'repl_user'@'192.168.10.156' identified by 'repl_password'; (6)查看db1的master状态，设置从(db2机器的mysql)的时候需要

mysql> show master status;                 +------------------+----------+--------------+------------------+-------------------+                 | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |                 +------------------+----------+--------------+------------------+-------------------+                 | mysql-bin.000001 |      336 |              |                  |                   |                 +------------------+----------+--------------+------------------+-------------------+ (7)在db2中设置master参数,(master_log_file,master_log_pos,都来自上一步)                 mysql> change master to master_host='192.168.10.156', master_user='repl_user',master_password='repl_passwd',master_log_file='mysql-bin.000001',master_log_pos=336; (8)启动db2从的复制                 mysql>slave start; (9)查看从的状态                 mysql>show slave status\G;                 Slave_IO_Running: Yes                 Slave_SQL_Running: Yes                 Seconds_Behind_Master: 0                 看到这几行说明复制成功。 (10)把db1设置为db2的从                 方法同上，重复(5)-(9),只是把db1和db2，相应的IP地址互换即可，注意重复第(7)的时候master_log_file,master_log_pos是db2的master status了。

8.把db3(192.168.10.157)设置为db1的从

方法通与7步类似，重复其中的(1)-(7)步，只是把db2和192.168.10.156换成db3和192.168.10.157。

9.至此，mysql的设置全部完成。

10.下载，安装mycat

• wget https://github.com/MyCATApache/Mycat-download/blob/master/1.3.0.3-release/Mycat-server-1.3.0.3-release-20150527095523-linux.tar.gz

• tar -zxf Mycat-server-1.3.0.3-release-20150527095523-linux.tar.gz

• 解压完成就可以使用，建议把解压后的文件夹放在/opt下，并建立mycat的软连接（ln -s “解压出来的文件夹” mycat），方便以后升级，维护。

11.配置mycat/conf/schema.xml

(1)在这里，我对33hao数据库实现读写分离 (2)对sbtest数据库所有表实现，读写不分离（当然，也可以针对某一张表，这种设置应对读写实时要求很高的情况，即单表或单库读写不分离） (3)对transdb数据库的表实现分片，users表不分片（type="global"）提高join效率，orders表，用id通过mod-log规则分片（primaryKey="id" rule="mod-long"）

