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Mysql 主從數(shù)據(jù)庫同步(centos篇)

更新時(shí)間：2011年05月26日 01:12:02 作者：

Mysql 主從數(shù)據(jù)庫同步(centos篇)，需要的朋友可以參考下。

環(huán)境:

主服務(wù)器:centos 5.2 mysql 5.1.35 源碼 IP:192.168.1.22

從服務(wù)器:centos 5.2 mysql 5.1.35 源碼 IP:192.168.1.33

配置:

一、主服務(wù)器

1.1、創(chuàng)建一個(gè)復(fù)制用戶，具有replication slave 權(quán)限。

mysql>grant replication slave on *.* to 'repl'@'192.168.1.22' identified by 'repl';

1.2、編輯my.cnf文件

vi /etc/my.cnf
添加
server-id=1
并開啟log-bin二進(jìn)制日志文件
log-bin=mysql-bin

注:需要把默認(rèn)的server-id=1去掉

1.3、啟動(dòng)mysql數(shù)據(jù)庫

mysqld_safe --user=mysql &

1.4、設(shè)置讀鎖

mysql>flush tables with read lock;

1.5、得到binlog日志文件名和偏移量

mysql>show master status;

+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.0000010 | 106| | |
+------------------+----------+--------------+------------------+

1.6、備份要同步的數(shù)據(jù)庫

mysqldump test > test.sql

1.7、解鎖

mysql>unlock tables;

二、從服務(wù)器

2.1、編輯my.cnf文件

vi /etc/my.cnf
添加
server-id=2

注:需要把默認(rèn)的server-id=1去掉

2.2、啟動(dòng)從數(shù)據(jù)庫

mysqld_safe --user=mysql &

2.3、對(duì)從數(shù)據(jù)庫進(jìn)行相應(yīng)設(shè)置

mysql> change master to
        -> master_host='192.168.1.22'
        -> master_user='repl'
        -> master_password='repl'
        -> master_log_file='mysql-bin.0000010'
        -> master_log_pos=106;

2.4、啟動(dòng)從服務(wù)器slave線程

mysql>start slave;

執(zhí)行show processlist命令顯示以下進(jìn)程:

mysql>show processlist\G
*************************** 2. row ***************************
         Id: 2
     User: system user
     Host:
         db: NULL
Command: Connect
     Time: 2579
    State: Has read all relay log; waiting for the slave I/O thread to update it
     Info: NULL

表示slave已經(jīng)連接上master，開始接受并執(zhí)行日志

2.5、查看slave線程狀態(tài)

mysql>show slave status;

*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.22

                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.0000010
          Read_Master_Log_Pos: 106
               Relay_Log_File: centos-relay-bin.000002
                Relay_Log_Pos: 529
        Relay_Master_Log_File: mysql-bin.0000010
             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: 830
              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)

驗(yàn)證是否配置正確

在從服務(wù)器上執(zhí)行

show slave status\G;
Waiting for master to send event
Slave_IO_Running: Yes
Slave_SQL_Running: Yes

如以上二行同時(shí)為Yes 說明配置成功

測(cè)試

1、在主服務(wù)器test數(shù)據(jù)庫中創(chuàng)建user表

mysql>use test;
mysql>create table user(id int);

2、在從服務(wù)器中查看user表

mysql>use test;
mysql> show tables like 'user';
+----------------------+
| Tables_in_test(user) |
+----------------------+
| user |
+----------------------+
1 row in set (0.00 sec)

說明主從數(shù)據(jù)同步成功。

問題?

1.在從數(shù)據(jù)庫中查看slave狀態(tài)時(shí)出現(xiàn)

The slave I/O thread stops because master and slave have equal MySQL server ids; these ids must be different for replication to work (or the --replicate-same-server-id option must be used on slave but this does not always make sense; please check the manual before using it)

說明方從服務(wù)器里my.cnf中的server-id有相同的。

解決辦法:

修改my.cnf里的server-id，并重啟數(shù)據(jù)庫服務(wù)。my.cnf文件默認(rèn)有server-id=1

其它說明

主服務(wù)器my.cnf

#binlog-do-db=需要備份的數(shù)據(jù)庫名，可寫多行
#binlog-ignore-db=不需要備份的數(shù)據(jù)庫名，可寫多行
從服務(wù)器my.cnf

# replicate-do-db=test 需要備份的數(shù)據(jù)庫名
# replicate-ignore-db=mysql 忽略的數(shù)據(jù)庫
# master-connect-retry=60 如果從服務(wù)器發(fā)現(xiàn)主服務(wù)器斷掉，重新連接的時(shí)間差(秒)

以下設(shè)置也可直接修改my.cnf配置文件

log-bin=mysql-bin
master-host=192.168.1.22

master-user=repl

master-password=repl
master-port=3306

主從服務(wù)器同步維護(hù)

由于各種原因，導(dǎo)致主從數(shù)據(jù)不一致，在負(fù)載低的時(shí)候，進(jìn)行手動(dòng)同步.

在主服務(wù)器上執(zhí)行

mysql>flush tables with read lock;

Query OK,rows affected (0.01 sec)

mysql>show master status;

+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.0000011 | 260| | |
+------------------+----------+--------------+------------------+

在從服務(wù)器上執(zhí)行

先得到當(dāng)前主服務(wù)器的二進(jìn)制文件名和偏移量,執(zhí)行命令使從服務(wù)器與主服務(wù)器同步

mysql>select master_pos_wait('mysql-bin.0000011','260');
+--------------------------------------------------+
| master_pos_wait('mysql-bin.0000011','260') |
+--------------------------------------------------+
| 0 |
+--------------------------------------------------+
1 row in set (0.01 sec)

同步完成后，在主服務(wù)器上執(zhí)行解鎖

mysql>unlock tables;

切換主從服務(wù)器

當(dāng)主服務(wù)器出現(xiàn)故障時(shí)，可將從服務(wù)器當(dāng)主服務(wù)器來使用.步驟如下:

1、保證所有從數(shù)據(jù)庫都已經(jīng)執(zhí)行了relay log中的全部更新，在從服務(wù)器中執(zhí)行

stop slave io_thread,用show processlist檢查，查看狀態(tài)是否是Has read all relay log,表示更新完成.

mysql>stop slave io_thread;
Query OK,0 affected (0.00 sec)
mysql>show processlist\G;

*************************** 2. row ***************************
     Id: 2
   User: system user
   Host:
     db: NULL
Command: Connect
   Time: 4757
State: Has read all relay log; waiting for the slave I/O thread to update it
   Info: NULL

2、在從服務(wù)器上執(zhí)行stop slave，reset master命令，重置成主數(shù)據(jù)庫

mysql>stop slave;
Query OK,0 affected (0.00 sec)
mysql>reset master;
Query OK,0 affected (0.00 sec)

3、刪除新的主服務(wù)器數(shù)據(jù)庫目錄中的master.info和relay-log.info文件，否則下次重啟時(shí)還會(huì)按照從服務(wù)器來啟動(dòng).

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