Zero downtime deploys

I'm getting an issue when doing zero downtime deploys as outlined here: http://railscasts.com/episodes/373-zero-downtime-deployment

It seems that and new gems aren't getting loaded, do I need a similar fix to this| but for mina? http://railscasts.com/episodes/373-zero-downtime-deployment?view=comments#comment_162038

[phuongnd08]

How is that related to mina? Zero downtime should have something to do with your server. If you use unicorn, for example, there shall be a handful of configuration allow unicorn not to quit the current web worker until the new web worker has been spinned up.