Given a string containing a directory, this function will return the number of bytes available on the corresponding filesystem or disk partition.
A directory of the filesystem or disk partition.
Given a file name instead of a directory, the behaviour of the function is unspecified and may differ between operating systems and PHP versions.
// $df contains the number of bytes available on "/"
$df = disk_free_space("/");
// On Windows:
This function will not work on remote files as the file to be examined must be accessible via the servers filesystem.