php backup mysql

function backup_tables($host,$user,$pass,$name)
{
    $link = mysql_connect($host,$user,$pass);
    mysql_select_db($name,$link);
    mysql_query("SET NAMES utf8");
   
    $backupFile = $name . date("Y-m-d-H-i-s") . '.gz';
    $command = "mysqldump --opt --host=$host --user=$user --password=$pass $name | gzip > $backupFile";
    system($command);
   
    mysql_close($link);
}