第17章MySQL主从配置-白红宇

第17章MySQL主从配置

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发布时间：2019-06-18

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mysql安装总结

mysql主从准备工作：

准备两台机器，每台机器安装msyql服务，并启动mysql服务

mysql详细安装

1.首先下载二进制免编译的包，下载到/usr/local/src/目录下

2.解压压缩包

3.解压完之后，把解压出来的目录放到 /usr/local/mysql/ 目录下

注意点：

首先检查 /usr/local/mysql/ 目录是否存在

若是这个目录存在，首先把这个目录改个名字，或者把目录下的内容删除

然后把解压出来的目录放到 /usr/local/mysql/ 目录下面

[root@xuexi-001 ~]# ls /usr/local/mysqlbin      data  include  man     my-new.cnf  README   share      support-filesCOPYING  docs  lib      my.cnf  mysql-test  scripts  sql-bench

4.然后切换到 /usr/local/mysql/ 目录下，进行初始化命令

初始化命令 ./scripts/mysql_install_db --user=mysql --datadir=/data/mysql

注意点：

其中的--user=mysql 需要提前创建

5.初始化成功的标志就是两个OK，或者用 echo $? 检查是否初始化成功

6.编辑 /etc/my.cnf 文件——>默认是自带 my.cnf 文件的

在 /etc/my.cnf 文件中定义 datadir=/data/mysql     定义 socket=/tmp/mysql.sock

7.拷贝启动脚本

命令 cp /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld

8.编辑启动脚本

vim /etc/init.d/mysqld //对以下两行进行指定路径指定basedir的路径 /usr/local/mysql  指定datadir的路径 /data/mysql

9.之后就可以启动mysql了

命令 /etc/init.d/mysql start

10.如果启动失败，可以去查看错误日志

11.建议：

查看 /data/mysql 目录下的文件，默认属主、属组，如果不是mysql的，启动时会因无法写入数据而不能启动mysql

改变属主和属组，命令 chomd mysql:mysql /data/mysql

然后就可以尝试启动，命令 /etc/init.d/mysql start

12.若想开机启动，只需要输入命令

命令 chkconfig mysqld on

配置主

主从配置 - 主上操作

安装mysql

修改my.cnf，增加server-id=130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;

主从配置 - 主上操作

1.在两台机器安装并启动mysql服务后，首先在主上进行操作

2.修改/etc/my.cnf配置文件

在配置文件下[mysqld]下添加

server_id=130 这个id可以自定义，这里根据ip来定义

log_bin=xuexi1打开binlog，名字自定义为log_bin=xuexi1 最终如下

[root@xuexi-001 ~]# vim /etc/my.cnf# For advice on how to change settings please see# http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html# *** DO NOT EDIT THIS FILE. It's a template which will be copied to the# *** default location during install, and will be replaced if you# *** upgrade to a newer version of MySQL.[mysqld]server_id = 130log_bin=xuexi1# Remove leading # and set to the amount of RAM for the most important data# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.# innodb_buffer_pool_size = 128M# Remove leading # to turn on a very important data integrity option: logging# changes to the binary log between backups.# log_bin# These are commonly set, remove the # and set as required.# basedir = .....# datadir = .....# port = .....# server_id = .....# socket = .....# Remove leading # to set options mainly useful for reporting servers.# The server defaults are faster for transactions and fast SELECTs.# Adjust sizes as needed, experiment to find the optimal values.# join_buffer_size = 128M# sort_buffer_size = 2M# read_rnd_buffer_size = 2M 保存退出

3.更改完配置文件后，需要重启mysql /etc/init.d/mysqld restart

[root@xuexi-001 ~]# /etc/init.d/mysqld restartShutting down MySQL.... SUCCESS! Starting MySQL.. SUCCESS!

