Capacity Planning

There are two main issues involved in setting up a transactional site:

The site will almost always rely on a database, which gathers customer information. But usually the database cannot be replicated in the same way that content can be striped. As a result, adding Web servers as the site grows will increase the traffic load on the database server.
As the amount of data and traffic grows with an increasing number of customers, additional components need to be implemented to deal with customer connection issues. Some of these issues include ODBC time-outs, WINS errors, and server failures. In fact, connection issues can encompass anything that keeps a customer from putting information into the database or retrieving information from it. The additional overhead of these components has effects on the overall performance of the site, which must be taken into account as the site expands.