一、mysql的主从复制
复制过程需要至少两个mysql服务节点，mysql的主从复制框架一般都为一主多从，从多机房汇总到数据中心的模式，而复制过程只能从主服务器到从服务器实现。
复制过程中，主服务器负责读/写操作，而从服务器只负责读操作
二、主从复制的功能
1、实现数据冗余、异地灾备恢复、备份
2、实现数据的读/写分离
3、实现数据库服务的负载均衡
4、实现高可用与故障切换
5、实现MySQL的升级测试
三、主从复制过程中注意的事项
1、不要混合shi用不同的存储引擎
2、主从服务器的server-id 要保持不同
3、尽力避免修改从服务器的数据库
4、尽可能的使用基于行或基于混合模式的复制，避免使用基于语句的复制
5、主服务器要启动二进制日志，而从节点则是开启中继日志，而且要确保从服务器的复制线程时刻开启着
6、注意因为磁盘及内存的大小不足而导致的复制崩溃
四、主从复制的具体实现过程
mysql主从复制拓扑图
1、准备两个安装过mysql服务的节点xz：172.16.200.5,node2：172.16.200.7,修改主机名并同步时间；
[root@xz ~]# hostname master [root@master ~]# crontab -e */1 * * * * /usr/sbin/ntpdate 172.16.0.1 &> /dev/null [root@node2 ~]# hostname slave [root@slave ~]# crontab -e */1 * * * * /usr/sbin/ntpdate 172.16.0.1 &> /dev/null
2、在主节点上创建有复制权限的用户，于从节点上使用授权用户连接测试；
[root@master ~]# mysql Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 3 Server version: 5.5.33-log MySQL Community Server (GPL) 。。。。。 mysql> grant replication slave,replication client on *.* to 'zly'@'172.16.200.7' identified by 'mypass'; Query OK, 0 rows affected (0.35 sec) mysql> flush privileges; Query OK, 0 rows affected (0.09 sec) mysql> show grants for 'zly'@'172.16.200.7'; +-----------------------------------------------------------------------------------------------------------------------------------------------+ | Grants for [email protected] | +-----------------------------------------------------------------------------------------------------------------------------------------------+ | GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'zly'@'172.16.200.7' IDENTIFIED BY PASSWORD '*6C8989366EAF75BB670AD8EA7A7FC1176A95CEF4' | +-----------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.03 sec) ........... [root@slave ~]# mysql -uzly -pmypass -h 172.16.200.5 Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 4 Server version: 5.5.33-log MySQL Community Server (GPL) Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql>
3、修改主从两个节点的配置文件，并重新启动mysql服务;
[root@master ~]# vim /etc/my.cnf log-bin=mysql-bin log_bin_index = mysql_bin.index binlog_format=mixed server-id = 5 [root@master ~]# killall mysqld [root@master ~]# ps aux | grep mysqld root 7700 0.0 0.1 103244 832 pts/3 S+ 09:27 0:00 grep mysqld [root@master ~]# service mysqld restart MySQL server PID file could not be found! [FAILED] Starting MySQL... [ OK ] [root@master ~]# service mysqld restart Shutting down MySQL. [ OK ] Starting MySQL.. [ OK ] ............... [root@slave ~]# vim /etc/my.cnf #log-bin=mysql-bin # binary logging format - mixed recommended #binlog_format=mixed skip_slave_start = 1 read_only = 1 relay_log = relay_log relay_log_index = relay_log.index # required unique id between 1 and 2^32 - 1 # defaults to 1 if master-host is not set # but will not function as a master if omitted server-id = 7 [root@slave ~]# killall mysqld [root@slave ~]# ps aux | grep mysqld root 8796 0.0 0.1 103244 832 pts/4 S+ 23:45 0:00 grep mysqld [root@slave ~]# service mysqld restart MySQL server PID file could not be found! [FAILED] Starting MySQL.. [ OK ] [root@slave ~]# service mysqld restart Shutting down MySQL. [ OK ] Starting MySQL.. [ OK ]
4、查看主节点的二进制日志及其事件位置;
mysql> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000011 | 107 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
5、与从节点上复制主节点上的数据;
[root@slave ~]# mysql
mysql> help change master to
Name: 'CHANGE MASTER TO'
Description:
Syntax:
CHANGE MASTER TO option [, option] ...
