一、先配置好两个MySQL实例并可以正常启动
1. 首先在Linux上先安装好MySQL数据库,此处省略详细的安装步骤(可以使用yum安装)
yum -y install mysqld mysql
2. 在/usr/local目录下新建目录mysqls/mysql1, mysqls/mysql2 分别作为我们的主数据和从数据库目录,新建mysqls/run作为MySQL PID存放目录,新建mysqls/log作为MySQL日志目录
mkdir -p /usr/local/mysqls/mysql1 /usr/local/mysqls/mysql2
mkdir -p /usr/local/mysqls/run /usr/local/mysqls/log
3. 复制MySQL默认的配置文件/etc/my.cnf到/usr/local/mysqls下,并复制两份分别命名为mysql1.cnf和mysql2.cnf。这两个文件将作为主从MySQL数据库的配置文件(使用这种方式,可以不影响原有MySQL配置,默认MySQL仍可正常使用)
cp /etc/my.cnf /usr/local/mysqls/mysql1.cnf
chown -R mysql:mysql
cd /usr/local/mysqls
cp mysql1.cnf mysql2.cnf
4. 修改MySQL实例配置文件,指定datadir, socket, port, log-error, pid-file的路径:
mysql1.cnf 配置如下:
[mysqld]
datadir=/usr/local/mysqls/mysql1
socket=/usr/local/mysqls/mysql1/mysql.sock
port=33061
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
#default-character-set=utf8
character-set-server=utf8
[mysqld_safe]
log-error=/usr/local/mysqls/log/mysql1.log
pid-file=/usr/local/mysqls/run/mysql1.pid
[client]
default-character-set=utf8
socket=/usr/local/mysqls/mysql1/mysql.sock
mysql2.cnf 参考上面配置,使用mysql2目录,端口号设置为33062
5. 接下来使用mysql_install_db脚本初始化这两个MySQL数据库实例(该脚本会在mysql1和mysql2目录下自动安装MySQL基本数据库 : mysql)
/usr/bin/mysql_install_db --defaults-file=/usr/local/mysqls/mysql1.cnf
/usr/bin/mysql_install_db --defaults-file=/usr/local/mysqls/mysql2.cnf
6. 为了每次方便启动实例,我们可以编写如下启动脚本,脚本中使用mysqld_safe启动MySQL实例:
start_mysql1.sh 内容如下:
#/bin/bash
no=1
exe=/usr/bin/mysqld_safe
madmin=/usr/bin/mysqladmin
base=/usr/local/mysqls
sub=mysql$no
conf=$base/$sub.cnf
socket=$base/$sub/mysql.sock
pidfile=$base/run/$sub.pid
port=3306$no
timeout=60
$exe --defaults-file=$conf 2>&1 &
while [ $timeout -gt 0 ]; do
$madmin --socket="$socket" --user=root --port=$port ping >/dev/nul 2>&1
mret=$?
if [ $mret -eq 0 ]; then
now=`date +‘%Y-%m-%d %H:%M:%S‘`
echo "[$now] Start $sub : OK"
echo "[$now] PID : `cat $pidfile`"
netstat -atulnp | grep $port
break
fi
sleep 1
let timeout=${timeout}-1
done
start_mysql1.sh 用于启动mysql1,同样我们可以类似编写start_mysql2.sh用于启动mysql2(修改no变量的值为2即可)
注:shell 脚本文件在执行前需要设置可执行权限(类似这样:chown u+x start_mysql1.sh)
7. 至此,MySQL两个实例的准备工作就做好了,我们可以尝试启动它们了(以mysql1为例)
/usr/local/mysqls/start_mysql1.sh
如果一切顺利,将出现以下结果:
二、 接下来,我们开始设置主从复制
1. 停止MySQL实例,为了方便同样编写停止脚本
stop_mysql.sh内容如下:
#/bin/bash
if [ $# -ne 1 ]; then
echo "Usage : $0 <mysql no>"
exit -1
fi
no=$1
sub=mysql$no
base=/usr/local/mysqls
pidfile=$base/run/$sub.pid
if [ ! -f "$pidfile" ]; then
echo "‘$pidfile‘ not exist, mysql server may not start"
exit -2
fi
pid=`cat $pidfile`
kill $pid
执行:stop_mysql.sh 1 即可停止mysql1, 后面参数改为2即可停止mysql2,就像下面这样:
2. 配置主数据库,开启复制功能(这里使用mysql1作为主数据库,mysql2作为从数据库)
mysql1.cnf中[mysqld]标记下面增加如下配置:
[mysqld]
...
