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8.6. Replication

8.6.1. Master Slave

8.6.1.1. Master

过程 8.1. Master 设置步骤

  1. 配置 my.cnf 文件

    确保主服务器主机上my.cnf文件的[mysqld]部分包括一个log-bin选项。该部分还应有一个server-id=Master_id选项

    # vim /etc/mysql/my.cnf
    
    server-id               = 1
    log_bin                 = /var/log/mysql/mysql-bin.log
    expire_logs_days        = 10
    max_binlog_size         = 100M
    binlog_do_db            = test
    binlog_ignore_db        = mysql
    					

    bind-address默认是127.0.0.1你必须更改它,否则Slave将无法链接到 Master

    #bind-address		= 127.0.0.1
    bind-address		= 0.0.0.0
    					

    重启服务器

    neo@netkiller:~$ sudo /etc/init.d/mysql reload
     * Reloading MySQL database server mysqld          [ OK ]
    					

    建议使用reload,如果不起作用再用restart

    					
    mysql> SHOW GLOBAL VARIABLES like 'server_id';
    +---------------+-------+
    | Variable_name | Value |
    +---------------+-------+
    | server_id     | 1     |
    +---------------+-------+
    1 row in set (0.00 sec)
    					
    					
  2. 登录slave服务器,测试主库3306工作情况,如果看到下面相关信息表示工作正常。

    					
    # telnet 192.168.1.246 3306
    Trying 192.168.1.246...
    Connected to 192.168.1.246.
    Escape character is '^]'.
    I
    5.1.61-0ubuntu0.11.10.1-log1W<gs/*'#}p<u[J=5//:
    					
    					
  3. 创建账户并授予REPLICATION SLAVE权限

    					
    mysql> GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'replication'@'%.mydomain.com' IDENTIFIED BY 'slavepass';
    mysql> FLUSH PRIVILEGES;
    					
    					

    创建监控账号monitor(可选项),monitor 使用SHOW MASTER STATUS和SHOW SLAVE STATUS命令但没有复制权限

    GRANT REPLICATION CLIENT ON *.* TO monitor@'192.168.245.131' IDENTIFIED BY 'monitorpass'

  4. 锁表禁止写入新数据

    					
    mysql> FLUSH TABLES WITH READ LOCK;
    					
    					
  5. 查看Master 工作状态

    					
    mysql> SHOW MASTER STATUS;
    +------------------+----------+--------------+------------------+
    | File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
    +------------------+----------+--------------+------------------+
    | mysql-bin.000002 |      106 | test         | mysql            |
    +------------------+----------+--------------+------------------+
    1 row in set (0.00 sec)
    					
    					

    如果显示下面内容表示,配置不正确

    					
    
    mysql> SHOW MASTER STATUS;
    Empty set (0.02 sec)
    					
    					

    取得快照并记录日志名和偏移量后,可以在主服务器上重新启用写活动

    					
    mysql> UNLOCK TABLES;
    					
    					

8.6.1.2. Slave

过程 8.2. Slave 设置步骤

  1. 配置my.cnf

    从服务器的ID必须与主服务器的ID不相同,如果设置多个从服务器,每个从服务器必须有一个唯一的server-id值,必须与主服务器的以及其它从服务器的不相同。

    # vim /etc/mysql/my.cnf
    
    [mysqld]
    server-id               = 2
    					
  2. # service mysql restart
    mysql start/running, process 22893
    					
  3. 指定 master 相关参数

    在从服务器上执行下面的语句,用你的系统的实际值替换选项值

    					
    mysql> CHANGE MASTER TO
    	->     MASTER_HOST='master_host_name',
    	->     MASTER_USER='replication_user_name',
        ->     MASTER_PASSWORD='replication_password',
        ->     MASTER_LOG_FILE='recorded_log_file_name',
        ->     MASTER_LOG_POS=recorded_log_position;
    	   				
    					