4.这时候来/data/mysql/目录下，会生成一些文件

ls -lt /data/mysql/

[root@xuexi-001 ~]# cd /data/mysql/[root@xuexi-001 mysql]# ls -lt总用量 110944-rw-rw---- 1 mysql mysql 50331648 8月  31 22:57 ib_logfile0-rw-rw---- 1 mysql mysql 12582912 8月  31 22:57 ibdata1-rw-rw---- 1 mysql mysql   276358 8月  31 22:57 xuexi-001.err-rw-rw---- 1 mysql mysql        5 8月  31 22:57 xuexi-001.pid-rw-rw---- 1 mysql mysql       32 8月  31 22:57 xuexi1.index-rw-rw---- 1 mysql mysql      120 8月  31 22:57 xuexi1.000002-rw-rw---- 1 mysql mysql      143 8月  31 22:57 xuexi1.000001drwx------ 2 mysql mysql      324 8月  30 07:56 zrlogdrwx------ 2 mysql mysql     4096 7月  25 22:21 mysql2drwx------ 2 mysql mysql       48 7月  23 00:12 db1-rw-rw---- 1 mysql mysql       56 7月   3 23:41 auto.cnfdrwx------ 2 mysql mysql     4096 7月   3 23:33 mysqldrwx------ 2 mysql mysql     4096 7月   3 23:33 performance_schema-rw-rw---- 1 mysql mysql 50331648 7月   3 23:33 ib_logfile1drwx------ 2 mysql mysql        6 7月   3 23:33 test

其中 .index 索引页，这个文件是必须要有的

其中 .000001

5.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完成主从）

6.测试，准备一个数据做演示用的首先做一个备份

mysqldump -uroot -p123456 zrlog > /tmp/zrlog.sql

[root@xuexi-001 ~]# mysqldump -uroot -phanfeng zrlog > /tmp/zrlog.sqlWarning: Using a password on the command line interface can be insecure.

7.然后创建一个新的库

mysql -uroot -p123456 -e "create database xuexi"

[root@xuexi-001 mysql]# mysql -uroot -p123456 -e "create database xuexi"Warning: Using a password on the command line interface can be insecure.

8.创建好库后，还需要把数据恢复一下，那也就是说做的主从，参考的对象就是 xuexi 这个库

mysql -uroot -p123456 xuexi < /tmp/zrlog.sql

[root@xuexi-001 mysql]# mysql -uroot -p123456 xuexi < /tmp/zrlog.sql Warning: Using a password on the command line interface can be insecure.

9.再来查看/data/mysql/目录下的文件 ls -lt /data/mysql/

[root@xuexi-001 mysql]# ls -lt /data/mysql/总用量 225592-rw-rw---- 1 mysql mysql 50331648 8月  31 23:16 ib_logfile0-rw-rw---- 1 mysql mysql 79691776 8月  31 23:16 ibdata1-rw-rw---- 1 mysql mysql    10348 8月  31 23:16 xuexi1.000002drwx------ 2 mysql mysql      324 8月  31 23:16 xuexi-rw-rw---- 1 mysql mysql   276358 8月  31 22:57 xuexi-001.err-rw-rw---- 1 mysql mysql        5 8月  31 22:57 xuexi-001.pid-rw-rw---- 1 mysql mysql       32 8月  31 22:57 xuexi1.index-rw-rw---- 1 mysql mysql      143 8月  31 22:57 xuexi1.000001drwx------ 2 mysql mysql      324 8月  30 07:56 zrlogdrwx------ 2 mysql mysql     4096 7月  25 22:21 mysql2drwx------ 2 mysql mysql       48 7月  23 00:12 db1-rw-rw---- 1 mysql mysql       56 7月   3 23:41 auto.cnfdrwx------ 2 mysql mysql     4096 7月   3 23:33 mysqldrwx------ 2 mysql mysql     4096 7月   3 23:33 performance_schema-rw-rw---- 1 mysql mysql 50331648 7月   3 23:33 ib_logfile1drwx------ 2 mysql mysql        6 7月   3 23:33 test

10.能看到xuexi1.000002二进制文件是有增加的，xuexi1.000002增长的大小是和zrlog这个库的保持一致的，xuexi1.000002文件里完整的记录了数据库的创建的库，创建的表，以及表里的内容全都有

11.下面创建用于主从相互同步数据的用户

12.先进入到mysql里面去

mysql -uroot -p123456

[root@xuexi-001 mysql]# mysql -uroot -p123456Warning: 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 4Server 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 itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql>

