Web Hosting Talk : Web Hosting Main Forums : Dedicated Server : calculate bw needs

[dhecker]

I am getting ready to sign up with Rackspace to host an application I'm about to release. It's an online workflow tool (www.worldwideworkbench.com) that mainly consists of a php/mysql app that people use to manage projects.

So, it's mainly people looking at forms, filling in or reading data, then clicking to the next similar page. Not unlike a forum in that the site will be very text heavy, and almost all images will be cached by the browser early on, with the exception of the occasional uploaded image.

My question is: How do I determine how much bandwidth I need? Rackspace is a killer once you exceed the 30g limit, and I'm really not sure how this kind of thing goes.

I can guess, but is there any METHOD or metrics for this? It would be great to know how much THIS site uses, for example. If anyone has any busy websites that I can use for comparison, that would be really helpful.

thanks,
dh

[sholden]

Run the software internally (which I assume you are already doing for development/testing purposes) and have a few people (or just one in a pinch) use it a bit.

Using it as you expect a normal user would - not as a tester would. Record the traffic generated (by checking log files, or by looking at the traffic over the NIC if the machine is doing *nothing* else).

Then estimate how often (and/or for how long) the average user will use the software each month.

Multilpy the numbers.

You can either estimate how many users you will have and hence how much traffic you will generate. Or you could factor that bandwidth cost into your pricing to the user so that if you have between N and M users the hosting costs are covered (assumming you charge of course, if you fund via advertising or something then you can work out bandwidth per page view (and hence ad impressions) and determine if it is sustainable).

Of course you will have heavy and light users, so running a test trying to simulate a heavy user will also let you know how much risk there is in going over the estimated bandwidth. If a heavy user generated twice as much traffic as a normal user you would expect to be safe. However, if one heavy user can generate hundreds of times the traffic of a normal user it becomes a bit dicy - see "unlimited traffic" hosts for an example.