Ruby on Rails stuff seems to assume you'll need to do significant sysadmin work. I've intentionally avoiding doing much of that for awhile... and it's really time for me to learn. So I've figured out basic SQL and MySQL, database creation and backup, simple app deployment. Now I'm sifting through firewall and DNS stuff. We'll see how much of this I actually stick with, but so far, so good.
And I'd never looked into a lot of how you, y'know, actually stick an app on the web. MemcacheD, caching proxies, reverse proxying with Apache and NGinX, clustering, load-balancing, all kinds of database optimization... Wow. There's really a lot to it. We'll see how much of it I actually learn and/or use, but I've learned the basics of it, at least, so I could really dig into it if I needed to.
And while reading many, many web sites on all of these topics and many more, I'm again struck by the differences between web and print. There's a lot of web documentation that is simply not available in print, and which is absolutely worth the time. However, really serious in-depth documentation on how to do something complicated just works better in a book, and web sites are rarely available on those topics. To learn to do some specific, small task in Ruby on Rails, the web is the way to go. To learn the basics of Rails overall, somehow all those many, many web doc sites still miss most of what's in the basic Rails book.