    如果是全新服务器,空数据库可以忽略MASTER_LOG_FILE与MASTER_LOG_POS

    CHANGE MASTER TO MASTER_HOST='192.168.245.129', MASTER_USER='replication', MASTER_PASSWORD='slavepass';
    					

    如果是复制已经存在的数据库需要MASTER_LOG_FILE与MASTER_LOG_POS选项

    首先到Master上运行 show master status 找到File与Position

    					
    mysql> show master status \G
    *************************** 1. row ***************************
                File: mysql-bin.000009
            Position: 3988
        Binlog_Do_DB:
    Binlog_Ignore_DB:
    1 row in set (0.00 sec)
    					
    					
    CHANGE MASTER TO
         MASTER_HOST='192.168.2.1',
         MASTER_USER='replication',
         MASTER_PASSWORD='kJZBTo3BjMx9AnmD9Ryn',
         MASTER_LOG_FILE='mysql-bin.000009',
         MASTER_LOG_POS=3988;
    					
  4. 启动从服务器线程

    					
    mysql> START SLAVE;
    Query OK, 0 rows affected (0.00 sec)
    					
    					
  5. SLAVE STATUS

    					
    mysql> SHOW SLAVE STATUS\G
    *************************** 1. row ***************************
                 Slave_IO_State: Connecting to master
                    Master_Host: 192.168.245.129
                    Master_User: repl
                    Master_Port: 3306
                  Connect_Retry: 60
                Master_Log_File:
            Read_Master_Log_Pos: 4
                 Relay_Log_File: mysqld-relay-bin.000002
                  Relay_Log_Pos: 98
          Relay_Master_Log_File:
               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: 0
                Relay_Log_Space: 98
                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: NULL
    1 row in set (0.00 sec)
    					
    					

8.6.1.3. Testing

  1. 登录 master

    复制进程的信息

    SHOW PROCESSLIST语句可以提供在主服务器上和从服务器上发生的关于复制的信息

    mysql> SHOW PROCESSLIST\G
    *************************** 1. row ***************************
         Id: 62
       User: replication
       Host: ken-hx409.local:36465
         db: NULL
    Command: Binlog Dump
       Time: 679
      State: Has sent all binlog to slave; waiting for binlog to be updated
       Info: NULL
    *************************** 2. row ***************************
         Id: 64
       User: root
       Host: localhost
         db: NULL
    Command: Query
       Time: 0
      State: NULL
       Info: SHOW PROCESSLIST
    2 rows in set (0.00 sec)
    
    					
  2. 登录从库,查看复制线程

    					
    mysql> SHOW PROCESSLIST\G
    *************************** 1. row ***************************
         Id: 273
       User: root
       Host: localhost
         db: NULL
    Command: Query
       Time: 0
      State: NULL
       Info: SHOW PROCESSLIST
    *************************** 2. row ***************************
         Id: 276
       User: system user
       Host:
         db: NULL
    Command: Connect
       Time: 2
      State: Waiting for master to send event
       Info: NULL
    *************************** 3. row ***************************
         Id: 277
       User: system user
       Host:
         db: NULL
    Command: Connect
       Time: 2
      State: Has read all relay log; waiting for the slave I/O thread to update it
       Info: NULL
    3 rows in set (0.00 sec)
    					
    					

    如果没有复制进程,请使用start slave;启动

    					
    mysql> SHOW PROCESSLIST\G
    *************************** 1. row ***************************
         Id: 273
       User: root
       Host: localhost
         db: NULL
    Command: Query
       Time: 0
      State: NULL
       Info: SHOW PROCESSLIST
    1 row in set (0.02 sec)
    
    mysql> start slave;
    Query OK, 0 rows affected (0.00 sec)
    					
    					
  3. 登录 master

    					
    mysql> insert into foo(id,data) values(2,'Hello world!!!');
    Query OK, 1 row affected (0.00 sec)
    					
    					
  4. 登录 slave

    					
    mysql> select * from foo;
    					
    					

