I am deploying a rails application on EC2 instances, where I want to configure Auto Scaling to be used with an Elastic Load Balancer. On a particular threshold I want to spawn a new instance. While configuring trigger for auto scaling group, we have options for CPU Utilization, Network or disk IO; but being a rails application, I will face resource crunch on memory rather than CPU or IO.
Has anyone configured EC2 Auto Scaling for a rails application successfully? What is the preferred way of using AWS with rails?
FYI: I am using passenger as application server.
Thanks for your time.