mysql5.6 主从同步

主库IP：192.168.220.3

从库IP：192.168.220.4

---

1、主库配置编辑my.cnf：

# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html
# *** DO NOT EDIT THIS FILE. It's a template which will be copied to the
# *** default location during install, and will be replaced if you
# *** upgrade to a newer version of MySQL.

[mysqld]

# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M

# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin

# These are commonly set, remove the # and set as required.
basedir = /usr/mysql
datadir = /usr/mysql/data
port = 3306
server_id = 1
socket = /tmp/mysql.sock 
lower_case_table_names = 1

log-bin = mysql-bin  # 启用二进制日志
server-id = 3        # 服务器唯一ID 取IP最后一段
sync_binlog = 1      # 每次事务提交则将cache中的数据写入磁盘并同步执行同步指令，此时最安全但是性能损失最大
binlog_format = mixed # binlog日志格式，mysql默认采用
binlog-do-db = db1 # 同步数据库
binlog-ignore-db = mysql # 忽略同步的数据库
binlog-ignore-db = performance_schema
binlog-ignore-db = information_schema
binlog_checksum=NONE



# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M 

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 

2、主库mysql创建同步账号

grant replication slave on *.* to slave@192.168.220.4 indentified by 'qwe123'

flush privileges;

3、主库状态

mysql> show master status;

+------------------+----------+--------------+---------------------------------------------+-------------------+
| File                      | Position | Binlog_Do_DB | Binlog_Ignore_DB                                           | Executed_Gtid_Set |
+------------------+----------+--------------+---------------------------------------------+-------------------+
| mysql-bin.000002 |      402 | db1                 | mysql,performance_schema,information_schema |                   |
+------------------+----------+--------------+---------------------------------------------+-------------------+

记录下二进制日志文件名和位置

---

4、从库配置文件配置

# 启用二进制日志
log-bin=mysql-bin   
# 服务器唯一ID，一般取IP最后一段
server-id=4

relay-log-index = slave-relay-bin.index

relay-log = slave-relay-bin

sync_master_info = 1

sync_relay_log = 1

sync_relay_log_info = 1

5、从库mysql中配置连接主库

change master to master_host='192.168.220.3',master_user='slave',master_password='qwe123', master_log_file='mysql-bin.000002',master_log_pos=402;

6、开始同步

mysql> start slave;

7、查看同步状态

mysql> show slave statusG;

Slave_IO_Running: Yes
Slave_SQL_Running: Yes

---

 备注：如果主从不同步处理方案

先上Master库：

mysql>show processlist;   查看下进程是否Sleep太多。发现很正常。

show master status; 也正常。

mysql> show master status;
+-------------------+----------+--------------+-------------------------------+
| File                        | Position | Binlog_Do_DB | Binlog_Ignore_DB              |
+-------------------+----------+--------------+-------------------------------+
| mysqld-bin.000001 |     3260 |                      | mysql,test,information_schema |
+-------------------+----------+--------------+-------------------------------+
1 row in set (0.00 sec)

再到Slave上查看

mysql> show slave statusG                                                

Slave_IO_Running: Yes

Slave_SQL_Running: No

可见是Slave不同步

下面介绍两种解决方法：

方法一：忽略错误后，继续同步

该方法适用于主从库数据相差不大，或者要求数据可以不完全统一的情况，数据要求不严格的情况

解决： 

stop slave;

#表示跳过一步错误，后面的数字可变

set global sql_slave_skip_counter =1;

start slave;

之后再用mysql> show slave statusG  查看：

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

ok，现在主从同步状态正常

方式二：重新做主从，完全同步

该方法适用于主从库数据相差较大，或者要求数据完全统一的情况

解决步骤如下：

1.先进入主库，进行锁表，防止数据写入

使用命令：

mysql> flush tables with read lock;

注意：该处是锁定为只读状态，语句不区分大小写

2.进行数据备份 

#把数据备份到mysql.bak.sql文件

[root@server01 mysql]#mysqldump -uroot -p -hlocalhost > mysql.bak.sql

3.查看master 状态

mysql> show master status;
+-------------------+----------+--------------+-------------------------------+
| File                        | Position | Binlog_Do_DB | Binlog_Ignore_DB              |
+-------------------+----------+--------------+-------------------------------+
| mysqld-bin.000001 |     3260 |                      | mysql,test,information_schema |
+-------------------+----------+--------------+-------------------------------+
1 row in set (0.00 sec)

4.把mysql备份文件传到从库机器，进行数据恢复

#使用scp命令

[root@server01 mysql]# scp mysql.bak.sql root@192.168.220.4:/tmp/

5.停止从库的状态

mysql> stop slave;

6.然后到从库执行mysql命令，导入数据备份

mysql> source /tmp/mysql.bak.sql

7.设置从库同步，注意该处的同步点，就是主库show master status信息里的| File| Position两项

change master to master_host = '192.168.220.3', master_user = 'slave', master_port=3306, master_password='qwe123', master_log_file = 'mysqld-bin.000001', master_log_pos=3260;

8.重新开启从同步

mysql> start slave;

9.查看同步状态

mysql> show slave statusG  查看：

Slave_IO_Running: Yes

Slave_SQL_Running: Yes