dd if=/dev/urandom of=speedtest_file.bin bs=1G count=1// твои данные тут
$input = json_decode(file_get_contents("php://input"), true);location / {
proxy_pass http://server/;
proxy_intercept_errors on;
proxy_redirect off;
error_page 502 /502.html;
}
location /502.html {
root /path/to/directory/with/error/pages;
}