怎樣實現MYSQL主從搭建

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怎樣實現 MYSQL 主從搭建，針對這個問題，這篇文章詳細介紹了相對應的分析和解答，希望可以幫助更多想解決這個問題的小伙伴找到更簡單易行的方法。

一主單從
步驟：
1、配置 master 主機的 my.cnf，配置內容如下：

[mysqld]
user=mysql
pid-file=/var/run/mysqld/mysqld.pid
socket=/var/run/mysqld/mysqld.sock
port=3306
basedir=/usr
datadir=/var/lib/mysql
tmpdir=/tmp
log-bin=master-bin
log-bin-index=master-bin.index
server-id=1

配置完之后重啟，使 my.cnf 生效

創建復制用戶，并賦予 replication slave 權限給 slave 節點

mysql create user repl_user;

mysql grant replication slave on *.* to repl_user@mt identified by xyzzy;

2、配置 slave 從機的 my.cnf，配置內容如下：

[mysqld]
user=mysql
pid-file=/var/run/mysqld/mysqld.pid
socket=/var/run/mysqld/mysqld.sock
port=3306
basedir=/usr
datadir=/var/lib/mysql
tmpdir=/tmp
server-id=2
relay-log-index=slave-relay-bin.index
relay-log=slave-relay-bin

在 slave 上配置 slave 與 master 的連接

change master to
master_host= mo ,
master_port= 3306 ,
master_user repl_user ,
master_password= xyzzy ,
master_log_file= mysql-bin.00002 ,
master_log_pos=101;

啟動 slave
start slave

3、查看 slave 的狀態

mysql show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: mo
Master_User: repl_user
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: master-bin.000001
Read_Master_Log_Pos: 946
Relay_Log_File: slave-relay-bin.000002
Relay_Log_Pos: 1092
Relay_Master_Log_File: master-bin.000001
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: 946
Relay_Log_Space: 1247
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)

如果 Slave_IO_Running、Slave_SQL_Running 均為 yes 則證明配置成功，如果有其中一個為 no，如下所示：

mysql show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Connecting to master
Master_Host: mo
Master_User: repl_user
Master_Port: 3306
Connect_Retry: 60
Master_Log_File:
Read_Master_Log_Pos: 4
Relay_Log_File: slave-relay-bin.000001
Relay_Log_Pos: 4
Relay_Master_Log_File:
Slave_IO_Running: No
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: 0
Relay_Log_Space: 106
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: 2013
Last_IO_Error: error connecting to master repl_user@mo:3306 – retry-time: 60 retries: 86400
Last_SQL_Errno: 0
Last_SQL_Error:
1 row in set (0.00 sec)

則查看 Last_IO_Errno、Last_IO_Error 參數，和 datadir 目錄下的 hostname.err 文件找出錯誤日志信息，如下所示

[root@mt ~]# cd /var/lib/mysql/
[root@mt mysql]# ls
ibdata1 ib_logfile0 ib_logfile1 master.info mt.err mysql relay-log.info slave-relay-bin.000001 slave-relay-bin.index test
[root@mt mysql]# cd mt.err
-bash: cd: mt.err: Not a directory
[root@mt mysql]# tail -f n 200 mt.err
tail: cannot open `n for reading: No such file or directory
tail: cannot open `200 for reading: No such file or directory
== mt.err ==
160731 19:27:43 InnoDB: Initializing buffer pool, size = 8.0M
160731 19:27:43 InnoDB: Completed initialization of buffer pool
160731 19:27:43 InnoDB: Started; log sequence number 0 44233
160731 19:27:43 [Note] Event Scheduler: Loaded 0 events
160731 19:27:43 [Note] /usr/libexec/mysqld: ready for connections.
Version: 5.1.71 socket: /var/run/mysqld/mysqld.sock port: 3306 Source distribution
160731 19:47:02 [Note] CHANGE MASTER TO executed . Previous state master_host= , master_port= 3306 , master_log_file= , master_log_pos= 4 . New state master_host= mo , master_port= 3306 , master_log_file= , master_log_pos= 4 .
160731 19:47:09 [Note] Slave SQL thread initialized, starting replication in log FIRST at position 0, relay log ./slave-relay-bin.000001 position: 4
160731 19:47:09 [ERROR] Slave I/O: error connecting to master repl_user@mo:3306 – retry-time: 60 retries: 86400, Error_code: 2005
160731 21:13:09 [ERROR] Slave I/O: error connecting to master repl_user@mo:3306 – retry-time: 60 retries: 86400, Error_code: 2013
上述錯誤為 repl_user 沒有給 slave 機 replication slave 權限

可以查看 select user,host,password from mysql.user; 看到 user 在哪個 host 上可以登陸，如果 repl_user 對應的 host 沒有 slave 節點對應的主機名，則 repl_user 用戶無法在 slave 機上進行遠程連接到 master 所在的節點機。

可以使用 show binary logs 查看 logbin 的日志信息
可以使用 show master status \G 查看主節點信息

關于怎樣實現 MYSQL 主從搭建問題的解答就分享到這里了，希望以上內容可以對大家有一定的幫助，如果你還有很多疑惑沒有解開，可以關注丸趣 TV 行業資訊頻道了解更多相關知識。

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