    在master服务器上插入一条记录,你可以立刻在slave服务器上看到变化。

8.6.1.4. 将现有数据库迁移到主从结构数据库

数据库已经存在的情况下怎么迁移

  1. Master 锁表禁止写入新数据

    					
    mysql> FLUSH TABLES WITH READ LOCK;
    					
    					
  2. Slave 停止复制进程

    					
    mysql> stop slave;
    					
    					
  3. 备份Master数据库

    					
    mysqldump yourdb | gzip > yourdb.sql.gz
    					
    					
  4. 恢复数据库

    如果使用mysqldump备份主服务器的数据,将转储文件装载到从服务器

    					
    # zcat yourdb.sql.gz | mysql -u root -p yourdb
    					
    					
  5. 启动 Slave 复制进程

    					
    mysql> start slave;
    					
    					
  6. 解除 Master 表锁定

    					
    mysql> UNLOCK TABLES;
    					
    					

MyIASM引擎可以采用下面方法

备份数据库

# tar zcvf mysql-snapshot.tar.gz /var/lib/mysql/neo
			

复制给从数据库

scp mysql-snapshot.tar.gz  neo@192.168.245.131:/tmp
			

snapshot 恢复

$ tar zxvf mysql-snapshot.tar.gz
$ cd /var/lib/mysql

$ mv /tmp/var/lib/mysql/neo .
$ sudo chown mysql.mysql -R neo
			

重新启动Mysql

$ sudo /etc/init.d/mysql restart
			

有兴趣可以看看mysqlhotcopy

8.6.1.5. 主从复制安全问题

复制帐号权限

grant replication slave on *.* to 'replication'@'192.168.1.%' identified by '000000';
			

主库数据库操作帐号权限

grant DELETE, INSERT, SELECT, UPDATE ON your_user.* to yourdb@'your_host' identified by 'password' with grant option;
			

从库数据库操作帐号权限

grant SELECT ON your_user.* to yourdb@'your_host' identified by 'password' with grant option;
			

从库必须收回写操作

8.6.2. Master Master(主主)

8.6.2.1. Master A

my.cnf 文件加入下面的内容

cp /etc/mysql/my.cnf /etc/mysql/my.cnf.old
vim /etc/mysql/my.cnf

[mysqld]
server-id = 1
log-bin=/data/mysql/binlog/binlog
binlog-do-db = test
binlog-ignore-db=mysql

log-slave-updates
sync_binlog=1
auto_increment_offset=1
auto_increment_increment=2
replicate-do-db = test
replicate-ignore-db = mysql,information_schema
			

创建复制权限

grant replication slave on *.* to 'replication'@'192.168.1.%' identified by '000000';
flush privileges;
			
			
mysql>flush tables with read lock;

mysql> show master status\G
*************************** 1. row ***************************
File: binlog.000007
Position: 107
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
1 row in set (0.00 sec)
			
			

8.6.2.2. Master B

创建复制权限

grant replication slave on *.* to 'replication'@'192.168.1.%' identified by '000000';
flush privileges;
			

my.cnf 文件加入下面的内容

[mysqld]
server-id = 2
log-bin = /data/mysql/binlog/binlog
replicate-do-db = test
replicate-ignore-db = mysql,information_schema

binlog-do-db = test
binlog-ignore-db=mysql
log-slave-updates
sync_binlog=1
auto_increment_offset=2
auto_increment_increment=2
			

B 与 A 配置文件不同的两处。

server-id = 2
auto_increment_offset=2
			
			
mysql> show master status\G
*************************** 1. row ***************************
File: binlog.000005
Position: 107
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
1 row in set (0.00 sec)
			
			

8.6.2.3. 将Master A 数据库 同步到 Master B 两端数据库内容保持一致

Master A,首先锁表为只读状态

			
mysqldump --databases test > /tmp/test.sql
			
			

