MySQL 主从搭建实现

MySQL是应用广泛的关系型数据库，当数据规模逐渐扩大，并且重要性不断提高的情况下，单数据库的可靠性和性能受到严重挑战，所以就会有了主从，读写分离等需求了。
首先在2台linux下安装mysql，最好是内网机器，可以用内网网卡做主从同步，网络质量和安全都可以得到保证。
1、安装一些常用包:
yum -y install gcc gcc-c++ autoconf libjpeg libjpeg-devel libpng libpng-devel freetype freetype-devel libxml2 libxml2-devel zlib zlib-devel glibc glibc-devel glib2 glib2-devel bzip2 bzip2-devel ncurses ncurses-devel curl curl-devel e2fsprogs e2fsprogs-devel krb5 krb5-devel libidn libidn-devel openssl openssl-devel openldap openldap-devel nss_ldap openldap-clients openldap-servers
yum -y install perl perl-URI perl-DBI perl-String newt-perl
2、下载并安装mysql
wget http://dev.mysql.com/get/Downloads/MySQL-5.5/mysql-5.5.3-m3.tar.gz/from/http://mysql.he.net/
tar -zxf mysql-5.5.3-m3.tar.gz
3、编译安装mysql
cd mysql-5.5.3-m3
./configure --prefix=/usr/local/mysql --enable-assembler --with-extra-charsets=complex --enable-thread-safe-client --with-big-tables --with-readline --with-ssl --with-embedded-server --enable-local-infile --with-plugins=partition,innobase,myisammrg &&make &&make install
4、建立mysql用户和数据文件夹等
/usr/sbin/groupadd mysql
/usr/sbin/useradd -g mysql mysql
chown -R mysql:mysql /usr/local/mysql 
mkdir -p /home/mysql/data
mkdir -p /home/mysql/binlog
mkdir -p /home/mysql/relaylog
chown -R mysql:mysql /home/mysql/*
5、初始化数据库
/usr/local/mysql/bin/mysql_install_db --basedir=/usr/local/mysql --datadir=/home/mysql/data --user=mysql
6、建立mysql启动 关闭脚本：vim /etc/init.d/mysql 如下：
#!/bin/sh   
  
 mysql_port=3306  
 mysql_username="root" //这里要修改   
 mysql_password="12345" //这里要修改   
 function_start_mysql()    
{    
     printf "Starting MySQL...\n"    
     /bin/sh /usr/local/mysql/bin/mysqld_safe --defaults-file=/home/mysql/my.cnf 2>&1 > /dev/null &    
}    
 function_stop_mysql()    
{    
     printf "Stoping MySQL...\n"    
     /usr/local/mysql/bin/mysqladmin -u ${mysql_username} -p${mysql_password} -S /tmp/mysql.sock shutdown    
}    
 function_restart_mysql()    
{    
     printf "Restarting MySQL...\n"    
      function_stop_mysql   
     sleep 5  
      function_start_mysql   
}    
 function_kill_mysql()    
{    
     kill -9 $(ps -ef |grep 'bin/mysqld_safe'| grep ${mysql_port} | awk '{printf $2}')    
     kill -9 $(ps -ef |grep 'libexec/mysqld' | grep ${mysql_port} | awk '{printf $2}')    
}    
if [ "$1" = "start" ]; then   
      function_start_mysql   
 elif [ "$1" = "stop" ]; then   
      function_stop_mysql   
 elif [ "$1" = "restart" ]; then   
      function_restart_mysql   
 elif [ "$1" = "kill" ]; then   
      function_kill_mysql   
else    
     printf "Usage: /home/mysql/mysql {start;stop;restart;kill}\n"    
 fi  
7、建立mysql配置文件：vim /home/mysql/my.cnf
主从的配置文件差异就在一个地方，主数据库这个值如下：
server-id = 1 从数据库不等于1就可以了
[client]    
 character-set-server = utf8   
 port = 3306  
socket = /tmp/mysql.sock   
  
