This is probably a stupid and vague question, but say for example i rent the following:

Intel Celeron 2.4GHz
512MB RAM
Fedora OS
10mbps Connection

Ignoring Monthly Traffic and Hard Drive constraints, roughly how many Web Servers could you run off the above server because it starts to lose performance and basically turns crap...?

Obviously it will differ depending on how often a specific website is accessed, or the material running off it and MySQL Databases...but just an estimate would be good.

Thanks

Daniel, there is no way to give an estimate like that. It will vary so much by your customers, the sites, etc..

If they were all static sites, no dynamic material, you could run over 1,000, but that isn't how the world works.

Basically you have to expect a mix of sites. You could run anywhere from 100 to 1,000 depending, but you also have to figure in your ROI and how many sites you need on the server to make a profit.

1000 low traffic websites, maybe 2-5 high traffic websites.

You really have to take into account what types of sites are running on the server.
There really isn't an "average website" anymore. If an average site is just 25 pages of flat html, I've seen a P4, 1gb ram run over 2000 sites, and still perform very well. (Aside from dns issues from cPanel.)

Another question, what will the server be running? OS, Webserver, modules, etc?

If you did have to pin down "average" sites to be what you get with a random sample of clients, I'd put no more than 100 on a box like that, and probably many less. Frankly, it's been so long since we hosted on single celerons, I can't really remember how good or bad the performance was, but it seems like 100 is max.

The advantage of using higher-end hardware with dual / quad procs is the fact that you get a bit closer to the law of large numbers (http://en.wikipedia.org/wiki/Law_of_large_numbers) on your averages.

In my experience, Celerons are not very fast for servers. (especially with only 512 MB of ram).

Whenever you run into high memory usage (taring or untaring backups for example), your server will slow down drastically if it goes into the swap.

Start to add accounts, you'll get a good feel at what type of customers you're getting and what your requirements are. Asking here, isn't going to help you much, because we're all getting different types of customers.

A great example of how hard it is to answer this question...

I have a dual opteron running one site at about max capacity and I have the exact same server running just over 1k sites right next to it not even close to resource capacity.

Of course the one site pays more then all of the sites combined on the other server. It's all a matter of what your putting on the server(s).