Master B 创建一个与Master A同名的空数据库,然后将备份文件恢复到数据库中

			
# mysql
mysql> CREATE DATABASE test;
mysql>\q

# scp 192.168.1.1:/tmp/test.sql ./
# mysql -uroot -p test < /tmp/test.sql
  			
			

8.6.2.4. Master A - B 同步两端数据库

master-A

			
mysql>change master to master_host='192.168.1.2', master_user='replication', master_password='000000', master_log_file='binlog.000005', master_log_pos=107;
			
			

master-B

			
mysql>change master to master_host='192.168.1.1', master_user='replication', master_password='000000', master_log_file='binlog.000007', master_log_pos=107;
			
			

8.6.2.5. Master A 数据库解除只读权限

Master A 解锁

			
mysql> UNLOCK TABLES;
			
			

8.6.2.6. 查看主主的工作状态

分别在Master A与B 上运行

			
mysql>show slave status\G;

Slave_IO_Running: Yes
Slave_SQL_Running: Yes
			
			

8.6.3. Semisynchronous Replication

8.6.3.1. Master

			
mysql> SHOW VARIABLES LIKE "have_dynamic_loading";
+----------------------+-------+
| Variable_name        | Value |
+----------------------+-------+
| have_dynamic_loading | YES   |
+----------------------+-------+
1 row in set (0.00 sec)

mysql>
			
			

Master 配置

mysql> install plugin rpl_semi_sync_master SONAME 'semisync_master.so';
mysql> set global rpl_semi_sync_master_enabled = 1; 
mysql> set global rpl_semi_sync_master_timeout = 30;
mysql> select * from mysql.plugin;
+----------------------+--------------------+
| name                 | dl                 |
+----------------------+--------------------+
| rpl_semi_sync_master | semisync_master.so |
+----------------------+--------------------+
1 row in set (0.00 sec)
			

状态查看

mysql> SHOW VARIABLES LIKE "%semi%";
+------------------------------------+-------+
| Variable_name                      | Value |
+------------------------------------+-------+
| rpl_semi_sync_master_enabled       | ON    |
| rpl_semi_sync_master_timeout       | 10    |
| rpl_semi_sync_master_trace_level   | 32    |
| rpl_semi_sync_master_wait_no_slave | ON    |
+------------------------------------+-------+
4 rows in set (0.00 sec)			
			

8.6.3.2. Slave 配置

install plugin rpl_semi_sync_slave soname 'semisync_slave.so';
set global rpl_semi_sync_slave_enabled = 1;
stop slave io_thread;
start slave io_thread;			
			

Slave 状态查看

show global status like 'rpl_semi%';
			

8.6.3.3. 卸载插件

卸载插件 UNINSTALL PLUGIN plugin_name

UNINSTALL PLUGIN rpl_semi_sync_master; 	
UNINSTALL PLUGIN rpl_semi_sync_slave; 			
			

8.6.3.4. my.cnf

编辑my.cnf加入

# On Master
[mysqld]
rpl_semi_sync_master_enabled=1
rpl_semi_sync_master_timeout=1000 # 1 second

# On Slave
[mysqld]
rpl_semi_sync_slave_enabled=1
			

8.6.4. multi-master replication

MySQL 5.7 以上版本才能使用

		
 master1  ---------> master2
    ^                   |
    |                   |
    |                   |
    |                   V
 master4  <--------- master3
 		
		

8.6.5. multi-source replication

MySQL 5.7 以上版本才能使用

		
 master1    master2    master3    master4
    |          |          |          |
    |          |          |          |
    |          |          |          |
    `--------------------------------'
                    |
                    V
                  Slave
 		
		

slave 配置

		
slave> change master to master_host="172.16.0.1", master_port=3306, master_user="replication",master_password="password" for channel="master1";
slave> change master to master_host="172.16.0.2", master_port=3306, master_user="replication",master_password="password" for channel="master2";

slave> start slave for channel="master1";
slave> start slave for channel="master2";
		
		

