We could use advice on a scaling/ops issue.
We have a simple mobile app that runs on Rails 3.2.12 and uses MongoMapper instead of ActiveRecord. There is one database call that sporadically performs poorly, causing users to write in and complain. It isn't clear why. We can't install NewRelic because of MongoMapper, and the data returned by Mongo isn't a lot. There isn't much logic being executed in the controller, either.
One potential explanation is that we use a VPS shared with 30 nodes. The hosting company, RailsPlayground, says the machine's average I/O utilization is only 12% but can't provide more extensive stats (e.g., peak I/O utilization).
The question: would moving to a dedicated server help? I realize this is difficult to answer, but any general thoughts/advice would be appreciated.