Thanks, so deploying mongodb in other instance with more storage volumes will work?

Bill , We have our user base ready, and expecting around 25k regular users by the end of this December.

Thanks for that article. As you said that we shouldn't use node for heavy calculations, but we are sending bulk sms, email, bill generation(for more than 2k-2.5k users in one set and there may be n number of sets running at a time). Now as I have already added Cluster, NGINX(at 3000), PM2, NSP do i need to worry about this task or I should change this calculations to other module/port/node or some other platform? One thing more, my project is running on a single port and module, how can I increase no. of ports and module (if I should) without changing much of the codes in my project? P.S.: We are using aws n2.micro free tier, mongoDB in same ec2 instance. Userbase is already created so expecting more than 25k downloads by December. Is there anything more I should be concerned about? Thanks in advance.