17.1 MySQL主从介绍17.2 准备工作17.3 配置主17.4 配置从17.5 测试主从同步

- 17.1 MySQL主从介绍
- 17.2 准备工作
- 17.3 配置主
- 17.4 配置从
- 17.5 测试主从同步

# 17.1 MySQL主从介绍
-  MySQL主从又叫做Replication、AB复制。简单讲就是A和B两台机器做主从后，在A上写数据，另外一台B也会跟着写数据，两者数据实时同步的
-  MySQL主从是基于binlog的，主上须开启binlog才能进行主从。bilog，是二进制文件，无法cat
-  主从过程大致有3个步骤
1. 主将更改操作记录到binlog里
2. 从将主的binlog事件(sql语句)同步到从本机上并记录在relaylog里；relaylog，中继日志
3. 从根据relaylog里面的sql语句按顺序执行
-  主上有一个log dump线程，用来和从的I/O线程传递binlog
-  从上有两个线程，其中I/O线程用来同步主的binlog并生成relaylog，另外一个SQL线程用来把relaylog里面的sql语句落地
- mysql原理图

-  使用场景：
- 一、数据备份，主机器宕机，从机器还能随时对web提供服务
- 二、数据备份且可以分担主机器被调用数据时的压力，mysql主从，是有方向性的，写数据，必须从主机器开始；如果不依照原理会导致数据紊乱

# 17.2 准备工作

- 主从配置，主上操作
- mysql安装总结
- 进入src专用的下载目录下，下载mysql二进制免编译包
- wget 5.6版本，x64位
- 解压
- tar zxvf 。。。
- 移动
- mv 。。 /usr/local/mysql
- 移动时，需注意这个目录是否已经存在，如果存在了，需要删除旧文件
- 初始化配置
- 进入所在的mysql目录
```
[root@aming-01 mysql]# pwd
/usr/local/mysql
./scripts/mysql_install_db –user=mysql –datadir=/data/mysql
–user=mysql 需提前创建
```
- 编辑my.cnf文件（7版本的centos系统，就自带安装一个mariadb，所以就会自动生成有一个my.cnf，就省去了拷贝）
```
vim /etc/my.cnf   //添加以下两行内容
datadir=/data/mysql
socket=/tmp/mysql.sock
```
- 拷贝启动脚本 cp support-files/mysql.server /etc/init.d/mysqld
- 编辑启动脚本
vim /etc/init.d/mysqld //对以下两行进行指定路径
basedir=
datadir=
指定basedir的路径 /usr/local/mysql
指定datadir的路径 /data/mysql

- 最重要的一步，记得查看/data/mysql 的默认属主、属组，如果不是mysql的，启东时会因为无法写入数据而不能启动

- chomd mysql:mysql /data/mysql

- 然后就可以尝试启动
/etc/init.d/mysql start

- [x] 主机器
- 192.168.202.131
- mysql启动情况
```
[root@aming-01 ~]# ps aux |grep mysql
root        941  0.0  0.1 115392  1688 ?        S    20:14   0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/aming-01.pid
mysql      1347  1.3 45.3 1300816 452976 ?      Sl   20:14   0:02 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/data/mysql/aming-01.err --pid-file=/data/mysql/aming-01.pid --socket=/tmp/mysql.sock
root       2353  0.0  0.0 112684   980 pts/0    S+   20:17   0:00 grep --color=auto mysql
[root@aming-01 ~]#
```
- [x] 从机器
- 192.168.202.132
- mysql启动情况
```
[root@aming-02 ~]# ps aux |grep mysql
root       1074  0.0  0.1 115392  1680 ?        S    20:15   0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/data/mysql --pid-file=/data/mysql/aming-02.pid
mysql      1523  1.7 45.2 1300784 452076 ?      Sl   20:15   0:02 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/data/mysql --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/data/mysql/aming-02.err --pid-file=/data/mysql/aming-02.pid --socket=/tmp/mysql.sock
root       2284  0.0  0.0 112680   980 pts/0    S+   20:17   0:00 grep --color=auto mysql
[root@aming-02 ~]#
```

