We’re hearing this from multiple sources: After nearly two years of high profile scaling problems, Twitter is planning to abandon Ruby on Rails as their web framework and start from scratch with PHP or Java (another solution is to stick with the Ruby language and move away from the Rails framework).
Former Chief Architect Blaine Cook famously said scaling Rails was “easy” in April 2007 (see image to right), but problems persisted after Cook claimed to have conquered the problem. The service most recently had a three day outage affecting their largest users.
Switching off Rails may not solve all of Twitter’s problems. They have nearly two years of infrastructure built up and would face many more growing pains if they switched frameworks or rolled their own. As Twitter considers moving away from Rails, some companies are doing the opposite: last year, Yellowpages.com scrapped Java for Rails, and is now second on the unofficial Rails 100 wiki.
Rails has always bred controversy. Developers have argued that it is fundamentally flawed and unscalable; others have argued back saying the opposite (see here, here, and here). Earlier this year, one of the core community members and creator of the popular Rails web server Mongrel abandoned rails and trashed the community.
Update: Regarding Evan Williams’ statement here, all I can say is that multiple sources claim that Twitter is telling people they are planning on moving away from Ruby on Rails. This is not the first time a company has denied something that has turned out to be 100% true.