mysql5.7 pxc - 爱码网

pxc优点总结：
可以达到时时同步，无延迟现象发生
完全兼容MySQL
对于集群中新节点的加入，维护起来很简单
数据的强一致性
不足之处总结：
只支持Innodb存储引擎
存在多节点update更新问题，也就是写放大问题
在线DDL语句，锁表问题
sst针对新节点加入的传输代价过高的问题

关于写放大的原理图

mysql5.7 pxc

下面从上次组复制转pxc

https://www.cnblogs.com/omsql/p/9277047.html

pxc架构图如下

mysql5.7 pxc

卸载mysql

卸载前记得备份my.cnf

yum remove mysql-community-*

安装pxc

yum install http://www.percona.com/downloads/percona-release/redhat/0.1-6/percona-release-0.1-6.noarch.rpm
yum install http://rpmfind.net/linux/dag/redhat/el6/en/x86_64/dag/RPMS/socat-1.7.2.4-1.el6.rf.x86_64.rpm
yum install Percona-XtraDB-Cluster-57

修改my.cnf

#pxc
wsrep_provider=/usr/lib64/galera3/libgalera_smm.so
wsrep_cluster_address=gcomm://192.168.20.201,192.168.20.202,192.168.20.203
wsrep_slave_threads= 8
innodb_autoinc_lock_mode=2
wsrep_node_address=192.168.20.201
wsrep_cluster_name=ht-pxc-cluster
wsrep_node_name=pxc01
pxc_strict_mode=ENFORCING
wsrep_sst_method=xtrabackup-v2
wsrep_sst_auth=sst:ocm123

第一个节点启动
/etc/init.d/mysqld bootstrap-pxc
创建用户
SHOW VARIABLES LIKE 'validate_password%';
set global validate_password_policy=LOW;
set global validate_password_length=4;
create user 'sst'@'localhost' identified by 'ocm123';
grant all privileges on *.* to 'sst'@'localhost' identified by 'ocm123';
flush privileges;

第二个节点启动
/etc/init.d/mysql start
第三个节点启动
/etc/init.d/mysql start

　　添加第三个节点redis03的时候redis02日志输出如下

1 redis02
2 2018-07-09T15:01:19.004758Z 0 [Note] WSREP: Member 2.0 (pxc03) requested state transfer from '*any*'. Selected 0.0 (pxc02)(SYNCED) as donor.
3 2018-07-09T15:01:19.004800Z 0 [Note] WSREP: Shifting SYNCED -> DONOR/DESYNCED (TO: 7054)
4 2018-07-09T15:01:19.004867Z 5 [Note] WSREP: wsrep_notify_cmd is not defined, skipping notification.
5 2018-07-09T15:01:19.005039Z 0 [Note] WSREP: Initiating SST/IST transfer on DONOR side (wsrep_sst_xtrabackup-v2 --role 'donor' --address '192.168.20.203:4444/xtrabackup_sst//1' --socket '/data/mysql/mysql.sock' --datadir '/data/mysql/' --defaults-file '/etc/my.cnf' --defaults-group-suffix ''  --binlog 'mysql-bin' --gtid '62e9006b-8379-11e8-bc64-874d49a77c07:7054')
6 2018-07-09T15:01:19.087469Z 5 [Note] WSREP: DONOR thread signaled with 0

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