# 17.3 配置主
-  安装mysql
-  修改my.cnf，增加server-id=131和log_bin=aminglinux1
-  修改完配置文件后，启动或者重启mysqld服务
-  把mysql库备份并恢复成aming库，作为测试数据
-  mysqldump -uroot mysql > /tmp/mysql.sql
-  mysql -uroot -e “create database aming”
-  mysql -uroot aming < /tmp/mysql.sql
-  创建用作同步数据的用户
-  grant replication slave on *.* to 'repl'@slave_ip identified by 'password';
-  flush tables with read lock;
-  show master status;

- 修改主机器上的配置文件
```
[root@aming-01 ~]# vi /etc/my.cnf

[mysqld]
datadir=/data/mysql
socket=/tmp/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd 
[mysqld_safe]
#log-error=/var/log/mariadb/mariadb.log
#pid-file=/var/run/mariadb/mariadb.pid

#
# include all files from the config directory
#
#!includedir /etc/my.cnf.d

~
~
~
~
~
~
~
~
"/etc/my.cnf" 19L, 560C
```
- 更改为
```
[root@aming-01 ~]# vi /etc/my.cnf

[mysqld]
datadir=/data/mysql
socket=/tmp/mysql.sock
server-id=131
log_bin=aminglinux1
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd 
[mysqld_safe]
#log-error=/var/log/mariadb/mariadb.log
#pid-file=/var/run/mariadb/mariadb.pid

#
# include all files from the config directory
#
#!includedir /etc/my.cnf.d

~
~
~
~
~
~
:wq
```
- 修改之后要重启mysql,进入/data/mysql/目录下
```
[root@aming-01 ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL.. SUCCESS!
[root@aming-01 ~]#

[root@aming-01 ~]# pwd
/root
[root@aming-01 ~]# cd /data/mysql
[root@aming-01 mysql]# ls -lt
总用量 110768
-rw-rw----. 1 mysql mysql 50331648 11月  7 21:44 ib_logfile0
-rw-rw----. 1 mysql mysql 12582912 11月  7 21:44 ibdata1
-rw-rw----. 1 mysql mysql    29700 11月  7 21:43 aming-01.err
-rw-rw----. 1 mysql mysql        5 11月  7 21:43 aming-01.pid
-rw-rw----. 1 mysql mysql       21 11月  7 21:43 aminglinux1.index
-rw-rw----. 1 mysql mysql      120 11月  7 21:43 aminglinux1.000001
drwx------. 2 mysql mysql     4096 11月  6 22:12 zrlog
-rw-rw----. 1 mysql mysql    44847 10月 31 22:02 localhost.err
drwx------. 2 mysql mysql     4096 10月 30 23:13 mysql2
-rw-rw----. 1 mysql mysql    15630 10月 25 23:10 www.qq123.com.err
-rw-rw----. 1 mysql mysql    49405 10月 24 23:57 localhost.localdomain.err
-rw-rw----. 1 mysql mysql       56 10月 14 20:44 auto.cnf
drwx------. 2 mysql mysql     4096 10月 14 20:31 mysql
drwx------. 2 mysql mysql     4096 10月 14 20:31 performance_schema
-rw-rw----. 1 mysql mysql 50331648 10月 14 20:31 ib_logfile1
drwx------. 2 mysql mysql        6 10月 14 20:31 test
[root@aming-01 mysql]#

