Might as well start off this week by getting people's blood boiling. According to a comment on Dion's blog:
Having done extensive performance (scalability means different things to different people) testing on both Rails and a comparable Spring/Hibernate/JSP2 webapp (no one seems have have done any sort of benchmarking on Rails, or they simply don't care, I don't really know, but since benchmarking is what I do... ) I can say that Apache2/FastCGI/Rails is about... 8x slower than the comparable Tomcat/Spring/Hibernate/JSP2 solution. And that is with caching turned on in Rails (using Rails 0.9.5...)
Quite frankly, 62 req/s on a Dual Opteron with 4GB of RAM rendering a simple view with no DB access is too... damn slow.
Personally, I still think Rails looks like a great (and easy) way to develop webapps. I just wonder if there's some truth to the "can't scale" argument. I guess the best way to find out is for me to develop an application like AppFuse with Rails, and then hammer it (and AppFuse) with JMeter to see what kind of results I get.
On a sidenote, I wonder when Rails will hit the illustrious version 1.0? They released 0.1 last week - which is a bad version number for marketing. If it's as mature as folks claim, why not make the next release 1.0? That version number alone will likely allow developers to use it more in big companies.