[mysqld]    
 character-set-server = utf8   
 replicate-ignore-db = mysql   
 replicate-ignore-db = test   
 replicate-ignore-db = information_schema   
 user = mysql   
 port = 3306  
socket = /tmp/mysql.sock   
 basedir = /usr/local/mysql   
 datadir = /home/mysql/data   
log-error = /home/mysql/mysql_error.log    
 pid-file = /home/mysql/mysql.pid   
 open_files_limit = 10240  
 back_log = 600  
 max_connections = 5000  
 max_connect_errors = 6000  
 table_cache = 614  
 external-locking = FALSE    
 max_allowed_packet = 32M   
 sort_buffer_size = 1M   
 join_buffer_size = 1M   
 thread_cache_size = 300  
#thread_concurrency = 8    
 query_cache_size = 512M   
 query_cache_limit = 2M   
 query_cache_min_res_unit = 2k   
 default-storage-engine = MyISAM   
 thread_stack = 192K   
 transaction_isolation = READ-COMMITTED   
 tmp_table_size = 246M   
 max_heap_table_size = 246M   
 long_query_time = 3  
log-slave-updates   
log-bin = /home/mysql/binlog/binlog   
 binlog_cache_size = 4M   
 binlog_format = MIXED   
 max_binlog_cache_size = 8M   
 max_binlog_size = 1G   
 relay-log-index = /home/mysql/relaylog/relaylog   
 relay-log-info-file = /home/mysql/relaylog/relaylog   
 relay-log = /home/mysql/relaylog/relaylog   
 expire_logs_days = 30  
 key_buffer_size = 256M   
 read_buffer_size = 1M   
 read_rnd_buffer_size = 16M   
 bulk_insert_buffer_size = 64M   
 myisam_sort_buffer_size = 128M   
 myisam_max_sort_file_size = 10G   
 myisam_repair_threads = 1  
 myisam_recover   
 interactive_timeout = 120  
 wait_timeout = 120  
 skip-name-resolve   
#master-connect-retry = 10    
 slave-skip-errors = 1032,1062,126,1114,1146,1048,1396  
#master-host = 192.168.1.2    
#master-user = username    
#master-password = password    
#master-port = 3306    
 server-id = 1  
 innodb_additional_mem_pool_size = 16M   
 innodb_buffer_pool_size = 512M   
 innodb_data_file_path = ibdata1:256M:autoextend   
 innodb_file_io_threads = 4  
 innodb_thread_concurrency = 8  
 innodb_flush_log_at_trx_commit = 2  
 innodb_log_buffer_size = 16M   
 innodb_log_file_size = 128M   
 innodb_log_files_in_group = 3  
 innodb_max_dirty_pages_pct = 90  
 innodb_lock_wait_timeout = 120  
 innodb_file_per_table = 0  
  
#log-slow-queries = /home/mysql/slow.log   
  
#long_query_time = 10  
  
  
[mysqldump]    
 quick   
 max_allowed_packet = 32M  
8、主从都完成以上步骤，然后启动mysql：sh /etc/init.d/mysql start
9、登录主数据库就行授权
GRANT REPLICATION SLAVE ON *.* TO 'slave'@'192.168.1.2 identified by '123456';
10、查询主数据库状态，如下：
[root@test ~]# mysql -u root -p -S /tmp/mysql.sock 
Enter password: 
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3447543 to server version: 5.1.36-log
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> show master status;
+------------------+-----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+-----------+--------------+------------------+
| mysql-bin.000113 | 403767838 | | | 
+------------------+-----------+--------------+------------------+
1 row in set (0.00 sec)
11、配置从数据库
mysql> change master to master_host='192.168.1.1', master_user='slave', master_password='123456', master_log_file='mysql-bin.000113', master_log_pos=403767838;
正确执行后再执行:
mysql> start slave;
检查下运行状况：
mysql> show slave status\G
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 596
Current database: *** NONE ***
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.1
Master_User: slave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: binlog.000001
Read_Master_Log_Pos: 4120647
Relay_Log_File: relaylog.000214
Relay_Log_Pos: 248
Relay_Master_Log_File: binlog.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB: 
Replicate_Ignore_DB: mysql,test
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: 4120647
Relay_Log_Space: 538
Until_Condition: None
Until_Log_File: 
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File: 
Master_SSL_CA_Path: 
Master_SSL_Cert: 
Master_SSL_Cipher: 
Master_SSL_Key: 
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 2013
Last_IO_Error: error reconnecting to master 'slave@192.168.1.1:3306' - retry-time: 60 retries: 86400
Last_SQL_Errno: 0
Last_SQL_Error: 
1 row in set (0.00 sec)
当Slave_IO_Running: Yes和Slave_SQL_Running: Yes 都是Yes就说明正常。
12、验证是否成功
在主数据库上新建一个数据库，查看从数据库是不是也有了这个数据库；新建一张表或者插入一条记录，查看从数据库是否同步更新。
主数据库有数据的情况: 
1、数据库锁表操作，不让数据再进行写入动作。mysql> FLUSH TABLES WITH READ LOCK； 
2、察看主数据库的状态 mysql> show master status; 照前面记录输出值。
3、把主服务器数据文件复制到从服务器，最好先用压缩处理一下。
4、取消主数据库锁定 mysql> UNLOCK TABLES； 
5、从服务器的操作和之前一样。记得先stop slave 然后start slave