My experiences with the book, so far...

First off, the books definitely worth getting. I’ve got several young rails apps in production and am hoping to keep them moving snappily, taking Ezra’s advice.

1) Benchmarking performance.
I built an almost-empty rails app and ran ab -n 1000 <URL> against it. The results were frighteningly bad … roughly 27 requests per second. I was about to file a ticket with my hosting provider when I realized I’d started up the emtpy rails app in development. Switch to production and I’m up above 200 requests per sec. A happy moment.

2) Setting up SSH.
I switched my SSH port from 22 (default) to a higher number.
This required a change to my capistrano deploy.rb scripts.

ssh_options[:port] = '<port-number>'

This should probably be noted in the book.

3) Also regarding SSH…
Following the book’s advice, I disallowed root logins on the server. Several of my capistrano scripts – notably, grabbing a mysqldump and importing it into the dev db – had to be tweaked to use sudo.

I also took the books advice on changing my ssh port, but had to use google to find the ssh_options[:port] thing.