如何在PHP中下载大文件（> 250 MB）？

Question

I have a script that allow user to download file with filesize > 250MB. When the filesize is < 100MB, it's downloadable. But not with file > 250 MB.

I have changed the setting in php.ini:
memory_limit = 12800M
post_max_size = 8000M
upload_max_filesize = 2000M
max_execution_time = 512000 

But still it's not workable. How to make it so that i can download file with > 250MB ?

Update: code to download the zip file

ini_set('max_execution_time', 512000);

$file_folder = "image/data/";   // folder to load files

$zip = new ZipArchive();            // Load zip library 
$zip_name = "image.zip";            // Zip name
if($zip->open($zip_name, ZIPARCHIVE::CREATE)!==TRUE){       // Opening zip file to load files
    echo  "* Sorry ZIP creation failed at this time<br/>";
}

$dir = opendir ("image/data");
$counter = 0;
while (false !== ($file = readdir($dir))) 
{
    if($file == '.' || $file == '..')
    {   }else
    {
        $zip->addFile($file_folder.$file, $file);
    }
}

$zip->close();

// push to download the zip
header('Content-type: application/zip');
header('Content-Disposition: attachment; filename="'.$zip_name.'"');
header('Content-Length: ' . filesize($zip_name));
readfile($zip_name);
// remove zip file is exists in temp path
unlink($zip_name);

Answer 1

Ok..so now i can get my file to be downloaded. But, once i want to extract the zip file, error msg is given, saying that: The archive is either in unknown format or damaged. I check the copy of the zip file in the original folder n try to extract, it works fine. No problem in extracting the data. Below is the script:

set_time_limit(0);
$file_folder = "image/data/";

$zip = new ZipArchive();    // Load zip library 
$zip_name = "image.zip";             // Zip name
if($zip->open($zip_name, ZIPARCHIVE::CREATE)!==TRUE){       // Opening zip file to load files
    echo  "* Sorry ZIP creation failed at this time<br/>";
}

$dir = opendir ("image/data");
$counter = 0;
while (false !== ($file = readdir($dir))) 
{
    if($file == '.' || $file == '..')
    {   }else
    {
        $zip->addFile($file_folder.$file, $file);
    }
}

$zip->close();
if(file_exists($zip_name)){

    // set headers push to download the zip
    header("Pragma: public");
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Cache-Control: public");
    header('Content-type: application/zip');
    header("Content-Transfer-Encoding: Binary");
    header('Content-Disposition: attachment; filename="'.$zip_name.'"');
    header("Content-Length: ".filesize($zip_name)); 

    //readfile($zip_name);
    // remove zip file is exists in temp path
    //unlink($zip_name);

    $fp = @fopen($zip_name, "rb");
    if ($fp) {
     while(!feof($fp)) {
         echo fread($fp, 1024);
         flush(); // this is essential for large downloads
         if (connection_status()!=0) {
             @fclose($zip_name);
             die();
         }
     }
     @fclose($zip_name);
    }
    unlink($zip_name);
}

the File size that I retrieve is also correct. What is the problem?