检查从服务器状态

		
slave > SHOW SLAVE STATUS FOR CHANNEL="master1"\G
slave > SHOW SLAVE STATUS FOR CHANNEL="master2"\G
		
		

测试,分别在两个主服务器上创建数据库,然后查看从数据库同步结果.

		
master1 > create database master1;
master2 > create database master2;

slave > show databases like 'master%';
+--------------------+
| Database (master%) |
+--------------------+
| master1            |
| master2            |
+--------------------+

		
		

8.6.6. 与复制有关的问题

8.6.6.1. 主从不同步问题

执行下面语句

stop slave;
set global sql_slave_skip_counter =1 ;
start slave;

mysql> slave stop;
mysql> set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;
mysql> slave start;
			

Seconds_Behind_Master 值从NULL变为大于等于0是表示已经同步

Seconds_Behind_Master: NULL
Seconds_Behind_Master: 8893
			

8.6.6.2. mysql-bin 清理问题

缺省expire-logs-days为30天。这里设为7天,可根据自己情况调整。

[mysqld]
expire-logs-days = 7
			

通过SQL删除

删除某个日志:	mysql>PURGE MASTER LOGS TO ‘mysql-bin.015′;
删除某天前的日志:	mysql>PURGE MASTER LOGS BEFORE ’2010-10-25  14:00:00′;
			

8.6.6.3. 跳过 Last_Errno

修改mysql配置文件 /etc/my.cnf 在 [mysqld]下加一行

[mysqld]
slave_skip_errors = 1062
			

跳过所有错误

slave-skip-errors=all			
			

8.6.6.4. 重置Slave

STOP SLAVE; 
RESET SLAVE; 
START SLAVE;			
			

8.6.7. GTID

5.6 新增功能

mysql> show global variables like '%gtid%';
+---------------------------------+-------+
| Variable_name                   | Value |
+---------------------------------+-------+
| binlog_gtid_simple_recovery     | OFF   |
| enforce_gtid_consistency        | OFF   |
| gtid_executed                   |       |
| gtid_mode                       | OFF   |
| gtid_owned                      |       |
| gtid_purged                     |       |
| simplified_binlog_gtid_recovery | OFF   |
+---------------------------------+-------+
7 rows in set (0.00 sec)		
		

8.6.7.1. Master

[root@master mysql]# vim my.cnf

binlog-format=ROW
log-slave-updates=true
gtid-mode=on
enforce-gtid-consistency=true
master-info-repository=TABLE
relay-log-info-repository=TABLE
sync-master-info=1
slave-parallel-workers=2

binlog-checksum=CRC32
master-verify-checksum=1
slave-sql-verify-checksum=1
binlog-rows-query-log_events=1
port=3306
report-host=192.168.1.21
report-port=3306
server_id = 1
			

创建有复制权限的用户

GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'replication'@'%.mydomain.com' IDENTIFIED BY 'slavepass';
FLUSH PRIVILEGES;						
			

8.6.7.2. Slave

[root@slave mysql]# vim my.cnf

relay-log = relay-log
relay-log-index = relay-log.index
binlog-format=ROW
log-slave-updates=true

gtid-mode=on
enforce-gtid-consistency=true

master-info-repository=TABLE
relay-log-info-repository=TABLE
sync-master-info=1
slave-parallel-workers=2

;binlog-checksum=CRC32
master-verify-checksum=1
slave-sql-verify-checksum=1

binlog-rows-query-log_events=1
report-port=3306
port=3306
report-host=192.168.1.22
server_id = 10	
			

登录到Master并进行复制

CHANGE MASTER TO
     MASTER_HOST='192.168.2.1',
     MASTER_USER='replication',
     MASTER_PASSWORD='kJZBTo3BjMx9AnmD9Ryn',
     MASTER_AUTO_POSITION=1;     
			

就这么简单,你不再需要指定 MASTER_LOG_FILE='mysql-bin.000009', MASTER_LOG_POS=3988 两个参数。

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