简介
Part1:写在最前
在之前的博文中有说到MaxScale，作为中间件，配合MHA使用或者主从使用可实现读写分离和负载均衡，今天简单介绍下MaxScale作为Binlog Server来减少主从延迟的问题；MySQL的主从架构中，链式拓扑的架构比较容易出现主从延迟的问题。本文着重介绍MaxScale作为Binlog Server是如何降低主从延迟的。
MaxScale配合MHA请移步至：
http://suifu.blog.51cto.com/9167728/1869520
Part2:本文环境
HE1:192.168.1.248 slave
HE3:192.168.1.250 master
HE4:192.168.1.251 maxscale
架构演示
效果对比
实战
Part1:安装maxscale
[root@HE4 ~]# yum -y install maxscale-2.0.1-2.centos.6.x86_64.rpm
[root@HE4 ~]# mkdir -p /data/binlog
[root@HE4 ~]# useradd maxscale
[root@HE4 ~]# chown -R maxscale. /data/binlog
[root@HE4 ~]# cat /etc/maxscale.cnf
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[maxscale]
threads=1
##根据CPU核数设置
[Replication]
type
=service
router=binlogrouter
user=mysync
passwd
=MANAGER
# 使用主库上的repl复制账号
# 权限：
# GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'repl'@'%' IDENTIFIED BY 'repl';
router_options=server_id=1251,heartbeat=30,binlogdir=
/data/binlog
,transaction_safety=1,mariadb10-compatibility=1,send_slave_heartbeat=1
# server_id设置maxscale的，记得不能与主和从库重复，要唯一
# heartbeat=30秒，意思为当maxscale在30秒内没有接收到主库推送的binlog日志，发送心跳检查
# binlogdir设置接收binlog的存放路径，目录属性chown -R maxscale.maxscale /data/binlog
# transaction_safety=1此参数用于启用binlog日志中的不完整事务检测。 当MariaDB MaxScale启动时，如果当前binlog文件已损坏或找到不完整的事务，则可能会出现错误消息。 在正常工作期间，binlog事件不会分配到从库，直到事务已经提交。 默认值为off，设置transaction_safety = on以启用不完全事务检测。
# send_slave_heartbeat=1开启心跳检查
[Replication Listener]
type
=listener
service=Replication
protocol=MySQLClient
port=5308
# 后端的从库CHANGE MASTER TO这个端口，默认5308
[CLI]
type
=service
router=cli
[CLI Listener]
type
=listener
service=CLI
protocol=maxscaled
port=6603
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Part2:启动Maxscale
[root@HE4 ~]# /etc/init.d/maxscale start
Starting MaxScale: maxscale (pid 16680) is running... [ OK ]
[root@HE4 ~]# /etc/init.d/maxscale status
Checking MaxScale status: MaxScale (pid 16680) is running.[ OK ]
Part3:从库配置
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[root@HE1 ~]
# mysql -umysync -pMANAGER -h192.168.1.251 -P5308
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection
id
is 3196
Server version: 10.0.0 2.0.1-maxscale
Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.
Type
'help;'
or
'\h'
for
help. Type
'\c'
to
clear
the current input statement.
MySQL [(none)]> CHANGE MASTER TO MASTER_HOST=
'192.168.1.250'
,MASTER_USER=
'mysync'
,MASTER_PASSWORD=
'MANAGER'
,MASTER_PORT=3306,MASTER_LOG_FILE=
'mysql-bin.000005'
,MASTER_LOG_POS=20;
ERROR 1234 (42000): Can not
set
MASTER_LOG_POS to 20: Permitted binlog pos is 4. Specified master_log_file=mysql-bin.000005
MySQL [(none)]> CHANGE MASTER TO MASTER_HOST=
'192.168.1.250'
,MASTER_USER=
'mysync'
,MASTER_PASSWORD=
'MANAGER'
,MASTER_PORT=3306,MASTER_LOG_FILE=
'mysql-bin.000005'
,MASTER_LOG_POS=4;
MySQL [(none)]> start slave;
Query OK, 0 rows affected (0.00 sec)
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这里可以看出，Maxscale binlog server只能从位置4开始配置
配置好后，在/data/binlog下生成的binlog文件
[root@HE4 ~]# cd /data/binlog/
[root@HE4 binlog]# ls
cache master.ini mysql-bin.000003
Part4:主库配置
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[root@HE3 ~]
# mysql -uroot -p
Enter password:
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection
id
is 7
Server version: 10.1.16-MariaDB MariaDB Server
Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.
Type
'help;'
or
'\h'
for
help. Type
'\c'
to
clear
the current input statement.
MariaDB [(none)]> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000005 | 652 | | |
+------------------+----------+--------------+------------------+
1 row
in
set
(0.00 sec)
MariaDB [(none)]> grant replication client,replication slave on *.* to
'mysync'
@
'192.168.1.%'
identified by
'MANAGER'
;
MariaDB [(none)]>flush privileges;
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Part5:主从配置
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从库指向binlogserver
[root@HE1 ~]
# mysql -uroot -pMANAGER
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection
id
is 5
Server version: 10.1.16-MariaDB MariaDB Server
Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.
Type
'help;'
or
'\h'
for
help. Type
'\c'
to
clear
the current input statement.
MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST=
'192.168.1.251'
,MASTER_USER=
'mysync'
,MASTER_PASSWORD=
'MANAGER'
,MASTER_PORT=5308,MASTER_LOG_FILE=
'mysql-bin.000005'
,MASTER_LOG_POS=652;
Query OK, 0 rows affected (0.02 sec)
MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting
for
master to send event
Master_Host: 192.168.1.251
Master_User: mysync
Master_Port: 5308
Connect_Retry: 60
Master_Log_File: mysql-bin.000005
Read_Master_Log_Pos: 652
Relay_Log_File: mysql-relay-bin.000002
Relay_Log_Pos: 537
Relay_Master_Log_File: mysql-bin.000005
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: 652
Relay_Log_Space: 835
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: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1250
Master_SSL_Crl:
Master_SSL_Crlpath:
Using_Gtid: No
Gtid_IO_Pos:
Replicate_Do_Domain_Ids:
Replicate_Ignore_Domain_Ids:
Parallel_Mode: conservative
1 row
in
set
(0.00 sec)
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——总结——
生产环境中，大多采用的是一主多从架构，例如星状拓扑和链式拓扑，星状拓扑在从库过多的情况下，会增加主库的io压力，而链式拓扑虽然缓解了主库的网络IO压力，但其缺点是：二级Slave得到最新的数据，需要再经过一层的复制才到达，期间的延迟比一主多从架构要大。而采用maxscale binlog server则避免了这类问题。由于笔者的水平有限，编写时间也很仓促，文中难免会出现一些错误或者不准确的地方，不妥之处恳请读者批评指正。
本文转自 dbapower 51CTO博客，原文链接：http://blog.51cto.com/suifu/1878847，如需转载请自行联系原作者
