phpcms备份不了数据库文件

chmod 644 /path/to/database/file
chown www-data:www-data /path/to/database/file

$db_host = 'localhost';
$db_user = 'username';
$db_pass = 'password';
$db_name = 'database_name';

df -h /path/to/backup/directory

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检测连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}
echo "连接成功";
?>

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检测连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 备份数据库
$backup_file = "/path/to/backup/directory/" . $dbname . "_backup_" . date("Y-m-d_H-i-s") . ".sql";
$command = "mysqldump -h $servername -u $username -p$password $dbname > $backup_file";
exec($command, $output, $return_var);

if ($return_var == 0) {
    echo "数据库备份成功: " . $backup_file;
} else {
    echo "数据库备份失败";
}

$conn->close();
?>