FMS' limits

Well... it really depends on the machine fms is running on, the internet pipe it's connected to, and the bitrate of the streams you're serving.

Let's assume you're running a fairly powerful machine (maybe a dual Xeon, 4meg machine), you have a 100mbps pipe, and your streams are set at 256kbps.

In this case, you'd max out the internet pipe at about 400 concurrent streams... far fewer than the server can handle. I've read that FMS can handle several throusand concurrent live streams on a single box, but I've never pushed it that hard (the most I've has on a single box was about 1000)

You can limit the number of allowed connections at the server level by modifying your vhost.xml file for the vhost you want to limit, or you can do it at the application level by checking connected clients in your application.onConnect method:

application.onConnect = function(clientObj){
if (application.clients.length > 10){
// Execute code to reject connection (too many users)
}else{
// Not too many users, accept the connection or execute other code
}
}

Now, FMS has no means of redirecting the client to another server, but you can put that logic in the client side.

As for shared hosts, I've never used any of them, but Ive heard good things about influxis (although the cost adds up fast if you want to handle more than a few concurrent users)

Others:
mediatemple.com
akamai.com
moremx.com