巧用mysqld_multi实现多主对一从的mysql复制

一、在两个主服务器上分别安装mysql。
useradd mysql
wget http://122.225.32.131/icons/mysql-5.0.22.tar.gz

tar -zxvf mysql-5.0.22.tar.gz

cd mysql-5.0.22

mkdir /usr/local/mysql

./configure \

--prefix=/usr/local/mysql \

--without-debug \

--enable-thread-safe-client \

--enable-assembler \

--enable-profiling \

--with-mysqld-ldflags=-all-static \

--with-client-ldflags=-all-static \

--with-charset=latin1 \

--with-extra-charsets=all \

--with-big-tables \

--enable-largefile \
make && make install

cp support-files/my-medium.cnf /etc/my.cnf
cd /usr/local/mysql/bin

./mysql_install_db --user=mysql

./mysqld_safe --user=mysql &

cp /root/mysql-5.0.22/support-files/mysql.server /etc/rc.d/init.d/mysqld

chkconfig --add mysqld

chkconfig --level 345 mysqld on

sleep 3

mysql -uroot mysql -e "delete from user where user = '';"
mysql -uroot mysql -e "grant replication slave on *.* to 'repl'@'%' identified by '123321';"
mysql -uroot mysql -e "grant shutdown on *.* to 'shutdown'@'%' identified by 'shutdown';"
//可以根据你的实际情况把%改为从服务器的IP,修改用户名和密码。
以上服务器是基本配置，如果要优化的情更具实际情况优化。

2、检查服务器配置文件，确认打开bing-log，并且配置serverid = 1
mysql
flush tables with read lock；
show master status；
+------------------+----------+--------------+------------------+

| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |

+------------------+----------+--------------+------------------+

| mysql-bin.000014 | 386037 | | |

+------------------+----------+--------------+------------------+

记录以上数值，然后通过dump，或者tar -zcvf 备份 数据库或者var目录。
unlock tables；
exit
scp 备份的var目录到从服务器上。
两个主服务器都这样操作。
3、搭建从服务器。

useradd mysql
wget http://122.225.32.131/icons/mysql-5.0.22.tar.gz

tar -zxvf mysql-5.0.22.tar.gz

cd mysql-5.0.22

mkdir /usr/local/mysql

./configure \

--prefix=/usr/local/mysql \

--without-debug \

--enable-thread-safe-client \

--enable-assembler \

--enable-profiling \

--with-mysqld-ldflags=-all-static \

--with-client-ldflags=-all-static \

--with-charset=latin1 \

--with-extra-charsets=all \

--with-big-tables \

--enable-largefile \
make && make install

cp support-files/my-medium.cnf /etc/my.cnf
修改/etc/my.cnf
在结果加上以下代码
[mysqld_multi]

mysqld = /usr/local/mysql/bin/mysqld_safe

mysqladmin = /usr/local/mysql/bin/mysqladmin

user = shutdown

password = shutdown

log = /usr/local/mysql/etc/mysqld_multi.log
[mysqld1]

socket = /tmp/mysql.sock1

port = 3306

pid-file = /usr/local/mysql/var1/localhost.pid

datadir = /usr/local/mysql/var1

user = mysql

server-id = 2
[mysqld2]

socket = /tmp/mysql.sock2

port = 3307

pid-file = /usr/local/mysql/var2/localhost.pid

datadir = /usr/local/mysql/var2

user = mysql

server-id = 2

然后
mkdir /usr/local/mysql/etc
cp support-files/mysqld_multi.server /usr/sbin/mysqld_multi.server
chmod 755 /usr/sbin/mysqld_multi.server
export PATH=$PATH:/usr/sbin/:/usr/local/mysql/bin
如果想下次启动还生效，请修改/etc/profile
把刚才备份过来的var分别放到/usr/local/mysql/下面命令为var1和var2
var1和var2和/usr/local/mysql/etc的权限必须是mysql可以写。
然后启动mysql_multi.server
mysqld_multi.server start
通过netstat -tulnp 检查端口是否启动。
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 23623/mysqld

tcp 0 0 0.0.0.0:3307 0.0.0.0:* LISTEN 23733/mysqld

通过
mysql -S /tmp/mysql.sock1 //登录第一个mysql实例
mysql -S /tmp/mysql.sock2 //登录第二个mysql实例
mysqld_multi.servr stop 1 //关闭第一个mysql实例
mysqld_multi.servr stop 1-2 //关闭第一和第二个mysql实例
mysqld_multi.servr stop //关闭所有mysql实例。start同样。

下面就是分别登录到实例1和实例2后配置mysql复制的从服务器就可以了。
mysql -S /tmp/mysql.sock1
change master to
master_host='第一个主服务器ip'，
master_user=‘repl’，
master_password='123321',
master_log_file='mysql-bin.000014‘, \\刚才show master的数据
master_log_pos=386037;
start slave;
show slave status \G;
Slave_IO_Running: Yes \\负责从主服务器读取binlog，如果为NO，应该是账号或者密码不对，不能连接到主服务器，或者是刚才的binlog号码或者pos号码有问题。请仔细检查

Slave_SQL_Running: Yes \\负责执行IO传输过来的binlog。

检查以上两项是否为yes，如果是就OK了。

另一个实例如法炮制。