规划
master 192.168.56.2
slave 192.168.56.5
1、在主库上,设置一个复制使用的账户rep1,并授予REPLICATION SLAVE权限。
mysql> grant replication slave on *.* to 'rep1'@'192.168.56.2' identified by '123456'; Query OK, 0 rows affected (0.01 sec)
2、修改主数据库服务器的配置文件my.cnf,开启BINLOG,并设置server-id的值。这两个参数的修改需要重新启动数据库服务才可以生效。
vi /etc/my.cnf
[mysqld]
log-bin=/home/mysql/log/mysql-bin.log
server-id=1
[root@rhel6 ~]# service mysql restart Shutting down MySQL.. [ OK ] Starting MySQL. [ OK ]
3、在主库上,设置读锁定有效,这个操作是为了确保没有数据库操作,以便获得一个一致性的快照。
mysql> flush tables with read lock; Query OK, 0 rows affected (0.02 sec)
4、得到主库上当前的二进制日志名和偏移量值。这个操作的目的是为了从数据库启动以后,从这个点开始进行数据的恢复。
mysql> show master status; +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | mysqlbin.000021 | 120 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.03 sec)
5、现在主数据库服务器已经停止了更新操作,需要生成主数据库的备份,备份的方式有很多种,可以直接在操作系统下复制全部的数据文件到从数据库服务器上,也可以通过mysqldump导出数据或者使用ibbackup工具进行数据库的备份。如果主数据库的服务可以停止,那么直接复制数据文件应该是最快的生成快照的方法:
[root@rhel6 lib]# tar -zcvf mysql.tar.gz mysql mysql/ tar: mysql/mysql.sock: socket ignored mysql/mysqlbin.000019 mysql/test1/ mysql/test1/db.opt mysql/test1/pack.MYD mysql/test1/myisam2.frm mysql/test1/emp.ibd mysql/test1/mer_myisam.MRG mysql/test1/emp.frm mysql/test1/pri_t.TRG .... 传到从数据库 [root@rhel6 lib]# scp mysql.tar.gz root@192.168.56.5:/root root@192.168.56.5's password: mysql.tar.gz 100% 1402KB 1.4MB/s 00:00
6、主数据库备份完毕后可恢复写操作,剩下的只需要在从库上执行
mysql> unlock tables; Query OK, 0 rows affected (0.02 sec)
7、将主数据库的一致性备份恢复到从数据库上。如果是使用.tar.gz打包的文件包,只需要解开到相应的目录即可。
tar -zxvf mysql.tar.gz
8、修改从数据库的配置文件my.cnf,增加server-id参数。注意server-id的值必须是唯一的,不能和主数据库的配置相同,如果有多个从数据库服务器,每个从数据库服务器必须有自己唯一的server-id值。
vi my.cnf
[mysqld]
server-id=2
9、在从库上,使用--skip-slave-start选项启动数据库,这样不会立即启动从数据库服务上的复制进程,方便我们对从数据库的服务进行进一步的配置(可选)
mysqld_safe --skip-slave-start &
或者修改my.cnf,添加skip-slave-start参数,service mysql start
10、对从数据库服务器做相应设置,指定复制使用的用户,主数据库服务器的IP、端口以及开始执行复制的日志文件和位置等
mysql> change master to -> master_host='192.168.56.2', -> master_user='rep1', -> master_port=3306, -> master_password='123456', -> master_log_file='mysqlbin.000021', -> master_log_pos=120; Query OK, 0 rows affected, 2 warnings (0.08 sec)
11、在从库上,启动slave线程
mysql> start slave; Query OK, 0 rows affected (0.17 sec)
12、从库上查看进程
mysql> show processlist G; *************************** 1. row *************************** Id: 1 User: root Host: localhost db: zx Command: Query Time: 0 State: init Info: show processlist *************************** 2. row *************************** Id: 4 User: system user Host: db: NULL Command: Connect Time: 1484 State: Waiting for master to send event Info: NULL *************************** 3. row *************************** Id: 5 User: system user Host: db: NULL Command: Connect Time: 739 State: Slave has read all relay log; waiting for the slave I/O thread to update it Info: NULL 3 rows in set (0.00 sec) mysql> show slave status G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.56.2 Master_User: rep1 Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysqlbin.000021 Read_Master_Log_Pos: 652 Relay_Log_File: rhel6-relay-bin.000002 Relay_Log_Pos: 814 Relay_Master_Log_File: mysqlbin.000021 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: 652 Relay_Log_Space: 987 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: 1 Master_UUID: 3743271b-aa6d-11e6-aa2e-080027e5f5dd Master_Info_File: /mysqldata/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)
Slave_IO_Running和Slave_SQL_Running全部为YES才算搭建成功。如果出错查看报错原因。我搭建时遇到的两个错误:
(1)Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server UUIDs; these UUIDs must be different for replication to work.
原因:搭建时把主库整个目录复制过来的,主库和从库的UUID一致了,修改从库的UUID即可。
方法:修改$datadir/auto.cnf,按照16进制格式随便改一下,重启mysql即可。
(2)Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'Could not find first log file name in binary log index file'
原因:配置change master to时把master_log_file配置错误
方法:change master to master_log_file='mysqlbin.000021';start slave;即可。
13、测试复制的正确性
主库 mysql> create database zx; Query OK, 1 row affected (0.05 sec) mysql> use zx; Database changed mysql> create table t(id int); Query OK, 0 rows affected (0.09 sec) mysql> insert into t values(1),(2),(3); Query OK, 3 rows affected (0.01 sec) Records: 3 Duplicates: 0 Warnings: 0 从库 mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | data | | mysql | | performance_schema | | test | | test1 | | zx | +--------------------+ 7 rows in set (0.00 sec) mysql> use zx 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 * from t; +------+ | id | +------+ | 1 | | 2 | | 3 | +------+ 3 rows in set (0.00 sec)