```
- .index  索引页，这个文件是必须要有的
- .000001 这个是二进制日志文件，会持续生成2、3、4等等（这个文件是实现主从配置的根本，没有这个文件根本没有办法实现）
- 第二步，准备一个数据，做演示用的，重新来搞一个数据出来，在blog基础上备份一个出来
```
[root@aming-01 mysql]# ls -lt
总用量 110768
-rw-rw----. 1 mysql mysql 50331648 11月  7 21:44 ib_logfile0
-rw-rw----. 1 mysql mysql 12582912 11月  7 21:44 ibdata1
-rw-rw----. 1 mysql mysql    29700 11月  7 21:43 aming-01.err
-rw-rw----. 1 mysql mysql        5 11月  7 21:43 aming-01.pid
-rw-rw----. 1 mysql mysql       21 11月  7 21:43 aminglinux1.index
-rw-rw----. 1 mysql mysql      120 11月  7 21:43 aminglinux1.000001
drwx------. 2 mysql mysql     4096 11月  6 22:12 zrlog
-rw-rw----. 1 mysql mysql    44847 10月 31 22:02 localhost.err
drwx------. 2 mysql mysql     4096 10月 30 23:13 mysql2
-rw-rw----. 1 mysql mysql    15630 10月 25 23:10 www.qq123.com.err
-rw-rw----. 1 mysql mysql    49405 10月 24 23:57 localhost.localdomain.err
-rw-rw----. 1 mysql mysql       56 10月 14 20:44 auto.cnf
drwx------. 2 mysql mysql     4096 10月 14 20:31 mysql
drwx------. 2 mysql mysql     4096 10月 14 20:31 performance_schema
-rw-rw----. 1 mysql mysql 50331648 10月 14 20:31 ib_logfile1
drwx------. 2 mysql mysql        6 10月 14 20:31 test
[root@aming-01 mysql]# mysqldump -uroot -paminglinux zrlog > /tmp/zrlog.sql
Warning: Using a password on the command line interface can be insecure.
[root@aming-01 mysql]#
[root@aming-01 mysql]# du -sh /tmp/zrlog.sql
12K	/tmp/zrlog.sql
[root@aming-01 mysql]#
```
- 新创建一个库,叫aming的库
```
[root@aming-01 mysql]# mysql -uroot -paminglinux -e "create database aming"
Warning: Using a password on the command line interface can be insecure.
[root@aming-01 mysql]#
```
- 创建库之后还需要把这个数据恢复一下
```
[root@aming-01 mysql]# mysql -uroot -paminglinux aming < /tmp/zrlog.sql
Warning: Using a password on the command line interface can be insecure.
[root@aming-01 mysql]#
```
- 现在要做的主从，参考的对象就是这个库 aming这个库
```
[root@aming-01 mysql]# ls -lt
总用量 225468
-rw-rw----. 1 mysql mysql 50331648 11月  7 21:56 ib_logfile0
-rw-rw----. 1 mysql mysql 79691776 11月  7 21:56 ibdata1
-rw-rw----. 1 mysql mysql    10543 11月  7 21:56 aminglinux1.000001
drwx------. 2 mysql mysql     4096 11月  7 21:56 aming
-rw-rw----. 1 mysql mysql    29700 11月  7 21:43 aming-01.err
-rw-rw----. 1 mysql mysql        5 11月  7 21:43 aming-01.pid
-rw-rw----. 1 mysql mysql       21 11月  7 21:43 aminglinux1.index
drwx------. 2 mysql mysql     4096 11月  6 22:12 zrlog
-rw-rw----. 1 mysql mysql    44847 10月 31 22:02 localhost.err
drwx------. 2 mysql mysql     4096 10月 30 23:13 mysql2
-rw-rw----. 1 mysql mysql    15630 10月 25 23:10 www.qq123.com.err
-rw-rw----. 1 mysql mysql    49405 10月 24 23:57 localhost.localdomain.err
-rw-rw----. 1 mysql mysql       56 10月 14 20:44 auto.cnf
drwx------. 2 mysql mysql     4096 10月 14 20:31 mysql
drwx------. 2 mysql mysql     4096 10月 14 20:31 performance_schema
-rw-rw----. 1 mysql mysql 50331648 10月 14 20:31 ib_logfile1
drwx------. 2 mysql mysql        6 10月 14 20:31 test
[root@aming-01 mysql]#

```

- 先进入到mysql里面来
```
[root@aming-01 mysql]# mysql -uroot -paminglinux
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.6.36-log MySQL Community Server (GPL)

Copyright (c) 2000, 2017, 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>

