查询所安装的MariaDB组件：
[root@localhost logs]# rpm -qa | grep Maria*
MariaDB-server-5.5.49-1.el7.centos.x86_64
MariaDB-common-5.5.49-1.el7.centos.x86_64
MariaDB-client-5.5.49-1.el7.centos.x86_64
[root@localhost logs]# yum -y remove mari*
查看遗留文件：
[root@localhost ~]# ls /etc/my.cnf
/etc/my.cnf
[root@localhost ~]# ll /var/lib/mysql/
total 28700
-rw-rw---- 1 mysql mysql 16384 May 5 10:31 aria_log.00000001
-rw-rw---- 1 mysql mysql 52 May 5 10:31 aria_log_control
-rw-rw---- 1 mysql mysql 18874368 May 5 10:31 ibdata1
-rw-rw---- 1 mysql mysql 5242880 May 5 10:31 ib_logfile0
-rw-rw---- 1 mysql mysql 5242880 Oct 6 2017 ib_logfile1
drwx------ 2 mysql mysql 4096 Oct 6 2017 mysql
drwx------ 2 mysql mysql 4096 Oct 6 2017 performance_schema
[root@localhost ~]# rm -rf /etc/my.cnf
[root@localhost ~]# rm -rf /var/lib/mysql/*