无法重启mysql

Question

我的 WordPress 网站由 DigitalOcean 托管，我收到了 Error establishing a database connection。所以我检查了数据库出了什么问题。

sudo /etc/init.d/mysql restart 返回

stop: Unknown instance: 
start: Job failed to start

df -h /返回如下，说明磁盘未满？

Filesystem                 Size  Used Avail Use% Mounted on
/dev/disk/by-label/DOROOT   20G   12G  6.9G  63% /

sudo -u mysql mysqld 返回

170828  4:33:48 [Warning] Using unique option prefix key_buffer instead of key_buffer_size is deprecated and will be removed in a future release. Please use the full name instead.
170828  4:33:48 [Note] mysqld (mysqld 5.5.52-0ubuntu0.14.04.1) starting as process 18825 ...

mysqld 返回

170828  4:34:17 [Warning] Using unique option prefix key_buffer instead of key_buffer_size is deprecated and will be removed in a future release. Please use the full name instead.
170828  4:34:17 [Note] mysqld (mysqld 5.5.52-0ubuntu0.14.04.1) starting as process 18866 ...
170828  4:34:17 [Warning] Can't create test file /var/lib/mysql/chengtie.lower-test
170828  4:34:17 [Warning] Can't create test file /var/lib/mysql/chengtie.lower-test
mysqld: Can't change dir to '/var/lib/mysql/' (Errcode: 13)
170828  4:34:17 [ERROR] Aborting

170828  4:34:17 [Note] mysqld: Shutdown complete

那么有谁知道mysql有什么问题吗？怎么重启？

编辑 1： 我注意到/var/lib/mysql/phpmyadmin 下没有config.inc.php 或config.sample.inc.php。

Answer 1

你看过这个帖子吗：Ubuntu - 12.04 - MySql won't start by using service mysql start

你可以试试

mysqld --verbose

获取更多信息

Answer 2

mysqld: 无法将 dir 更改为 '/var/lib/mysql/' (Errcode: 13)

那是“权限”。我怀疑 MySQL 是作为 root 以外的其他用户安装的。建议您重新安装（以 root 身份），尤其是在您还没有任何数据的情况下。

Answer 3

似乎 /var/lib/mysql/ 存在权限问题

https://dba.stackexchange.com/a/106135 可以解决。

Answer 4

define('DB_HOST', 'localhost'); 不应该是 'localhost'，它应该是 mysql 服务器主机名。