Identifying which rails app is using the most memory on a box?

Question

We have several rails apps using passenger and apache on some ubuntu servers that get heavy load occasionally. We get datadog alerts that memory usage is high, get on the server, and do a top to see that passenger and ruby are using lots of memory, but how should I go about figuring out which one of the passenger/rails apps is the culprit? Or at least a list of apps using above a given threshold of memory?

Answer 1

I have only one RoR running on my server (and it's nginx) and I think your looking for

ps auxf

it shows me this for my one passenger instance:

nginx 28279 0.0 10.2 452128 107264 ? Sl Apr03 0:01 Passenger RackApp: /srv/http/redmine

The third column (10.2) is memory usage in %, the last columns shows the directory to the application. More about output here.