Testing maximum client connections

I need to test the maximum theoretical and maximum feasable connections a server program can handle. Any suggestions on doing this?

keep connecting clients until performance degrades below desired threshold (as defined by "feasible"), then keep adding clients until the server crashes (theoretical) ?

well, I suppose I will need a couple more systems then, otherwise client load will interfere with server load.

also depends on what method is used for multiple client handling! a less efficient method will crash with small number of connections!

Yeah, well my code is usually pretty efficient. I'm aiming at a minimum of 1024 connections per server.

What are you doing for multiple clients?

- thread spawning?
- OR thread pool?
- select ?

I also wonder what should we do, besides having powerful server, to handle millions of clients? :(

Generally large numbers of clients are handled by multiple servers. When a server reaches its limit for example, it can forward additional connections to a different server in the cluster or simply refuse the connection adn the lcient can pick the next server in a list.