The purpose of the ssl_stapling_file was to prime the cache. Without that file, openssl says "OCSP response: no response sent". For nginx to load the cache by itself, clients have to hit the same worker process a few times. I currently have 8 worker processes, which means that the server needs at least 8 simultaneous client who are knowledgeable and patient enough to hit the server a few times, purging the cache of their browser each time. This does not work seem to work all the times, however. I have a www to non-www redirection with stapling enabled on both. Hitting www does not fill the cache, and I keep seeing "OCSP response: no response sent". Am I missing something?