1.mycat文檔：https://github.com/MyCATApache/Mycat-doc 官方網站：http://www.mycat.org.cn/ 2.mycat的優點：
- 配置簡單，靈活
- 可實現讀寫分離
- 可利用多種規則實現分庫分表
- 心跳機制，自動踢出故障機組
- 免費開源，長期維護，社區活躍
mycat的缺點：
- 主要是分片之后有一些限制，如只能2表join
3.架構圖：可實現讀寫分離，分庫分表 
4.所需軟件，機器配置與ip地址
| 名稱 | 版本 | 下載地址 |
| mysql server | mysql Ver 14.14 Distrib 5.6.27, for Linux (x86_64) | yum源安裝，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 |
| 機器名 | 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 (備) |
| 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.安裝，配置mysql server
- 獲取官方yum源： wget http://dev.mysql.com/get/mysql57-community-release-el6-7.noarch.rpm
- 安裝源：yum install mysql57-community-release-el6-7.noarch.rpm
- 默認yum安裝的是5.7,我們修改yum源，下載5.6的mysql server
- 進入yum源配置文件：cd /etc/yum.repos.d/
- 找到並編輯：vim mysql-community.repo
- 找到下面這些內容：enabled=1就是可用,把[mysql56-community]段的enabled=0改為enabled=1,相應的把[mysql57-community]段的改為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
- 查找安裝包（會更新源，時間幾分鍾，看你的網速咯）：yum list |grep mysql
- 如果順利就會看到這一行：mysql-community-server.x86_64 5.6.27-2.el6
- 沒錯就是它，安裝：yum install -y mysql-community-server.x86_6
- 啟動（這一步會自動初始化一些內容）：service mysqld start
- 修改root密碼：mysqladmin -uroot --password ‘xxxxx’
- 修改配置文件，我測試時候的配置文件：
- 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.從最上面的架構圖中可以看出，這里只有一個主主（db1,db2），一個主從（db1,db3），下面分別配置主主，主從
7.mysql主主復制配置
(1)分別編輯db1，db2配置文件，把第5步相應的內容復制到/etc/my.cnf中 (2)接下來手動同步數據 (3)mysql>FLUSH TABLES WITH READ LOCK (4)不要退出終端，另外開一個，用mysqldump工具導出所有數據庫數據，到db2數據庫中 (5)在db1(192.168.10.155)的mysql上授權：grant replication slave on *.* to 'repl_user'@'192.168.10.156' identified by 'repl_password'; (6)查看db1的master狀態，設置從(db2機器的mysql)的時候需要
mysql> show master status; +------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000001 | 336 | | | | +------------------+----------+--------------+------------------+-------------------+ (7)在db2中設置master參數,(master_log_file,master_log_pos,都來自上一步) 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)啟動db2從的復制 mysql>slave start; (9)查看從的狀態 mysql>show slave status\G; Slave_IO_Running: Yes Slave_SQL_Running: Yes Seconds_Behind_Master: 0 看到這幾行說明復制成功。 (10)把db1設置為db2的從 方法同上，重復(5)-(9),只是把db1和db2，相應的IP地址互換即可，注意重復第(7)的時候master_log_file,master_log_pos是db2的master status了。
8.把db3(192.168.10.157)設置為db1的從
方法通與7步類似，重復其中的(1)-(7)步，只是把db2和192.168.10.156換成db3和192.168.10.157。
9.至此，mysql的設置全部完成。
10.下載，安裝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
- 解壓完成就可以使用，建議把解壓后的文件夾放在/opt下，並建立mycat的軟連接（ln -s “解壓出來的文件夾” mycat），方便以后升級，維護。
11.配置mycat/conf/schema.xml
(1)在這里，我對33hao數據庫實現讀寫分離 (2)對sbtest數據庫所有表實現，讀寫不分離（當然，也可以針對某一張表，這種設置應對讀寫實時要求很高的情況，即單表或單庫讀寫不分離） (3)對transdb數據庫的表實現分片，users表不分片（type="global"）提高join效率，orders表，用id通過mod-log規則分片（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.設置mycat/conf/server.xml
- 這里是針對mycat的設置，如外部訪問mycat的端口，用戶名，密碼，mycat的數據庫有哪些等
<?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.啟動mycat
- /opt/mycat/bin/mycat start
14.連接mycat
- 和連接mysql方法一樣，如果連接不上，看看是否在沒個節點上都授予了mycat機器通過root/123456（在schema.xml中配置的）的方式訪問：
- mysql -uroot -p123456 -h127.0.0.1 -P3306
15.測試mycat
- 我開起了general_log，數據庫任何操作都會被記錄，依次打開三個db1 db2 db3的日志：tail -f /var/log/mysql/mysql-row.log
- 透過mycat連接數據庫 mysql -uroot -p123456 -h127.0.0.1 -P3306
- 在相應的數據庫中執行操作，並觀察日志。
- 比如對33hao的寫總是在db1上，然后replication到db2，db3，如果db1宕機，寫總是在db2上，db1恢復后，db2不會被搶占寫的角色。讀在db2，db3上隨機執行。
- 而transdb的orders表被均勻地復制到db1，db2，db3的transdb的orders表中，users則在所有mysql（這里為db1,db2,db3）中保存副本（因為在schema.xml中設置為：type="global"）。