If you get an error like “Unknown variable default character set utf8” MySQL or MariaDB 5.5 in /var/log/mariadb/mariadb.log when I restart MySQL database, you can resolve this problem with change variable name. Error You can look for error /var/log/mariadb/mariadb.log /usr/libexec/mysqld: unknown variable ‘default-character-set=utf8’ Aborting Solution