[bradleyland]

Running different versions of Ruby on a single server requires a lot of attention to detail. I used to do it, but I didn't use an automated tool like RVM. RVM is great for switching environments, but it is unnecessary when all you need are a static set of environments that change infrequently. Check out ruby-build for this purpose.

In the end, I found the trouble of running two reliable Ruby environments in production did not offset well against the cost of either updating applications to work with the same Ruby version, or running separate virtualized environments at the OS layer. The time spent debugging and updating our environment was too great in comparison to the additional cost of upgrading our software to all run on Ruby 1.9.