option:
MASTER_BIND = 'interface_name'
| MASTER_HOST = 'host_name'
| MASTER_USER = 'user_name'
| MASTER_PASSWORD = 'password'
| MASTER_PORT = port_num
| MASTER_CONNECT_RETRY = interval
| MASTER_HEARTBEAT_PERIOD = interval
| MASTER_LOG_FILE = 'master_log_name'
| MASTER_LOG_POS = master_log_pos
| RELAY_LOG_FILE = 'relay_log_name'
| RELAY_LOG_POS = relay_log_pos
| MASTER_SSL = {0|1}
| MASTER_SSL_CA = 'ca_file_name'
| MASTER_SSL_CAPATH = 'ca_directory_name'
| MASTER_SSL_CERT = 'cert_file_name'
| MASTER_SSL_KEY = 'key_file_name'
| MASTER_SSL_CIPHER = 'cipher_list'
| MASTER_SSL_VERIFY_SERVER_CERT = {0|1}
| IGNORE_SERVER_IDS = (server_id_list)
server_id_list:
[server_id [, server_id] ... ]
........................................
mysql> change master to
-> master_host='172.16.200.5',master_user='zly',master_password='mypass
',master_port=3306,master_log_file='mysql-bin.000011',master_log_pos=107;
Query OK, 0 rows affected (0.07 sec)
6、启动从服务器复制线程、查看状态，并查看启动的线程;
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.200.5
Master_User: zly
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000011
Read_Master_Log_Pos: 107
Relay_Log_File: relay_log.000002
Relay_Log_Pos: 253
Relay_Master_Log_File: mysql-bin.000011
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: 107
Relay_Log_Space: 403
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
.................................
mysql> show processlist\G
*************************** 1. row ***************************
Id: 1
User: root
Host: localhost
db: NULL
Command: Query
Time: 0
State: NULL
Info: show processlist
*************************** 2. row ***************************
Id: 2
User: system user
Host:
db: NULL
Command: Connect
Time: 276
State: Waiting for master to send event
Info: NULL
*************************** 3. row ***************************
Id: 3
User: system user
Host:
db: NULL
Command: Connect
Time: 275
State: Slave has read all relay log; waiting for the slave I/O thread to update it
Info: NULL
3 rows in set (0.00 sec)
7、在主节点上创建数据库查看从节点是否已经复制;
[root@master ~]# mysql -e "create database classdb;" [root@master ~]# mysql -e "show databases;" +--------------------+ | Database | +--------------------+ | information_schema | | classdb | | mysql | | performance_schema | | testdb | +--------------------+ [root@slave ~]# mysql -e "show databases;" +--------------------+ | Database | +--------------------+ | information_schema | | classdb | | mysql | | performance_schema | +--------------------+
8、与主从节点查看已经更新的状态及二进制日志位置
[root@master ~]# mysql -e "show master status;"
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000011 | 453 | | |
+------------------+----------+--------------+------------------+
[root@slave ~]# mysql -e "show slave status\G"
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.200.5
Master_User: zly
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000011
Read_Master_Log_Pos: 453
Relay_Log_File: relay_log.000002
Relay_Log_Pos: 599
Relay_Master_Log_File: mysql-bin.000011
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
至此mysql的主从复制已经完成
五、mysql的半同步复制的具体实现
半同步复制：主服务器只要收到从服务器中的一台的返回信息，就会提交，否则需等待直至达到超时时间然后切换成异步再提交。可以使主从服务器的数据库数据的延迟较小，可以在损失很小的性能的前提下提高数据的安全性。
要进行半同步复制，只需要在主从服务器上安装上半同步复制的插件，并开启半同步复制功能，便可以进行主从复制了。
1、查看主从节点上的半同步插件，并安装插件；