13.创建用户

grant replication slave on . to 'repl'@'192.168.5.130' identified by '234567';

指定权限，replication slave权限

针对repl这个用户

针对从的那个IP，指定来源（若是写所有的IP会很危险）

mysql> grant replication slave on *.* to 'repl'@'192.168.5.133' identified by '234567';Query OK, 0 rows affected (0.00 sec)mysql>

14.锁定表，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

flush tables with read lock;

mysql> flush tables with read lock;Query OK, 0 rows affected (0.00 sec)mysql>

15.查看一下binlog的文件和大小，并记住binlog的filename

show master status;

mysql> show master status;+---------------+----------+--------------+------------------+-------------------+| File          | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |+---------------+----------+--------------+------------------+-------------------+| xuexi1.000002 |    10558 |              |                  |                   |+---------------+----------+--------------+------------------+-------------------+1 row in set (0.00 sec)

16.然后退出数据库，做一个数据同步

17.查看/data/mysql/下有哪些库，主上有哪些库，一会从上也得有哪些库，同步这些库，就意味着这些数据都得备份过去

[root@xuexi-001 mysql]# ls auto.cnf     ib_logfile1         test           xuexi1.000001db1          mysql               xuexi          xuexi1.000002ibdata1      mysql2              xuexi-001.err  xuexi1.indexib_logfile0  performance_schema  xuexi-001.pid  zrlog

18.备份数据库，除了mysql库，因为mysql库里面有账号密码，从上的时候不可能把所有权限复制过去，所以mysql不需要备份

备份其他的库

[root@xuexi-001 mysql]# mysqldump -uroot -p123456 test > /tmp/test.sqlWarning: Using a password on the command line interface can be insecure.[root@xuexi-001 mysql]# mysqldump -uroot -p123456 mysql2 > /tmp/mysql2.sqlWarning: Using a password on the command line interface can be insecure.

19.等会把/tmp/目录下 .sql文件都拷贝到从上去

[root@xuexi-001 mysql]# ls /tmp/*.sql/tmp/mysql2.sql  /tmp/test.sql  /tmp/zrlog.sql

20.主上操作完成，接下来从上操作

配置从

主从配置 - 从上操作

安装mysql

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

主从配置 - 从上操作

在从上机器配置

1.首先在从上安装并启动mysql，然后查看my.cnf，配置server_id=133，要求和主不一样，在配置文件的 log_bin参数就不需要配置的，因为只有主上才需要二进制日志文件

[root@xuexi-001 ~]# vim /etc/my.cnf[mysqld]datadir=/data/mysqlsocket=/tmp/mysql.sockserver-id=133# Disabling symbolic-links is recommended to prevent assorted security riskssymbolic-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.djoin_buffer_size = 128Msort_buffer_size = 2Mread_rnd_buffer_size = 2M保存退出

2.重启mysql服务

[root@xuexi-001 ~]#  /etc/init.d/mysqld restartShutting down MySQL.... SUCCESS! Starting MySQL... SUCCESS!

3.在增加 server-id 后，对于mysql 是没有任何变化的

[root@localhost ~]# ls /data/mysql/auto.cnf     ib_logfile1                mysqlibdata1      localhost.localdomain.err  performance_schemaib_logfile0  localhost.localdomain.pid  test

4.把主机器上备份的 .sql 数据，拷贝到从机器上，然后做一个数据恢复

scp 192.168.202.130:/tmp/*.sql /tmp/

拷贝数据失败

原因：

在拷贝的数据的时候，一直拷贝数据失败，因为在主上的机器里有开机启动脚本，所以导致拷贝数据失败

[root@localhost ~]# scp 192.168.5.130:/tmp/*.sql /tmp/The authenticity of host '192.168.5.130 (192.168.5.130)' can't be established.ECDSA key fingerprint is SHA256:VuRutO7q299bCFi40MmwIrojehhw6Uv2Z6Wm+QYfp6Q.ECDSA key fingerprint is MD5:80:f0:db:83:55:d0:a5:6b:d8:e6:9a:22:bc:e6:2b:49.Are you sure you want to continue connecting (yes/no)? yPlease type 'yes' or 'no': yesWarning: Permanently added '192.168.5.130' (ECDSA) to the list of known hosts.root@192.168.5.130's password: mysql2.sql                    100%  643KB  12.6MB/s   00:00    test.sql                      100% 1258   236.9KB/s   00:00    zrlog.sql                     100% 9869   770.5KB/s   00:00

