Capacity Planning

Capacity Planning Issues

The Internet commerce site has special requirements that affect capacity planning in specific ways. These involve performance, security, and availability:

The site, because of its “real-time” nature, must be designed to handle the maximum number of concurrent customer connections that can be expected, with a good safety margin so that it can smoothly handle spikes in usage.
The site designer must implement a high level of security and potentially some form of data encryption. This can easily add 15 to 20 percent in system resource overhead to each transaction.
It is possible for the site’s performance to be constrained by a downstream resource. For example, the Web server that handles catalog content may be able to handle 200 transactions per second; but if the sales tax or credit card components can only handle 50 transactions per second, there is a potential for a serious bottleneck to develop. It is crucial for site designers and administrators to be aware of these external constraints where they occur.