Configuring error log in /etc/my.cnf in [mysqld] is not took into account.

[Code]

# The following options will be passed to all MariaDB clients
[client]
# password  = your_password
# port       = 3306
# socket     = /var/run/mysql/mysql.sock

[mysqld]

# Remove leading # if you don't want to listen on network (only socket - safer)
# skip-networking
.....
.....
log-error         = /var/log/mysql/mysql/mysql_error.log
.....
.....

[/Code]

You have to modify /usr/lib/mysql/mysql-systemd-helper this way :

[Code]
mysql_start() {

    exec /usr/sbin/mysqld \
        --defaults-file="$config" \
        $ignore_db_dir \
        --user="$mysql_daemon_user" \
        --log-error="/var/log/mysql/mysql/mysql_error.log"
}
[/Code]

Changing the syntax in /etc/my.cnf
from log-error=
to
log_error=
make no difference.

Note:
-----
In /etc/my.cnf setting general log run ok :
[Code]

# The following options will be passed to all MariaDB clients
[client]
# password  = your_password
# port       = 3306
# socket     = /var/run/mysql/mysql.sock

[mysqld]

# Remove leading # if you don't want to listen on network (only socket - safer)
# skip-networking
.....
.....
general_log       = 1
general_log_file  = /var/log/mysql/mysql/mysql.log
.....
.....
[/Code]

To verify the mysql configuration I use this command :
[Code]
mysql --socket=/var/run/mysql/mysql.sock  -BNe "show global variables" | grep
err[/Code]
and
[Code]
mysql --socket=/var/run/mysql/mysql.sock  -BNe "show global variables" | grep
general_log[/Code]