MySQL数据库的主从配置(多主对一从)

一、实验环境部署

主服务器 192.168.18.42 端口3306 ==》 从服务器 192.168.18.44 端口 3306

主服务器 192.168.18.43 端口3306 ==》 从服务器 192.168.18.44 端口 3307

##数据库，已经安装mysql服务，安装部分略。从服务器上的多个mysql实例，请看另一篇帖子《用mysql_multi 实现一台机器跑多台mysql 》

二、部署服务器

1.在两台主服务器上赋予从机权限，有多台丛机，就执行多次（我们这里两台主库使用统一帐号密码）。

mysql> grant replication slave on *.* to 'backup'@'192.168.18.44' identified by '123456';

Query OK, 0 rows affected (0.00 sec)

2.在主服务器上配置my.cnf

vi /etc/my.cnf

server-id = 1

log-bin = mysql-bin #保证binlog可读

read-only = 0 #主机，读写都可以

#binlog-do-db = test #需要备份数据，多个写多行，不写全部都备份

binlog-ignore-db = mysql #不需要备份的数据库，多个写多行

编辑后重启数据库 # service mysqld restart

3.配置从库服务器的my.cnf

vi /etc/my.cnf

[mysqld_multi]

mysqld = /mysql/bin/mysqld_safe

mysqladmin = /mysql/bin/mysqladmin

[mysqld1]

port = 3306

socket = /tmp/mysql3306.sock

pid-file = /data/mysql/data1/mysql3306.pid

datadir = /data/mysql/data1

skip-name-resolve

log-bin = mysql-bin-3306

log_slave_updates

expire_logs_days = 7

log-error = /data/mysql/data1/mysql3306.err

log_slow_queries = mysql3306-slow.log

long_query_time = 3

query_cache_size = 64M

query_cache_limit = 2M

slave-net-timeout = 10

server-id = 2 #server id 不要与主库的重复

master-host = 192.168.18.42 #对应主库的 ip地址

master-user = backup # slave 帐号

master-password = 123456 # 密码

master-port = 3306 #主库端口

replicate-ignore-db=mysql #跳过不备份的库

master-info-file = master.1842.info

master-connect-retry = 10

relay-log = relay-bin-1842 #中继日志

relay-log-index = relay-bin-1842

relay-log-info-file = relay-log-1842.info

default-character-set=gbk

innodb_data_home_dir = /data/mysql/data1

innodb_data_file_path = ibdata1:50M:autoextend

innodb_log_group_home_dir = /data/mysql/data1

innodb_buffer_pool_size = 3072M

innodb_file_per_table

innodb_open_files = 800

#innodb_flush_method = O_DIRECT

innodb_flush_method = O_DSYNC

skip-locking

key_buffer = 32M

max_allowed_packet = 16M

table_cache = 1024

sort_buffer_size = 8M

net_buffer_length = 8M

read_buffer_size = 2M

read_rnd_buffer_size = 8M

myisam_sort_buffer_size = 32M

max_connections = 100

read_only

wait_timeout=288000

interactive_timeout=288000

log-bin-trust-function-creators=1

replicate-ignore-db = test

replicate-ignore-table = mysql.columns_priv

replicate-ignore-table = mysql.host

replicate-ignore-table = mysql.db

replicate-ignore-table = mysql.procs_priv

replicate-ignore-table = mysql.tables_priv

replicate-ignore-table = mysql.user

[mysqld2]

