What is the maximum number of HTTP connections I can open in a single Windows Server 2008 window?

Question

I have a web server that hosts an HTTP chat application that works with a long poll.

This means that the client browser "polls" for new information, and the server does not respond until there is information to send, so the HTTP connection remains open for a long time, up to a minute.

My question is how many of these connections the server can handle open at the same time before it dies.
Of course, there is no exact number, but I want to understand an order of magnitude (1000, 10 000, 100 000?)

Any ideas related to this, based on any experience you may have, are more than welcome!

Answer 1

I found this:

http://blogs.msdn.com/david.wang/archive/2006/04/12/HOWTO-Maximize-the-Number-of-Concurrent-Connections-to-IIS6.aspx

To give a sense of scope - I have seen 50K + simultaneous connections to IIS6 on WS03SP1 x64 with 4 GB RAM.

Anything else you can find?

Answer 2

Honestly, in all but the most extreme situations, you will have a lack of resources for your application before you exceed the number of supported connections. IIS can handle a crazy amount of clean network connections, but ultimately it comes down to the fact that your application can quickly process data from them.

If you really expect to scale it to thousands of users at the same time, I would go further and build in your project to be able to scale to several interface servers. Most likely, it will look like a load balancer or reverse proxy server that balances these HTTP connections between external servers, and these front-end servers process and exchange data with the central SQL database or some other storage mechanism.

Edit: Another point regarding a single server scenario is that no matter how many IIS connections it can handle, your firewall also has its limits. This is usually also a crazy amount, but you also need to look at your firewall if you really want to find the ceiling.