```
- 创建用作同步数据的用户
```

mysql> grant replication slave on *.* to 'repl'@'192.168.202.132' identified by 'aminglinux111';
Query OK, 0 rows affected (0.00 sec)

mysql>
```
- 不要忘记给它锁上，目的是不要再让它继续写了
- 锁表的目的是不让表继续写，因为一会需要做从机器配置，需要进行一个同步，让两台机器同步，保证两台机器的数据一致，同步才不会出错
```
mysql> flush tables with read lock;
Query OK, 0 rows affected (0.00 sec)

mysql>
```
- 做一个show master status；
```
mysql> show master status;
+--------------------+----------+--------------+------------------+-------------------+
| File               | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+--------------------+----------+--------------+------------------+-------------------+
| aminglinux1.000001 |    10755 |              |                  |                   |
+--------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql>
mysql> quit
Bye
[root@aming-01 mysql]#

```
- 需要记住binlog的filename，记住file 的位置，一会儿要用到它
- 一会儿要去从机器 上 同步这些库 （高亮的为库）
```
[root@aming-01 mysql]# ls
aming               aminglinux1.index  ib_logfile1                mysql2              zrlog
aming-01.err        auto.cnf           localhost.err              performance_schema
aming-01.pid        ibdata1            localhost.localdomain.err  test
aminglinux1.000001  ib_logfile0        mysql                      www.qq123.com.err
[root@aming-01 mysql]#
[root@aming-01 mysql]# ls /tmp/zrlog.sql
/tmp/zrlog.sql
[root@aming-01 mysql]#

```
- 把这下面的库都做一个备份
```
[root@aming-01 mysql]# mysqldump -uroot -paminglinux mysql2 > /tmp/my2.sql
Warning: Using a password on the command line interface can be insecure.
[root@aming-01 mysql]# ls /tmp/*sql
/tmp/blog,sql  /tmp/blog.sql  /tmp/my2.sql  /tmp/zrlog.sql
[root@aming-01 mysql]#
```

# 17.4 配置从
-  安装mysql，已经做了
-  查看my.cnf，配置server-id=132，要求和主不一样
-  修改完配置文件后，启动或者重启mysqld服务
-  把主上aming库同步到从上
-  可以先创建aming库，然后把主上的/tmp/mysql.sql拷贝到从上，然后导入aming库
-  mysql -uroot
-  stop slave；
-  change master to master_host='', master_user='repl', master_password='', master_log_file='', master_log_pos=xx,
-  start slave;
-  还要到主上执行 unlock tables

- 进入/etc/my.cnf
```
[root@aming-02 ~]# vi /etc/my.cnf

[mysqld]
datadir=/data/mysql
socket=/tmp/mysql.sock
server-id=132
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd 
[mysqld_safe]
#log-error=/var/log/mariadb/mariadb.log
#pid-file=/var/run/mariadb/mariadb.pid

#
# include all files from the config directory
#
#!includedir /etc/my.cnf.d

~
:wq
```
- 重启服务
```
[root@aming-02 ~]# vi /etc/my.cnf
[root@aming-02 ~]# /etc/init.d/mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL.. SUCCESS!
[root@aming-02 ~]# ls /data/mysql
aming-02.err  aminglinux1.000001  auto.cnf  ib_logfile0  localhost.localdomain.err  mysql               test
aming-02.pid  aminglinux1.index   ibdata1   ib_logfile1  localhost.localdomain.pid  performance_schema
```
- 保证和主从机器上的库数据一致
把主机器上备份的数据，拷贝到从机器上，然后做一个数据恢复
```
[root@aming-02 ~]# scp 192.168.202.131:/tmp/*.sql /tmp/
root@192.168.202.131's password:
blog.sql                                                                   100%  787     0.8KB/s   00:00
my2.sql                                                                    100%  642KB 641.9KB/s   00:00
zrlog.sql                                                                  100%   10KB   9.8KB/s   00:00
[root@aming-02 ~]#

[root@aming-02 ~]# mysql -uroot
-bash: mysql: 未找到命令