解决方法：
- 将主机器的里的开机启动脚本关闭vi .bashrc配置文件文件中注释掉脚本，再来拷贝数据到从机器上，会发现成功

[root@xuexi-001 ~]# scp 192.168.5.130:/tmp/*.sql /tmp/The authenticity of host '192.168.5.130 (192.168.5.130)' can't be established.ECDSA key fingerprint is 25:ce:a9:96:36:88:84:ab:4f:7e:80:a3:e7:36:2c:9f.Are you sure you want to continue connecting (yes/no)? yes\Warning: Permanently added '192.168.202.130' (ECDSA) to the list of known hosts.root@192.168.5.130's password: test.sql                                                      100% 1258     1.2KB/s   00:00    zrlog.sql                                                     100%   10KB   9.8KB/s   00:00

5.进入到从上数据库中——>因为从上没设置密码，所以可以直接进去

[root@xuexi-001 ~]# mysql -uroot-bash: mysql: 未找到命令

mysql -uroot命令不存在，是因为没有加入到PATH里面

这里做个alias别名设置，用单引号' '

[root@xuexi-001 ~]# alias 'mysql=/usr/local/mysql/bin/mysql'[root@xuexi-001 ~]# alias 'mysqldump=/usr/local/mysql/bin/mysqldump'

这时候就可以进入到mysql里面去了

[root@xuexi-001 ~]# mysql -urootWelcome to the MySQL monitor.  Commands end with ; or \g.Your MySQL connection id is 1Server version: 5.6.35 MySQL Community Server (GPL)Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql>

6.创建库

create database zrlog;

create database test1;

create database mysql2;

mysql> create database zrlog;Query OK, 1 row affected (0.00 sec)mysql> create database test1;Query OK, 1 row affected (0.00 sec)mysql> create database mysql2;Query OK, 1 row affected (0.00 sec)mysql> quitBye退出数据库

7.然后将数据库做一个恢复

mysql -uroot test1 < /tmp/test.sql

mysql -uroot zrlog < /tmp/zrlog.sql

mysql -uroot mysql2 < /tmp/mysql2.sql

[root@localhost ~]# mysql -uroot test1 < /tmp/test.sql[root@localhost ~]# mysql -uroot zrlog < /tmp/zrlog.sql[root@localhost ~]# mysql -uroot mysql2 < /tmp/mysql2.sql

保证两边数据一致

然后查看/data/mysql/目录下的数据是否和主机器上的/data/mysql/目录是否一致

8.开始实现主从

9.在从机器登录到mysql

[root@xuexi-001 ~]# mysql -urootWelcome to the MySQL monitor.  Commands end with ; or \g.Your MySQL connection id is 6Server version: 5.6.35 MySQL Community Server (GPL)Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql>

10.然后在数据库里面执行命令，停止slave

stop slave;

mysql> stop slave;Query OK, 0 rows affected, 1 warning (0.00 sec)mysql>

11.配置主机器相关配置

change master to master_host='192.168.5.130', master_user='repl', master_password='234567', master_log_file='xuexi1.000002', master_log_pos=10558;

master_host='192.168.202.130'，指定主机器host

master_user='repl'，指定主机器用户

master_password='hanfeng'，指定主机器密码

master_log_file='hanfeng1.000001'，指定binlog文件名

master_log_pos=10549，指定binlog文件大小

也可以指定主机器的port，因为在生产环境中，也会有人更改mysql的默认端口 master_port=3306

mysql> change master to master_host='192.168.5.130', master_user='repl', master_password='234567', master_log_file='xuexi1.000002', master_log_pos=10558;Query OK, 0 rows affected, 2 warnings (0.01 sec)

