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4 Effective Methods to Get Directory Disk Size in PHP

M66 2025-07-26

How to Get the Total Disk Size of a Directory in PHP

In web development, there are situations where you need to determine how much disk space a specific directory (and its subdirectories) is using—for example, for storage limits, usage reporting, or monitoring logs. PHP provides several built-in functions that can help calculate directory disk usage effectively.

Using disk_total_space to Get Total Disk Capacity

The disk_total_space() function returns the total space of the entire disk, not just the directory. It’s useful when you want to know the full capacity of the disk where the directory resides.


$directory = "/var/log";
$total_space = disk_total_space($directory);
echo "Total disk capacity: $total_space bytes";

Using dir() and filesize() to Sum File Sizes

You can iterate through the directory using opendir() and use filesize() to accumulate the size of each file. This gives a more accurate measurement of actual disk usage for that directory.


$directory = "/var/log";
$total_size = 0;
if ($dh = opendir($directory)) {
    while (($file = readdir($dh)) !== false) {
        if ($file != "." && $file != "..") {
            $total_size += filesize($directory . "/" . $file);
        }
    }
    closedir($dh);
}
echo "Total disk usage: $total_size bytes";

Using RecursiveIteratorIterator to Traverse Directories

To recursively scan a directory and its subdirectories, use RecursiveDirectoryIterator with RecursiveIteratorIterator. This method is ideal for deep directory structures.


use RecursiveIteratorIterator;
use RecursiveDirectoryIterator;
use SplFileInfo;

$directory = "/var/log";
$total_size = 0;
$iterator = new RecursiveIteratorIterator(
    new RecursiveDirectoryIterator($directory),
    RecursiveIteratorIterator::SELF_FIRST
);

foreach ($iterator as $file) {
    if ($file->isFile()) {
        $total_size += $file->getSize();
    }
}
echo "Total disk usage: $total_size bytes";

Using scandir() and array_sum() for a Simple Calculation

scandir() returns the file list in a directory. Combined with array_map() and array_sum(), this approach provides a concise way to calculate size, though it doesn’t work recursively.


$directory = "/var/log";
$files = scandir($directory);
$total_size = array_sum(array_map("filesize", array_filter(
    array_map(function($file) use ($directory) {
        return $directory . '/' . $file;
    }, $files),
    function($file) {
        return is_file($file);
    }
)));
echo "Total disk usage: $total_size bytes";

Performance Tips

  • Recursive iterators are generally more efficient and reliable for large or nested directories.
  • Avoid using glob() for large datasets—it’s slower and consumes more memory.
  • If you need to check directory size frequently, consider implementing a caching mechanism to store the result.

Conclusion

PHP provides multiple approaches to calculate the disk size used by a directory. Choose the method that best fits your application’s needs. Efficient implementation and selecting the right functions can result in accurate and fast disk usage reporting.

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