```
- 未找到命令，是因为没有把mysql命令加入到$PATH环境变量里面
- 为了方便使用mysql服务，将mysql目录、mysqldump加入到环境变量里,
```
[root@aming-02 ~]# alias 'mysql=/usr/local/mysql/bin/mysql'
[root@aming-02 ~]# alias 'mysqldump=/usr/local/mysql/bin/mysqldump'
[root@aming-02 ~]#
```
- 进入mysql
```
[root@aming-02 ~]# mysql -uroot
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.36 MySQL Community Server (GPL)

Copyright (c) 2000, 2017, 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>
```
- 创建4个库
```
mysql> create database aming;
Query OK, 1 row affected (0.00 sec)

mysql> create database zrlog;
Query OK, 1 row affected (0.00 sec)

mysql> create database blog;
Query OK, 1 row affected (0.00 sec)

mysql> create database mysql2;
Query OK, 1 row affected (0.00 sec)

mysql>

mysql> quit
Bye
[root@aming-02 ~]#

```
- 做一个恢复
```
[root@aming-02 ~]# mysql -uroot zrlog < /tmp/zrlog.sql
[root@aming-02 ~]# mysql -uroot aming < /tmp/zrlog.sql
[root@aming-02 ~]# mysql -uroot mysql2 < /tmp/my2.sql
[root@aming-02 ~]# mysql -uroot blog  < /tmp/blog.sql
[root@aming-02 ~]#
```
- 对比下俩边的文件
```
从上面
[root@aming-02 ~]# ls /data/mysql
aming         aminglinux1.000001  blog         ib_logfile1                mysql               test
aming-02.err  aminglinux1.index   ibdata1      localhost.localdomain.err  mysql2              zrlog
aming-02.pid  auto.cnf            ib_logfile0  localhost.localdomain.pid  performance_schema
[root@aming-02 ~]#
主上面
[root@aming-01 mysql]# ls
aming               aminglinux1.index  ib_logfile0                mysql               www.qq123.com.err
aming-01.err        auto.cnf           ib_logfile1                mysql2              zrlog
aming-01.pid        blog               localhost.err              performance_schema
aminglinux1.000001  ibdata1            localhost.localdomain.err  test
[root@aming-01 mysql]#

```
- 下面来实现主从
- 先进入mysql
```
[root@aming-02 ~]# mysql -uroot
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.6.36 MySQL Community Server (GPL)

Copyright (c) 2000, 2017, 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.
```
- stop slave;
```
mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql>
```
-
```
mysql> change master to master_host='192.168.202.131', master_user='repl', master_password='aminglinux111', master_log_file='aminglinux1.000001',master_log_pos=10755;
Query OK, 0 rows affected, 2 warnings (0.02 sec)

mysql>

mysql> start slave;
Query OK, 0 rows affected (0.02 sec)

mysql>
```
- 这个时候怎么判定主从有没有设置成功呢
```
mysql> start slave;
Query OK, 0 rows affected (0.02 sec)

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.202.131
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: aminglinux1.000001
Read_Master_Log_Pos: 10849
Relay_Log_File: aming-02-relay-bin.000002
Relay_Log_Pos: 285
Relay_Master_Log_File: aminglinux1.000001
Slave_IO_Running: Yes
Slave_SQL_Running: No
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 1007
Last_Error: Error 'Can't create database 'blog'; database exists' on query. Default database: 'blog'. Query: 'create database blog'
Skip_Counter: 0
Exec_Master_Log_Pos: 10755
Relay_Log_Space: 555
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: NULL
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 1007
Last_SQL_Error: Error 'Can't create database 'blog'; database exists' on query. Default database: 'blog'. Query: 'create database blog'
Replicate_Ignore_Server_Ids:
Master_Server_Id: 131
Master_UUID: 69e8b25a-b0dd-11e7-997f-000c292e28f2
Master_Info_File: /data/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State:
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp: 171107 23:15:40
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)

mysql>
```
-              Slave_IO_Running: Yes     这个很重要，其中一个是NO就表示主从已经端口
Slave_SQL_Running: No       这个很重要，其中一个是NO就表示主从已经端口

