基于mysqldump快速搭建从库

太过爱你忘了你带给我的痛 2022-08-07 12:55 136阅读 0赞

mysql主从搭建总的来说大致分为3个步骤，一是为主从实例添加复制所需参数以及创建复制用的账户，二在是需要在主库建立快照，三是在从库上添加指向主库IP，端口，用户名，密码，binlog位置等。而对于主从搭建的快照方式有很多种，如使用InnoDB hotbak，xtrabackup，mysqldump以及直接使用tar方式来建立快照。本文主要介绍使用mysqldump方式来建立快照，适用于不超过20GB左右的数据库。

与本文有关的相关参考：  
        [使用mysqldump导出数据库  
][mysqldump_]        [MySQL 复制简要描述及示例  
][MySQL _]        [MySQL多实例配置(一)  
][MySQL_]        [MySQL多实例配置(二)][MySQL]

1、实例级别的主从搭建

-- 演示环境，另，本文演示基于同一主机的多实例，主端口为3406，从端口为3506
    master@localhost[(none)]> show variables like 'version';
    +---------------+------------+
    | Variable_name | Value      |
    +---------------+------------+
    | version       | 5.6.12-log |
    +---------------+------------+
    
    master@localhost[(none)]> system cat /etc/issue
    CentOS release 5.4 (Final)
    Kernel \r on an \m
    
    --有关参主从数配置，请参考MySQL 复制简要描述及示例
    --创建用于复制的账户
    master@localhost[(none)]> grant replication slave on *.* to 'repl'@'192.168.1.177' identified by 'xxx';
    Query OK, 0 rows affected (0.01 sec)
    
    --全局读锁
    master@localhost[(none)]> flush tables with read lock;
    Query OK, 0 rows affected (0.02 sec)
    
    master@localhost[(none)]> system pwd
    /data/inst3406
    
    --获取master binlog位置
    master@localhost[(none)]> show master status;
    +--------------------+----------+--------------+------------------+-------------------+
    | File               | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
    +--------------------+----------+--------------+------------------+-------------------+
    | inst3406bin.000001 |     2169 |              |                  |                   |
    +--------------------+----------+--------------+------------------+-------------------+
    1 row in set (0.00 sec)
    
    --使用mysqldump导出实例
    master@localhost[(none)]> system mysqldump -uroot -pxxx -S /tmp/mysql3406.sock --routines --all-databases --opt >alldb.sql
    
    master@localhost[(none)]> system ls
    alldb.sql  data3406  
    
    --解锁
    master@localhost[(none)]> unlock tables;
    
    master@localhost[(none)]> exit
    
    --从库上面导入dump
    [mysql@app inst3406]$ mysql -uroot -pxxx -S /tmp/mysql3506.sock <alldb.sql
    
    --从库上设置主库的相关信息(host,port等等)
    [mysql@app inst3506]$ mysqls
    slave@localhost[(none)]> change master to
        -> MASTER_HOST='192.168.1.177',  
        -> MASTER_USER='repl',  
        -> MASTER_PASSWORD='xxx',  
        -> MASTER_PORT=3406,  
        -> MASTER_LOG_FILE='inst3406bin.000001',  
        -> MASTER_LOG_POS=2169;  
    Query OK, 0 rows affected, 2 warnings (0.01 sec)
    
    --启动slave
    slave@localhost[(none)]> start slave;

2、部分库从库搭建

--以下演示为仅搭建部分从库，为只同步sakila tempdb 2个库
    --重置从库
    slave@localhost[(none)]> stop slave;
    Query OK, 0 rows affected (0.01 sec)
    
    slave@localhost[(none)]> reset slave all;
    Query OK, 0 rows affected (0.01 sec)
    
    --为从库添加只同步sakila tempdb 2个库，以下为修改后的结果
    [mysql@app ~]$ grep replicate /data/inst3506/data3506/my3506.cnf 
    replicate-do-db=test
    replicate-do-db=sakila
    
    [mysql@app ~]$ grep skip-slave /data/inst3506/data3506/my3506.cnf
    skip-slave-start
    
    --修改后重启3506以使从配置生效
    [mysql@app ~]$ mysqladmin -uroot -pxxx -S /tmp/mysql3506.sock shutdown
    
    [mysql@app ~]$ mysqld_safe --defaults-file=/data/inst3506/data3506/my3506.cnf &
    
    --从主库仅导出sakila tempdb
    [mysql@app ~]$ mysqldump -uroot -pxxx -S /tmp/mysql3406.sock --single-transaction --master-data=2 -R --database sakila tempdb>multidb.sql
    
    --在从库端登陆执行dump文件
    [mysql@app ~]$ mysqls
    slave@localhost[(none)]> source multidb.sql
    
    --查看dump期间的master binlog位置
    slave@localhost[tempdb]> system grep -i "change master" multidb.sql
    -- CHANGE MASTER TO MASTER_LOG_FILE='inst3406bin.000001', MASTER_LOG_POS=3293117;
    
    --从库上设置主库的相关信息(host,port等等)
    slave@localhost[tempdb]> change master to
        -> MASTER_HOST='192.168.1.177',  
        -> MASTER_USER='repl',  
        -> MASTER_PASSWORD='xxx',  
        -> MASTER_PORT=3406,  
        -> MASTER_LOG_FILE='inst3406bin.000001',  
        -> MASTER_LOG_POS=3293117; 
    Query OK, 0 rows affected, 2 warnings (0.01 sec)
    
    --启动从库
    slave@localhost[tempdb]> start slave;
    Query OK, 0 rows affected (0.01 sec)
    
    -- Author : Leshami
    -- Blog   : http://blog.csdn.net/leshami
    --校验结果
    slave@localhost[tempdb]> show slave status \G
    *************************** 1. row ***************************
                   Slave_IO_State: Waiting for master to send event
                      Master_Host: 192.168.1.177
                      Master_User: repl
                      Master_Port: 3406
                    Connect_Retry: 60
                  Master_Log_File: inst3406bin.000001
              Read_Master_Log_Pos: 3293117
                   Relay_Log_File: relay-bin.000002
                    Relay_Log_Pos: 285
            Relay_Master_Log_File: inst3406bin.000001
                 Slave_IO_Running: Yes
                Slave_SQL_Running: Yes
                  Replicate_Do_DB: test,sakila
    
    --需要注意的是，本文的mysqldump期间，--single-transaction 仅仅对innodb引擎有效
    --如果仅使用--master-data，则会开启--lock-all-tables
    The --master-data and --single-transaction options can be used simultaneously, which provides a convenient way to
           make an online backup suitable for use prior to point-in-time recovery if tables are stored using the InnoDB
           storage engine.

[mysqldump_]: http://blog.csdn.net/leshami/article/details/40144349
[MySQL _]: http://blog.csdn.net/leshami/article/details/41643013
[MySQL_]: http://blog.csdn.net/leshami/article/details/40339167
[MySQL]: http://blog.csdn.net/leshami/article/details/40339295