Number of connections meteor can handle

how many connections can a non realtime meteor app can handle on 1GB VPS.

This depends a lot on how your site is structured and what your users are doing

it will be a kind of q and a forum where users have functionality to write posts

It still depends.

For example, if you build from meteor --minimal, there’s no Mongo or DDP (so no reactivity). That gives you a Meteor app with more “traditional” Node REST app performance (maybe several thousand simultaneous users).

If you want to use reactivity and Mongo (traditional Meteor), then it’s really down to how well you can architect your app to minimise impact on the server. Perhaps several hundred simultaneous users if you do it well.