Run multiple instances of your hub behind a Load Balancer .
Use Socket.io (Node.js) or SignalR (.NET). This creates a "persistent pipe" between the hub and the users.
This second part of our series dives into the of your server-side hub. If Part 1 was about setting the stage (infrastructure and basic routing), Part 2 is about making the gears turn—handling data persistence, real-time synchronization, and security.