mysql数据库互为主从配置方法分享

mysql主从配置小记：
共有四台机器：a(10.1.10.28),b(10.1.10.29),c(10.1.10.30),d(10.1.10.31)。
配置后结果：a-c互为主从，b为a的slave，d为c的slave。

0)准备工作
在四台机器上面安装好mysql后，创建用于同步的账号。
添加账户：

insert into user (host,user, password,select_priv,insert_priv,update_priv,delete_priv, create_priv,drop_priv) values('%','test',password('test'),'y','y','y','y','y','y');

刷新数据库：

flush privileges;

1)配置a-c互为主从
修改a配置文件为：

server-id = 1
replicate-do-db=test
replicate-do-db=test_admin
log-bin=mysql-bin
log-slave-updates
replicate-wild-do-table=test.%
replicate-wild-do-table=test_admin.%
binlog-ignore-db=mysql
slave-skip-errors=all

修改c配置文件为：

server-id = 3
binlog-do-db=test
binlog-do-db=test_admin
log-bin=mysql-bin
log-slave-updates
replicate-wild-do-table=test.%
replicate-wild-do-table=test_admin.%
binlog-ignore-db=mysql
slave-skip-errors=all

重启mysql是配置生效
将a设置为主：
停止同步：

slave stop;

清空服务器master日志：

reset master;

授权同步账号：

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

刷新授权:

flush privileges;

锁定数据库:

flush tables with read lock;

将c设置为从：
停止同步：

slave stop;

配置同步信息：

change master to master_host='10.1.10.28', master_user='test', master_password='test', master_log_file='mysql-bin.000001', master_log_pos=107;

将c设置为主：
停止同步：

slave stop;

清空服务器master日志：

reset master;

授权同步账号：

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

刷新授权:

flush privileges;

锁定数据库:

flush tables with read lock;

将a设置为从：
停止同步：

slave stop;

配置同步信息：

change master to master_host='10.1.10.30', master_user='test', master_password='test', master_log_file='mysql-bin.000001', master_log_pos=107;

2)将b设置为a的从

server-id = 2
replicate-do-db=test
replicate-do-db=test_admin
log-bin=mysql-bin
log-slave-updates
replicate-wild-do-table=test.%
replicate-wild-do-table=test_admin.%
binlog-ignore-db=mysql
slave-skip-errors=all

重启mysql服务
停止同步：

slave stop;

配置同步信息：

change master to master_host='10.1.10.28', master_user='test', master_password='test', master_log_file='mysql-bin.000001', master_log_pos=107;

启动同步:

slave start;

3)将d设置为c的从

server-id = 4
replicate-do-db=test
replicate-do-db=test_admin
log-bin=mysql-bin
log-slave-updates
replicate-wild-do-table=test.%
replicate-wild-do-table=test_admin.%
binlog-ignore-db=mysql
slave-skip-errors=all

重启mysql服务
停止同步：

slave stop;

配置同步信息：

change master to master_host='10.1.10.30', master_user='test', master_password='test', master_log_file='mysql-bin.000001', master_log_pos=107;

启动同步:

slave start;

完成之后可以创建添加数据测试一下是否可以。
下面是常见错误处理：

1）
change master导致的：
last_io_error: error connecting to master 'repl1@ip:3306' - retry-time: 60 retries
2）
在没有解锁的情况下停止slave进程：
mysql> stop slave;
error 1192 (hy000): can't execute the given command because you have active locked tables or an active transaction
3）
change master语法错误，落下逗号
mysql> change master to
-> master_host='ip'
-> master_user='user',
-> master_password='passwd',
-> master_log_file='mysql-bin.000002',
-> master_log_pos=106;
error 1064 (42000): you have an error in your sql syntax; check the manual that corresponds to your mysql server version for the right syntax to use near 'master_user='user',
master_password='passwd',
master_log_file='mysql-bin.000002' at line 3

4）
在没有停止slave进程的情况下change master
mysql> change master to master_host=‘ip', master_user='user', master_password='passwd', master_log_file='mysql-bin.000001',master_log_pos=106;
error 1198 (hy000): this operation cannot be performed with a running slave; run stop slave first

5）
a b的server-id相同：
last_io_error: fatal error: the slave i/o thread stops because master and slave have equal mysql server ids;
these ids must be different for replication to work (or the --replicate-same-server-id option must be used on
slave but this does not always make sense; please check the manual before using it).
查看server-id
mysql> show variables like 'server_id';
手动修改server-id
mysql> set global server_id=2; #此处的数值和my.cnf里设置的一样就行
mysql> slave start;
6）change master之后，查看slave的状态，发现slave_io_running 为no