Capacity Planning

To conclude, here are some useful things to keep in mind:

Inform yourself about the way IIS 5.0 works, so that you can track down trouble before it starts.
Remember the old rule of thumb: Computing needs rise to fill available resources in about six months, on average. You should be planning for at least six months out.
Whatever you get, even if it seems sufficient now, is going to require upgrading sooner or later; in today’s climate, it’s more likely to be sooner than later.
Don’t skimp on RAM. A server computer running IIS 5.0 should have a minimum of 128 MB of RAM, though you can get by with less if you can tolerate some impact on performance. It’s probably impossible to set up a server with “too much” RAM.
If you are concerned with the speed and reliability of disk access, consider caching controllers and “RAID 01” arrays. However, a caching controller is pointless unless lots of your clients tend to request the same information.
Be extremely aware of security issues. For more information, see Security in this book.