<?xml version="1.0"?> < !DOCTYPE mycat:schema SYSTEM "schema.dtd"> < mycat:schema xmlns:mycat="http://org.opencloudb/">
    <schema name="33hao" checkSQLschema="false" dataNode="dn1">     </schema>     <schema name="sbtest" checkSQLschema="false" dataNode="dn2">     </schema>     <schema name="jaydb" checkSQLschema="false" dataNode="dn3">     </schema>     <schema name="transdb" checkSQLschema="false">         <table name="users" primaryKey="id" type="global" dataNode="dn4,dn5,dn6" />
                <!-- random sharding using mod sharind rule -->             <table name="orders" primaryKey="id" rule="mod-long" dataNode="dn4,dn5,dn6" />     </schema>     <schema name="shopnc" checkSQLschema="false" dataNode="dn7">     </schema>     <dataNode name="dn1" dataHost="localhost1" database="33hao" />     <dataNode name="dn2" dataHost="localhost2" database="sbtest" />     <dataNode name="dn3" dataHost="localhost1" database="jaydb" />     <dataNode name="dn4" dataHost="localhost4" database="transdb" />     <dataNode name="dn5" dataHost="localhost5" database="transdb" />     <dataNode name="dn6" dataHost="localhost6" database="transdb" />     <dataNode name="dn7" dataHost="localhost1" database="shopnc" />
    <dataHost name="localhost1" maxCon="100000" minCon="10" balance="1"         writeType="0" dbType="mysql" dbDriver="native">         <heartbeat>select user()</heartbeat>         <!-- can have multi write hosts -->         <writeHost host="hostM1" url="db1:3306" user="root"             password="123456">             <!-- can have multi read hosts -->             <readHost host="hostS1" url="db3:3306" user="root" password="123456"/>             <readHost host="hostS2" url="db2:3306" user="root" password="123456"/>         </writeHost>         <writeHost host="hostM2" url="db2:3306" user="root"             password="123456">             <!-- can have multi read hosts -->         </writeHost>         <!-- <writeHost host="hostM2" url="db2:3306" user="root" password="123456"/> -->     </dataHost>     <dataHost name="localhost2" maxCon="100000" minCon="10" balance="1"         writeType="0" dbType="mysql" dbDriver="native">         <heartbeat>select user()</heartbeat>         <!-- can have multi write hosts -->         <writeHost host="hostM1" url="db1:3306" user="root"             password="123456">         </writeHost>     </dataHost>     <dataHost name="localhost4" maxCon="100000" minCon="10" balance="0"         writeType="0" dbType="mysql" dbDriver="native">         <heartbeat>select user()</heartbeat>         <!-- can have multi write hosts -->         <writeHost host="hostM1" url="db1:3306" user="root" password="123456"></writeHost>     </dataHost>     <dataHost name="localhost5" maxCon="100000" minCon="10" balance="0"         writeType="0" dbType="mysql" dbDriver="native">         <heartbeat>select user()</heartbeat>         <!-- can have multi write hosts -->         <writeHost host="hostM2" url="db2:3306" user="root" password="123456"></writeHost>     </dataHost>     <dataHost name="localhost6" maxCon="100000" minCon="10" balance="0"         writeType="0" dbType="mysql" dbDriver="native">         <heartbeat>select user()</heartbeat>         <!-- can have multi write hosts -->         <writeHost host="hostS1" url="db3:3306" user="root" password="123456"></writeHost>     </dataHost>
12.设置mycat/conf/server.xml

• 这里是针对mycat的设置，如外部访问mycat的端口，用户名，密码，mycat的数据库有哪些等

<?xml version="1.0" encoding="UTF-8"?> < !-- - - Licensed under the Apache License, Version 2.0 (the "License");         - you may not use this file except in compliance with the License. - You         may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0         - - Unless required by applicable law or agreed to in writing, software -         distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT         WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the         License for the specific language governing permissions and - limitations         under the License. --> < !DOCTYPE mycat:server SYSTEM "server.dtd"> < mycat:server xmlns:mycat="http://org.opencloudb/">         <system>         <property name="defaultSqlParser">druidparser</property>               <property name="processors">32</property>               <property name="processorExecutor">32</property>               <property name="serverPort">3306</property>               <property name="managerPort">9066</property>
        </system>         <user name="root">                 <property name="password">123456</property>                 <property name="schemas">33hao,sbtest,jaydb,transdb,shopnc</property>         </user> < /mycat:server> 13.启动mycat

• /opt/mycat/bin/mycat start

14.连接mycat

• 和连接mysql方法一样，如果连接不上，看看是否在没个节点上都授予了mycat机器通过root/123456（在schema.xml中配置的）的方式访问：
• mysql -uroot -p123456 -h127.0.0.1 -P3306

15.测试mycat

• 我开起了general_log，数据库任何操作都会被记录，依次打开三个db1 db2 db3的日志：tail -f /var/log/mysql/mysql-row.log
• 透过mycat连接数据库 mysql -uroot -p123456 -h127.0.0.1 -P3306
• 在相应的数据库中执行操作，并观察日志。
• 比如对33hao的写总是在db1上，然后replication到db2，db3，如果db1宕机，写总是在db2上，db1恢复后，db2不会被抢占写的角色。读在db2，db3上随机执行。
• 而transdb的orders表被均匀地复制到db1，db2，db3的transdb的orders表中，users则在所有mysql（这里为db1,db2,db3）中保存副本（因为在schema.xml中设置为：type="global"）。