Capacity Planning

Determining Your Installation’s Requirements

If you are building a new server site, you must develop a sense of its requirements in order to decide what hardware and software to acquire. Consider what the site will be required to do, and what services it will provide. Will it:

Serve a known set of clients on an intranet or intranet/extranet connection to the Web? (That is, can you predict the number of clients with any accuracy, and is it possible to get a good sense of their usage behavior?)
Allow people to download and possibly upload files with File Transfer Protocol (FTP) service?
Provide e-mail with Simple Mail Transfer Protocol (SMTP) service?
Provide news with Network News Transfer Protocol (NNTP) service, which is typically coupled with large storage requirements?
Allow clients to access a database or large index using SQL or other query language, or with Indexing Service? Allowing this kind of access will entail large storage requirements for the database itself.
Perform transactions using Microsoft® Component Services, which is processor-intensive?
Provide name service?
Function as a domain controller?
Provide file and print service?

As discussed earlier, there are also page construction and Web application issues. Will your server or servers primarily send out static HTML pages? (Doing so involves memory for caching files.) Will the server run scripts in ASP pages (ASP service involves queuelength optimization issues as well as cache space), ISAPI, and CGI applications? (ASP, ISAPI, and CGI are all processor-intensive, and CGI applications are inefficient under Windows 2000 Server.) Do you need to run some of your pages out of process, for testing or other purposes? (This is also processor-intensive.) In addition, you must figure in the constraints of budget, facilities, and staffing.

If you can find a site with requirements that are similar to yours and examine its history, you may be able to discover (and possibly avoid) some of these potential pitfalls.

If you are working with an existing site, you can monitor the site server and log its performance. This will give you a sense of current conditions and will let you see how well the existing hardware and software are meeting current user needs. (See Monitoring and Tuning Your Server in this book.)