应该如何设置针对高需求应用程序的node.js堆栈？

I'm currently working on a Node.js stack application used by over 25000 people, we're using Sails.js framework in particular and we got MongoDB Application is running at a EC2 instance with 30GB of RAM, databse is running on a Mongolab AWS based cluster in same zone the EC2 is. We even got an Elastic Cache Redis instance with 1.5GB for storage.I'm currently working on a Node.js stack applic