#replication
log-bin=/usr/local/mysqls/log/mysql1-bin.log # 这是MySQL bin log的位置
server-id=1 # server id, 标识mysql
# 下面两个参数表示确保InnoDB事务数据库可以保持最大的持久性和一致性
innodb_flush_log_at_trx_commit=1
sync_binlog=1
# 额外的参数,我们可以设置置复制哪个库、哪个表,不复制哪个库、哪个表(这里不详述,具体参考MySQL官方文档)
# 例如:
# replicate-do-db=mydb
# replicate-do-table=mytable
# replicate-ignore-db=mysql
# replicate-ignore-table=user
3. 启动mysql1,mysql命令连接并添加复制账户,同时查看master状态
start_mysql1.sh
mysql -S /usr/local/msyqls/mysql1.sock -uroot -p
mysql> grant all on *.* to ‘rep‘@‘localhost‘ identified by ‘replpass‘; # 实际环境中这里根据自己需求而定
mysql> flush privileges;
mysql> show master status \G
*************************** 1. row ***************************
File: mysql1-bin.000002
Position: 1486
Binlog_Do_DB:
Binlog_Ignore_DB:
1 row in set (0.00 sec)
4. 如果主从数据库是全新搭建的(没有实际数据)可以不用备份主库到从库,否则需要导出主库数据到从库
# 设置读锁(禁止写入)
mysql> flush tables with read lock;
# 执行备份操作
/usr/bin/mysqldump -uroot -p --database mydb1, mydb2 ... > dump.sql
#解锁
mysql> unlock tables;
?
5. 配置从数据库复制参数
mysql2.cnf中mysqld标记下增加如下配置:
#replication
log-bin=/usr/local/mysqls/log/mysql2-bin.log
server-id=2
master-host=localhost # 主库地址
master-port=33061 # 主库端口号
master-user=rep # 上面所设置的复制账户
master-pass=somepass # 复制账户密码
master-connect-retry=60 # 重试连接的间隔时间
6. 启动从数据库,若主库有数据需要导入则先导入刚才的备份,接着设置复制起始位置,启动slave
start_mysql2.sh
mysql -S /usr/local/mysqls/mysql2/mysql.sock -uroot -p < dump.sql
mysql -S /usr/local/mysqls/mysql2/mysql.sock -uroot -p
mysql> change master to
-> master_log_file=mysql1-bin.000002
-> master_log_pos=1486;
mysql> start slave;
mysql> show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: localhost
Master_User: rep
Master_Port: 33061
Connect_Retry: 60
Master_Log_File: mysql1-bin.000002
Read_Master_Log_Pos: 1486
Relay_Log_File: mysql2-relay-bin.000002
Relay_Log_Pos: 252
Relay_Master_Log_File: mysql1-bin.000002
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: 106
Relay_Log_Space: 554
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: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
1 row in set (0.00 sec)
7. OK , MySQL两实例主从复制就搭建好了。
注:文中使用mysql命令时指定socket文件是必须的,亦可以类似写相应的脚本以免每次连接都需加这个参数
mysql1.sh 内容如下:
#/bin/bash
no=1
base=/usr/local/mysqls/
sub=mysql$no
socket=$base/$sub/mysql.sock
mysql -S $socket $*
mysql2.sh 则修改no的值为2