数据库挂了，如何根据这些信息定位问题？

打开网站，发现网站报错，提示数据库连接失败。

打开阿里云，查看数据库服务状态，如下：

Welcome to aliyun Elastic Compute Service!

[root@iZ94r80gdghZ ~]# ls
[root@iZ94r80gdghZ ~]# service mariadb status
Redirecting to /bin/systemctl status  mariadb.service
● mariadb.service - MariaDB database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/mariadb.service.d
           └─migrated-from-my.cnf-settings.conf
   Active: failed (Result: timeout) since 日 2016-04-10 19:32:47 CST; 2h 0min ago
  Process: 14771 ExecStart=/usr/sbin/mysqld $MYSQLD_OPTS $_WSREP_NEW_CLUSTER (code=exited, status=0/SUCCESS)
 Main PID: 14771 (code=exited, status=0/SUCCESS)
   Status: "MariaDB server is down"

4 月 10 19:32:46 iZ94r80gdghZ mysqld[14771]: 2016-04-10 19:32:46 14005736395....
4 月 10 19:32:46 iZ94r80gdghZ mysqld[14771]: Version: '10.1.13-MariaDB'  soc...r
4 月 10 19:32:46 iZ94r80gdghZ mysqld[14771]: 2016-04-10 19:32:46 14005736351...s
4 月 10 19:32:46 iZ94r80gdghZ mysqld[14771]: 2016-04-10 19:32:46 14005658500....
4 月 10 19:32:46 iZ94r80gdghZ mysqld[14771]: 2016-04-10 19:32:46 14005736351....
4 月 10 19:32:47 iZ94r80gdghZ mysqld[14771]: 2016-04-10 19:32:47 14005736351...2
4 月 10 19:32:47 iZ94r80gdghZ mysqld[14771]: 2016-04-10 19:32:47 14005736351...e
4 月 10 19:32:47 iZ94r80gdghZ systemd[1]: Failed to start MariaDB database s....
4 月 10 19:32:47 iZ94r80gdghZ systemd[1]: Unit mariadb.service entered faile....
4 月 10 19:32:47 iZ94r80gdghZ systemd[1]: mariadb.service failed.

那么根据如上提示怎么定位数据库出错原因呢？