CodeIgniter load capacity?

Hi!

I'm building a large website on a scalable server and I'm thinking of using CodeIgniter   . The only thing is, I'm expecting a LOT of traffic in the first few days. How does CI handle large loads? Will users be blocked when trying to reach the server during high-traffic times?

As a side-note, what does CI offer in terms of scalability and stability that other frameworks lack?

Thanks in advance for all your answers!