What exactly determines how many users can connect to a site at once?

[whadu]

I'm still not certain what exactly determines how many users you can have connected to your site all at once; I know it depends on a various amount of things, but I'm wondering what is most important. Is it the amount of RAM, or something else?

If I wanted to allow more people to connect at once, what should I increase or what hardware should be added?

Thanks in advance for any replies.

[carguy84]

In the database world, it is set with the database. SQL Server defaults to 100 simultaneous, open connections.

Your web server can also have a limit set and will start throwing server too busy errors.

CPU will be the first hardware part to be maxed out serving web pages.

[phranque]

welcome to WebmasterWorld [webmasterworld.com], whadu!

there is not a simple answer to those questions.
there can be limits to the number of incoming connections a server can have, the number of processes the server can spawn, the number of simultaneous db connections, the memory available, etc. (as well as softer limits such as bandwidth, disk throughput, processor speed, etc.)

[dailypress]

100 simultaneous? how does that work if you have over 50,000 unique visitors/day? Can you increase the 100 limitation?

[LifeinAsia]

Not sure where you're getting that number- the default SQL Server setup is 32,767 concurrent connections.

[carguy84]

*sorry, I meant ADO, not SQL. And yes, you can increase the number of open connections in ADO, but you shouldn't have to. Each connection is only open (if coded correctly) for milliseconds.