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
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
[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
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 ]
Part2:从库配置
[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)
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
Part2:主库配置
[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;
Part3:主从配置
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)
——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。
本文出自 “贺磊的技术博客” 博客，请务必保留此出处http://suifu.blog.51cto.com/9167728/1878847
原文地址：http://suifu.blog.51cto.com/9167728/1878847