- 这里Slave_SQL_Running: No，出错了，
- 解决办法
```
mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;
Query OK, 0 rows affected (0.00 sec)

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: 192.168.202.131
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: aminglinux1.000002
Read_Master_Log_Pos: 120
Relay_Log_File: aming-02-relay-bin.000007
Relay_Log_Pos: 285
Relay_Master_Log_File: aminglinux1.000002
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: 120
Relay_Log_Space: 626
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:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 131
Master_UUID: 69e8b25a-b0dd-11e7-997f-000c292e28f2
Master_Info_File: /data/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)

mysql>

```

- 恢复主机器上的表的写操作
unlock tables
```
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)

mysql>
```

- 到此，主从就算搭建完了

# 17.5 测试主从同步
- 几个配置参数
- 主服务器上
-  binlog-do-db=            //仅同步指定的库（多个库，可以用“ , ”逗号分隔）
-  binlog-ignore-db=     //忽略指定库
- 从服务器上
-  replicate_do_db=          //仅同步指定的库
-  replicate_ignore_db=     //忽略指定库
-  replicate_do_table=         //仅同步指定的库  建议用下面两条配置，请无视这条配置
-  replicate_ignore_table=    //忽略指定库    建议用下面两条配置，请无视这条配置
-  replicate_wild_do_table=   //如aming.%, 支持通配符%  指定同步靠谱的匹配  同步表    常用
-  replicate_wild_ignore_table=   //如aming.%, 支持通配符%  指定同步靠谱的匹配  忽略表    常用
- 测试
主上进入mysql
切换到aming库
```
mysql> use aming;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql>
```
- 查看表
```
mysql> show tables;
+-----------------+
| Tables_in_aming |
+-----------------+
| comment         |
| link            |
| log             |
| lognav          |
| plugin          |
| tag             |
| type            |
| user            |
| website         |
+-----------------+
9 rows in set (0.00 sec)

mysql> select count(*) user;
+------+
| user |
+------+
|    1 |
+------+
1 row in set (0.00 sec)

mysql>
```
- 再切换到从服务器上
```
mysql> use aming;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select count(*) user;
+------+
| user |
+------+
|    1 |
+------+
1 row in set (0.00 sec)

mysql>
```
- 也是一样的，数据是一致的
- 现在要把tag表做一个删除操作
```
mysql> truncate table tag;
Query OK, 0 rows affected (0.03 sec)

mysql> select count(*) tag;
+-----+
| tag |
+-----+
|   1 |
+-----+
1 row in set (0.00 sec)

mysql>
mysql> select * from tag;
Empty set (0.00 sec)

mysql>
```
- 再去从上看下
```
mysql> select count(*) tag;
+-----+
| tag |
+-----+
|   1 |
+-----+
1 row in set (0.00 sec)

mysql> select * from tag;
Empty set (0.00 sec)

mysql>
```
- 下面做一个操作，把表直接给删掉
```
mysql> show tables;
+-----------------+
| Tables_in_aming |
+-----------------+
| comment         |
| link            |
| log             |
| lognav          |
| plugin          |
| tag             |
| type            |
| user            |
| website         |
+-----------------+
9 rows in set (0.00 sec)

mysql> drop table tag;
Query OK, 0 rows affected (0.03 sec)

mysql>

```
- 再去从上看
```
mysql> select * from tag;
ERROR 1146 (42S02): Table 'aming.tag' doesn't exist
mysql>
```
- 这就是主从同步
- 再来做个删除aming库
- 先去主上
```
mysql> drop database aming;
Query OK, 8 rows affected (0.15 sec)

mysql>
```
- 再去从上看，没有aming库了
```
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| blog               |
| mysql              |
| mysql2             |
| performance_schema |
| test               |
| zrlog              |
+--------------------+
7 rows in set (0.00 sec)

mysql>
```
- [x] 因为意外在从机器上做了意外的删除，新增，更改操作，就可以可能导致“Slave_SQL_Running: NO”
- 如果出现了“Slave_SQL_Running: NO ” 需要去主上面，重新做一个“change master”的操作 比对主机器上的“master_log_pos=10755”，就可以恢复了
- 操作前需要先sotp slave
- 然后再
- change master to master_host=’192.168.133.131′, master_user=’repl’, master_password=’aminglinux’,master_log_file=’Master.000001′, master_log_pos=10911;