[root@master ~]# cd /usr/local/mysql/lib/plugin/ [root@master plugin]# ls adt_null.so debug qa_auth_server.so auth.so libdaemon_example.so semisync_master.so auth_socket.so mypluglib.so semisync_slave.so auth_test_plugin.so qa_auth_client.so daemon_example.ini qa_auth_interface.so .................... [root@slave ~]# cd /usr/local/mysql/lib/plugin/ [root@slave plugin]# ls adt_null.so debug qa_auth_server.so auth.so libdaemon_example.so semisync_master.so auth_socket.so mypluglib.so semisync_slave.so auth_test_plugin.so qa_auth_client.so daemon_example.ini qa_auth_interface.so ...................... [root@master plugin]# mysql mysql> install plugin rpl_semi_sync_master soname 'semisync_master.so'; Query OK, 0 rows affected (0.03 sec) mysql> set global rpl_semi_sync_master_enabled = 1; Query OK, 0 rows affected (0.00 sec) mysql> set global rpl_semi_sync_master_timeout = 1000; Query OK, 0 rows affected (0.00 sec) .................................. [root@slave plugin]# mysql mysql> install plugin rpl_semi_sync_slave soname 'semisync_slave.so'; Query OK, 0 rows affected (0.04 sec) mysql> set global rpl_semi_sync_slave_enabled = 1 ; Query OK, 0 rows affected (0.01 sec) mysql> stop slave io_thread; Query OK, 0 rows affected (0.01 sec) mysql> start slave io_thread; Query OK, 0 rows affected (0.01 sec)
2、查看半同步开启的状态，并查看从节点的线程启动状态;
mysql> show global status like 'rpl_semi%';
+--------------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------------+-------+
| Rpl_semi_sync_master_clients | 1 |
| Rpl_semi_sync_master_net_avg_wait_time | 0 |
| Rpl_semi_sync_master_net_wait_time | 0 |
| Rpl_semi_sync_master_net_waits | 0 |
| Rpl_semi_sync_master_no_times | 0 |
| Rpl_semi_sync_master_no_tx | 0 |
| Rpl_semi_sync_master_status | ON |
| Rpl_semi_sync_master_timefunc_failures | 0 |
| Rpl_semi_sync_master_tx_avg_wait_time | 0 |
| Rpl_semi_sync_master_tx_wait_time | 0 |
| Rpl_semi_sync_master_tx_waits | 0 |
| Rpl_semi_sync_master_wait_pos_backtraverse | 0 |
| Rpl_semi_sync_master_wait_sessions | 0 |
| Rpl_semi_sync_master_yes_tx | 0 |
+--------------------------------------------+-------+
14 rows in set (0.00 sec)
mysql> show global variables like '%rpl%';
+------------------------------------+-------+
| Variable_name | Value |
+------------------------------------+-------+
| rpl_recovery_rank | 0 |
| rpl_semi_sync_master_enabled | ON |
| rpl_semi_sync_master_timeout | 1000 |
| rpl_semi_sync_master_trace_level | 32 |
| rpl_semi_sync_master_wait_no_slave | ON |
+------------------------------------+-------+
5 rows in set (0.00 sec)
...............
mysql> show global status like 'rpl_semi%';
+----------------------------+-------+
| Variable_name | Value |
+----------------------------+-------+
| Rpl_semi_sync_slave_status | ON |
+----------------------------+-------+
1 row in set (0.00 sec)
mysql> show global variables like '%rpl%';
+---------------------------------+-------+
| Variable_name | Value |
+---------------------------------+-------+
| rpl_recovery_rank | 0 |
| rpl_semi_sync_slave_enabled | ON |
| rpl_semi_sync_slave_trace_level | 32 |
+---------------------------------+-------+
3 rows in set (0.00 sec)
................
[root@slave ~]# mysql -e 'show slave status\G'
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.200.5
Master_User: zly
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000011
Read_Master_Log_Pos: 453
Relay_Log_File: relay_log.000003
Relay_Log_Pos: 253
Relay_Master_Log_File: mysql-bin.000011
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
3、主从双方节点都存在新建的class数据库，于主服务器上删除该数据库，然后查看从服务器是否也同步删除了;
[root@master ~]# mysql -e 'show databases;' +--------------------+ | Database | +--------------------+ | information_schema | | classdb | | mysql | | performance_schema | | testdb | +--------------------+ [root@slave ~]# mysql -e 'show databases;' +--------------------+ | Database | +--------------------+ | information_schema | | classdb | | mysql | | performance_schema | +--------------------+ 。。。。。。。。。。。。。 [root@master ~]# mysql -e 'drop database classdb;' [root@master ~]# mysql -e 'show databases;' +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | testdb | +--------------------+ [root@slave ~]# mysql -e 'show databases;' +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | +--------------------+
至此，mysql的半同步复制已经完成。