基於mysqldump快速搭建從庫

基於mysqldump快速搭建從庫

mysql主從搭建總的來說大致分為3個步驟，一是為主從實例添加復制所需參數以及創建復制用的賬戶，二在是需要在主庫建立快照，三是在從庫上添加指向主庫IP，端口，用戶名，密碼，binlog位置等。而對於主從搭建的快照方式有很多種，如使用InnoDB hotbak，xtrabackup，mysqldump以及直接使用tar方式來建立快照。本文主要介紹使用mysqldump方式來建立快照，適用於不超過20GB左右的數據庫。

與本文有關的相關參考：

1、實例級別的主從搭建

-- 演示環境，另，本文演示基於同一主機的多實例，主端口為3406，從端口為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

--有關參主從數配置，請參考MySQL 復制簡要描述及示例
--創建用於復制的賬戶
master@localhost[(none)]> grant replication slave on *.* to 'repl'@'192.168.1.177' identified by 'xxx';
Query OK, 0 rows affected (0.01 sec)

--全局讀鎖
master@localhost[(none)]> flush tables with read lock;
Query OK, 0 rows affected (0.02 sec)

master@localhost[(none)]> system pwd
/data/inst3406

--獲取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導出實例
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  

--解鎖
master@localhost[(none)]> unlock tables;

master@localhost[(none)]> exit

--從庫上面導入dump
[mysql@app inst3406]$ mysql -uroot -pxxx -S /tmp/mysql3506.sock <alldb.sql

--從庫上設置主庫的相關信息(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)

--啟動slave
slave@localhost[(none)]> start slave;

2、部分庫從庫搭建

--以下演示為僅搭建部分從庫，為只同步sakila tempdb 2個庫
--重置從庫
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)

--為從庫添加只同步sakila tempdb 2個庫，以下為修改後的結果
[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

--修改後重啟3506以使從配置生效
[mysql@app ~]$ mysqladmin -uroot -pxxx -S /tmp/mysql3506.sock shutdown

[mysql@app ~]$ mysqld_safe --defaults-file=/data/inst3506/data3506/my3506.cnf &

--從主庫僅導出sakila tempdb
[mysql@app ~]$ mysqldump -uroot -pxxx -S /tmp/mysql3406.sock --single-transaction --master-data=2 -R --database sakila tempdb>multidb.sql

--在從庫端登陸執行dump文件
[mysql@app ~]$ mysqls
slave@localhost[(none)]> source multidb.sql

--查看dump期間的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;

--從庫上設置主庫的相關信息(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)

--啟動從庫
slave@localhost[tempdb]> start slave;
Query OK, 0 rows affected (0.01 sec)

-- Author : Leshami
-- Blog   : http://blog.csdn.net/leshami
--校驗結果
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期間，--single-transaction 僅僅對innodb引擎有效
--如果僅使用--master-data，則會開啟--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.