I have some mixed feelings about the integration of Merb and Rails because Merb is a small "micro kernel" type framework that seems just about perfect for projects like light weight web services and web portals. On the good side of this merger: if Rails becomes more modular and the resulting Rails 3.0 can also be tailored down to 'just what is needed', then this merge should end up being good for developers. I have just signed a publishing contract for a new Ruby book that has one part on publishing information for consumption by both humans and software agents. After waiting a few months, I will grab early Rails 3.0 builds and write to Rails 3.0. A bit funny because before my holiday break I was deciding whether to use Merb or Rails for this book example.

I am re-writing a quick one or two evening hack from 3 years ago ( RubyPlanet.net ) in Ruby + Merb. I originally wrote this web site in Java - humorous since it is a Ruby blog feed aggregator :-) I am also using this as the example program for a DevX article on Merb that I am working on. I just did a very quick first cut at the example program for the article (i.e., what soon will be the new RubyPlanet.net) and without doing any caching and hitting a database a lot, I was surprised to see that ab -n 5 http://localhost:4000/ showed 44 page requests per second. My goal is to get 100 to 200 page requests handled per second (depending on the number of blog entries on the main page) using a single process on my MacBook, and that looks like it may be easy. Deployed on a very low cost VPS with a bunch of other applications, this web app may not be all that fast "out in the field" but I want that to be a limitation of the server, not the code.

I am back home after attending MerbCamp in San Diego last weekend. Merb is sort of like a micro-kernel architecture version of Rails: a small core with many plugins (and also complete "slice" mini-apps) that (hopefully) do not depend on each other. The idea is that you only add in what you need. Right now is probably not the time to try Merb for the first time: the developers are working right now to release version 1.0 RC1 (with version 1.0 to follow as quickly as possible). I am currently using Merb 0.9.9 and I am not going to update until I can do a "gem update merb" to move up to the 1.0 APIs. As announced at MerbCamp, the developers want to stabilize the APIs for version 1.0 and then continually work with minor 1.x releases for about one year, then release 2.0 that is likely to not be very backwards compatible with 1.0. Also, 1.x releases will be backwards compatible with 1.0 but not necessarily other 1.y releases. I think that this is a good plan, and matches ...

I am at MerbCamp - so far an enjoyable conference. Merb is a more modular and more efficient version of Rails. As you might expect, Merb does not yet have the easy 'out of the box' experience that Rails provides. That said, I will probably start to use Merb instead of Rails on some new projects because of performance (run time and much less memory required) reasons.