12.开始slave

start slave;

mysql> start slave;Query OK, 0 rows affected (0.01 sec)mysql>

13.这时候通过 show slave status\G 判断主从是否配置成功

查看slave配置

show slave status\G

在G后面不需要加分号，\G本身就是一种结束符

看 Slave_IO_Running: Yes 是否为yes

看 Slave_SQL_Running: Yes 是否为yes

mysql> show slave status\G*************************** 1. row ***************************               Slave_IO_State: Waiting for master to send event                  Master_Host: 192.168.5.130                  Master_User: repl                  Master_Port: 3306                Connect_Retry: 60              Master_Log_File: xuexi1.000004          Read_Master_Log_Pos: 120               Relay_Log_File: localhost-relay-bin.000005                Relay_Log_Pos: 280        Relay_Master_Log_File: xuexi1.000004             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: 617              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: 0Master_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: 130                  Master_UUID: 9bace481-7ed7-11e8-98a4-000c29b3a2bf             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: 01 row in set (0.00 sec)mysql>

14.解锁“主”上的表（在主上机器操作）

unlock tables;

[root@xuexi-001 ~]# mysql -uroot -p123456Warning: 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 2Server 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 itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql> unlock tables;Query OK, 0 rows affected (0.00 sec)

15.到这里主从搭建就算完成了

查看主从同步是否正常

从上执行mysql -uroot

show slave stauts\G

看是否有

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

还需关注

Seconds_Behind_Master: 0 //为主从延迟的时间

Last_IO_Errno: 0

Last_IO_Error:

Last_SQL_Errno: 0

Last_SQL_Error:

测试主从同步

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）——>英文的逗号 ， 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=         //仅同步指定的表replicate_ignore_table=    //忽略指定表，    - 例如：有一个临时表，写的数据非常快，数据也大，每天都需要删除这时就可以更新删除这个，那么就不需要每天去做同步 replicate_wild_do_table=   //如aming.%, 支持通配符%  指定同步靠谱的匹配  同步表   replicate_wild_ignore_table=   //如aming.%, 支持通配符%  指定同步靠谱的匹配  忽略表

进行从服务器的配置时尽量使用参数“replicate_wild_”，使匹配更精确，提升使用性能。

测试主从

主上 mysql -uroot aming

select count(*) from db;

truncate table db;

到从上 mysql -uroot aming

select count(*) from db;

主上继续drop table db;

从上查看db表

1.在主上机器，进入到mysql

[root@xuexi-001 ~]# mysql -uroot -p123456Warning: 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 5562Server version: 5.6.35-log MySQL Community Server (GPL)Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql>

2.进入到zrlog库里面

mysql> use zrlog;Reading table information for completion of table and column namesYou can turn off this feature to get a quicker startup with -ADatabase changedmysql>

3.查看表，有几个表

show tables;mysql> show tables;+-----------------+| Tables_in_zrlog |+-----------------+| comment         || link            || log             || lognav          || plugin          || tag             || type            || user            || website         |+-----------------+9 rows in set (0.00 sec)mysql>

4.查看表有多少行，会看到website里面有9行数据

select count(*) from website;

mysql> select count(*) from website;+----------+| count(*) |+----------+|        9 |+----------+1 row in set (0.00 sec)mysql>

5.这时候再来查看从上的zrlog表上的数据，会看到是一样的

6.将主机器上的表做一个删除操作

truncate table website;

truncate 表示清空

mysql> truncate table website;Query OK, 0 rows affected (0.04 sec)

7.再来查看主机器的表和从机器上表都会被删除了

主

mysql> select count(*) from website;+----------+| count(*) |+----------+|        0 |+----------+1 row in set (0.00 sec)

从

mysql> select count(*) from website;+----------+| count(*) |+----------+|        0 |+----------+1 row in set (0.00 sec)

若是误操作了，比如在从机器误删除了，再去主上删除相同的数据，就会有可能导致主从失败

这时在从机器上 start slave;

然后在start slave;

再来查看show slave status\G

若是还是失败，则只能重新做主从了

重新主从

在主机器的数据库上 show mater status; 查看文件大小

然后在从机器上先stop slave;

然后直接change master to master_host='192.168.202.130', master_user='repl', master_password='hanfeng', master_log_file='hf123.000001', master_log_pos=10549;