Node cluster versus Dynos scaling

Question

After reading a handful of articles on scaling node apps I have not yet made up my mind about when should I use node builtin cluster or simply adding more dynos.

Let me tell you I have already read the following threads on StackOverflow:

How to properly scale nodejs app on heroku using clusters

Running Node.js App with cluster module is meaningless in Heroku?

As far as I understood it, if I make use of node cluster functionality I will end up with the total memory available divided by the number of forked processes.

On the other hand, if I add one more dyno I will double the memory available.

So, what is the point of using node clusters?

Answer 1

It's not really an either-or situation. You can make use of multiple node cluster instances on multiple dynos. Memory isn't really what you want to look at, though, since that would be a shared resource. CPU / core usage is more relevant to clustering in node, since each node process can only make use of one CPU core at a time.

It's really going to depend on which dynos you are using, too.

Have you seen these suggestions on the official heroku docs yet?