各位好，我的 CentOS 7 系統碟切分的很小，資料庫資料日益肥大快撐不住了，所以要更換資料儲存位置，參考了這一篇文章 How To Change a MariaDB Data Directory to a New Location on CentOS 7。

我先開了一台 Centos 7 的虛機做實驗，執行步驟如下：

service mariadb stop
mkdir /data/
rsync -avh /var/lib/mysql/ /data/
mv /var/lib/mysql /var/lib/mysql_bk
chown mysql:mysql -R /data

修改 /etc/my.cnf。

[mysqld]
datadir=/data/
socket=/data/mysql.sock

[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid

[client]
port=3306
socket=/data/mysql.sock

# include all files from the config directory
!includedir /etc/my.cnf.d

然後執行啟動。

service mariadb start

得到錯誤資訊。

Job for mariadb.service failed because the control process exited with error code. See "systemctl status mariadb.service" and "journalctl -xe" for details.

查看 mariadb.log 後得到。

230216 02:37:46 mysqld_safe Starting mysqld daemon with databases from /data/
230216  2:37:46 [Note] /usr/libexec/mysqld (mysqld 5.5.68-MariaDB) starting as process 6016 ...
230216  2:37:46 [Warning] Can't create test file /data/localhost.lower-test
230216  2:37:46 InnoDB: The InnoDB memory heap is disabled
230216  2:37:46 InnoDB: Mutexes and rw_locks use GCC atomic builtins
230216  2:37:46 InnoDB: Compressed tables use zlib 1.2.7
230216  2:37:46 InnoDB: Using Linux native AIO
230216  2:37:46 InnoDB: Initializing buffer pool, size = 128.0M
230216  2:37:46 InnoDB: Completed initialization of buffer pool
230216  2:37:46  InnoDB: Operating system error number 13 in a file operation.
InnoDB: The error means mysqld does not have the access rights to
InnoDB: the directory.
InnoDB: File name ./ibdata1
InnoDB: File operation call: 'open'.
InnoDB: Cannot continue operation.
230216 02:37:46 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended

即便我把 /data/ 的權限設定為 777 都一樣得到沒有權限的資訊，不知道是哪邊出了問題。