Yes. I was on a call with a couple of the twitter devs around this time. They were running on 30 odd instances at joyent. So while they were decent size, they w

Yes. I was on a call with a couple of the twitter devs around this time. They were running on 30 odd instances at joyent. So while they were decent size, they were nothing like they are now. Mongrel was always pretty solid actually. It was originally developed for verisign as I recall, and even in its early versions stuck much more closely to the http specs than other webservers. It caught a lot of flack because of application code blasting out the ruby heap by touching too many objects. Mongrel isn't really to blame for that. With early versions of ActiveRecord it was easy to materialize large result sets without realizing it. A lot of people felt the pain of using associations everywhere without thinking about what would happen when the joins would go north of 10k objects. Not really mongrel's fault.