port = 3307

socket = /tmp/mysql3307.sock

pid-file = /data/mysql/data2/mysql3307.pid

datadir = /data/mysql/data2

skip-name-resolve

log-bin = mysql-bin-3307

log_slave_updates

expire_logs_days = 7

log-error = /data/mysql/data1/mysql3307.err

log_slow_queries = mysql3307-slow.log

long_query_time = 3

query_cache_size = 64M

query_cache_limit = 2M

slave-net-timeout = 10

server-id = 2 #server id 不要与主库的重复

master-host = 192.168.18.43 #对应主库的 ip地址

master-user = backup # slave 帐号

master-password = 123456 # 密码

master-port = 3306 #主库端口

replicate-ignore-db=mysql #跳过不备份的库

master-info-file = master.1843.info

master-connect-retry = 10

relay-log = relay-bin-1843

relay-log-index = relay-bin-1843

relay-log-info-file = relay-log-1843.info

default-character-set=gbk

innodb_data_home_dir = /data/mysql/data2

innodb_data_file_path = ibdata1:50M:autoextend

innodb_log_group_home_dir = /data/mysql/data2

innodb_buffer_pool_size = 3072M

innodb_file_per_table

innodb_open_files = 800

#innodb_flush_method = O_DIRECT

innodb_flush_method = O_DSYNC

skip-locking

key_buffer = 32M

max_allowed_packet = 16M

table_cache = 1024

sort_buffer_size = 8M

net_buffer_length = 8M

read_buffer_size = 2M

read_rnd_buffer_size = 8M

myisam_sort_buffer_size = 32M

max_connections = 100

read_only

wait_timeout=288000

interactive_timeout=288000

log-bin-trust-function-creators=1

replicate-ignore-db = test

replicate-ignore-table = mysql.columns_priv

replicate-ignore-table = mysql.host

replicate-ignore-table = mysql.db

replicate-ignore-table = mysql.procs_priv

replicate-ignore-table = mysql.tables_priv

replicate-ignore-table = mysql.user

# 因为图方便就把参数全部抓出来了 对主从有用的也就标注的几个

4.配置完成后重启大从服务器

[root@localhost data1]# mysqld_multi --config-file=/etc/my.cnf --user=root --password=123456 report 1,2

Reporting MySQL servers

MySQL server from group: mysqld1 is running

MySQL server from group: mysqld2 is running

5.在从库上进行chang master ；

1）.在date1上

mysql -uroot -p -S /tmp/mysql3306.sock

mysql> stop slave;

Query OK, 0 rows affected (0.00 sec)

mysql> CHANGE MASTER TO

-> MASTER_HOST='192.168.18.43',

-> MASTER_PORT=3306,

-> MASTER_USER='backup',

-> MASTER_PASSWORD='123456'

Query OK, 0 rows affected (0.05 sec)

mysql> start slave;

Query OK, 0 rows affected (0.00 sec)

2）。在date2上

mysql -uroot -p -S /tmp/mysql3307.sock

mysql> stop slave;

Query OK, 0 rows affected (0.00 sec)

mysql> CHANGE MASTER TO

-> MASTER_HOST='192.168.18.42',

-> MASTER_PORT=3306,

-> MASTER_USER='backup',

-> MASTER_PASSWORD='123456'

Query OK, 0 rows affected (0.05 sec)

mysql> start slave;

Query OK, 0 rows affected (0.00 sec)

三、验证：

1.在大从服务器上

show slave status\G;

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

2.在主库创建数据库（18.43上）

mysql> create database haifengtest;

Query OK, 1 row affected (0.00 sec)

mysql> show databases;

+--------------------+

| Database |

+--------------------+

| information_schema |

| haifengtest |

| mysql |

| test |

+--------------------+

4 rows in set (0.00 sec)

从库查看 (mysql3307.sock上）

mysql> show databases;

+--------------------+

| Database |

+--------------------+

| information_schema |

| haifengtest |

| mysql |

| test |

+--------------------+

4 rows in set (0.00 sec)

四、一种常见的问题。

在show slave status\G；时发现下面的问题，（因为我事先在从上创建了该库）

Relay_Master_Log_File: mysql-bin.000005

Slave_IO_Running: Yes

Slave_SQL_Running: No

Replicate_Do_DB:

Replicate_Ignore_DB: mysql

Replicate_Do_Table:

Replicate_Ignore_Table:

Replicate_Wild_Do_Table:

Replicate_Wild_Ignore_Table:

Last_Errno: 1007

Last_Error: Error 'Can't create database 'haifengtest'; database exists' on query. Default database: 'haifengtest'. Query: 'create database haifengtest'

如果Replication在Slave上出现上面错误而停止，一般都期望Slave能忽略这个错误，继续进行同步，而不是重新启动Slave。

　这时可以使用 SQL_SLAVE_SKIP_COUNTER

mysql> SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1;

Query OK, 0 rows affected (0.00 sec)

mysql> start slave;

Query OK, 0 rows affected (0.00 sec)

在验证一次

show slave status\G;

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

ok 搞定。。。。