MySQL从库上有一个IO线程负责从主库取binlog到写到本地。另外有一个SQL线程负责执行这些本地日志,实现命令重放;
一、环境
主机:
master操作系统:centos5.3
IP:192.168.1.222
MySQL版本:5.0.77
从机:
slave操作系统:centos5.3
IP:192.168.1.220
MySQL版本:5.0.77
二、创建数据库
分别登录master机和slave机的mysql:mysql –u root–p
创建数据库:create databaserepl;
三、master机和slave机的相关配置
1、修改master机器中mysql配置文件my.cnf,该文件在/etc目录下
在[mysqld]配置段添加如下字段
server-id=1
log-bin=log
binlog-do-db=repl//需要同步的数据库,如果没有本行,即表示同步所有的数据库
binlog-ignore-db=mysql//被忽略的数据库
在master机上为slave机添加一同步帐号grant replication slave on *.* to'repl'@'192.1681.220' identified by '123456';
重启master机的mysql服务:service mysqldrestart
用show masterstatus命令看日志情况
mysql>show masterstatus;
+-----------------+------------+-------------------+-----------------------+
|File|Position | Binlog_Do_DB |Binlog_Ignore_DB |
+-----------------+------------+-------------------+-----------------------+
|log.000003| 98|repl |mysql |
+-----------------+------------+-------------------+-----------------------+
1 row in set (0.00 sec)
2、修改slave机中mysql配置文件
同样在[mysqld]字段下添加如下内容
server-id=2
master-host=192.168.1.222
master-user=repl
master-password=123456
master-port=3306
master-connect-retry=60# replicate-ignore-db=mysql 忽略的数据库 # master-connect-retry=60如果从服务器发现主服务器断掉,重新连接的时间差(秒)
#replicate-do-db=repl//同步的数据库(需要备份的数据库名),不写本行表示同步所有数据库
然后重启slave机的mysql
在slave机中进入mysql
mysql>startslave;
mysql>show slavestatus\G;如果Slave_IO_Running、Slave_SQL_Running状态为Yes则表明设置成功。
四、出现的问题
当我在执行startslave这条命令时,系统提示
ERROR 1200 (HY000): The server is not configuredas slave; fix in config file or with CHANGE MASTERTO,
执行show slavestatus;又提示Empty set (0.00sec),想不通问题在哪里
后来发现,原来slave已经默认开启,要先关闭再开启
执行slave stop;
再执行(此处的与写入配置文件相同)
change master to master_host='192.168.1.222',master_user='repl',master_password='123456',master_log_file='log.000003' ,master_log_pos=98;
然后执行slave start;
这时再执行show slavestatus\G
显示如下:
*************************** 1. row***************************
Slave_IO_State:Waiting for master to send event
Master_Host:192.168.1.222
Master_User:repl
Master_Port:3306
Connect_Retry:60
Master_Log_File:log.000003
Read_Master_Log_Pos:98
Relay_Log_File:mysqld-relay-bin.000002
Relay_Log_Pos:229
Relay_Master_Log_File:log.000003
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:98
Relay_Log_Space:229
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
1row in set (0.00 sec)
显示红色那两行,说明配置成功。
如果出现:
Slave_IO_Running:No
Slave_SQL_Running:Yes
……
Last_IO_Error: Fatal error: 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).
的错误
检查从库的server_id(其实此处我在配置文件中已经设置为2和主库不相同了但查看时还是为1,不明白问题在哪)
mysql> show variables like 'server_id';
手动修改
mysql> set global server_id=2; #此处的数值和my.cnf里设置的一样就行
mysql> slave start;
五、测试主从服务器是否能同步
在主服务器上面新建一个表,必须在repl数据下
mysql> use repl
Database changed
mysql> create table test(idint,name char(10));
Query OK, 0 rows affected (0.00sec)
mysql> insert into testvalues(1,'zaq');
Query OK, 1 row affected (0.00sec)
mysql> insert into testvalues(1,'xsw');
Query OK, 1 row affected (0.00sec)
mysql> select * fromtest;
+------+------+
|id|name |
+-------+------+
|1 |zaq |
|1 | xsw |
+-------+------+
2rows in set (0.00 sec)
在从服务器查看是否同步过来
mysql> use repl;
Database changed
mysql> select * fromtest;
+------+------+
|id|name |
+------+------+
|1| zaq|
|1| xsw|
+------+------+
2rows in set (0.00 sec)
说明已经配置成功