Slow initialization of rails 3.1 applications on nginx/passenger

Question

I have started learning and developing web applications with Rails 3.1.

I have 3 applications hosted on a "webby" by webbynode.com and I am using their webby gem. Everything is going fairly ok except for one or two little things:

Whenever I push to the webbynode server the update of one of my apps, everything goes well, but the initialization of each of the three websites is really slow. Is this normal ( that all applications need to be reinitialized, even if only one has been updated)?

Also, after a while if the websites don't get any visits ( and they don't get too many of them...), it seems that the server shuts down, and again each website takes ages to be reinitialized at the next visit.

I understand it might be coming from "spawners", I was just wondering if someone could explain quickly why the server seems to go to sleep and/or point me to suitable settings for NGINX?

Thanks a lot!