Q:

Server performance upgrade for 500 users

I have an application(Moodle platform) with 50 users. 
The actual performances of the server are:

RAM is 2 GB
Storage is 10 GB
CPU is AMD 2.1 GHz with 2 Core

The server is hosted in amazon, instance type t3a.small
The actual status of usage of RAM and Storage are:

RAM 1.8GB
Storage 8.9GB
CPU

My plan is to have 500 users soon what should I upgrade from those performances? 

A:

You need to have 4-5 checkpoints and measure your stats.  Say 1 user, 5 users, 10 users, 25 and 50 users.  If you’ll see simple dependency you can estimate would 500 users fit in or how many gigs of RAM you need to throw in to make everyone happy.