Here’s what Heroku says about dyno memory usage:
Dynos are available in 1X or 2X sizes and are allocated 512MB or 1024MB respectively.
Dynos whose processes exceed their memory quota are identified by an R14 error in the logs. This doesn’t terminate the process, but it does warn of deteriorating application conditions: memory used above quota will swap out to disk, which substantially degrades dyno performance.
If the memory size keeps growing until it reaches three times its quota, the dyno manager will restart your dyno with an R15 error.
SUMMARY: This is a step-by-step overview of how to get Oink installed in your Rails app on Heroku, and use it to analyze your memory usage. Starts with a brief description of the problem space, skip down if you just want to get on with your Oink integration.
My stack includes these technologies: Rails 3, Unicorn, NewRelic, Heroku, Hodel3000CompliantLogger, and now Oink.
Why is understanding memory usage important? For me, it’s because Heroku routes traffic to my dynos randomly.