Capacity planning checklist

Network capacity planning can be a tricky endeavor for managers and administrators who are not in possession of a crystal ball. There are no shortcuts to capacity planning, but this tip presents five steps to help simplify the task.

Since most administrators are not in possession of a crystal ball, network capacity planning can be a very tricky...

endeavor. Unfortunately, there are no shortcuts to capacity planning. In fact, I could easily write an entire book on the subject. As I can't possibly tell you everything there is to know about capacity planning within the space of an article, I want to share five steps that will help you to be more successful with your capacity planning.

1. Meet with executive management

Perhaps the most important step in capacity planning is to have occasional meetings with your company's executive staff. The reason this is so important is that growth is not usually linear. Over the years, I've seen countless situations in which administrators assume that because the company grew by 10% last year, it's going to grow by 10% next year, and they use that projection for capacity planning. In the real world, though, things are rarely this simple.

Anyone who watches the stock market knows the economy tends to fluctuate. It's these very fluctuations that often dictate whether -- or how much -- a company is going to grow over a given period of time. That's why it's so important to discuss the company's outlook with the executive management staff. It's their job to understand what the market is doing and how that is going to affect the company's growth. In most cases, the executive management staff should be able to give you a more accurate growth projection than you could make on your own.

2. How well is the existing hardware meeting the company's current needs?

For capacity planning, the next thing I recommend looking at is how well the existing hardware is meeting the company's current needs. This is important because it gives you a starting point on which to base purchasing decisions.

For example, if your hardware is currently performing very slowly, and you are anticipating even a small amount of short-term growth in the company, then purchasing more-capable hardware needs to be a very high priority. After all, if your hardware isn't handling today's workload very well, then how well is it going to handle the increased workload tomorrow? If, on the other hand, your existing hardware is not being utilized to anywhere near its full potential, then it may be perfectly adequate to handle the company's anticipated growth. In either situation, you cannot make an intelligent purchasing decision unless you know how well your existing hardware is meeting today's needs.

3. What will be your future needs?

The next question that you need to answer is what will the future needs be? At first, it may seem that the company's future needs are the same as its future growth. Nothing could be further from the truth, however. If you are looking only at the company's future growth, what you are really looking at is how well the existing infrastructure, servers, and applications will hold up to an increased number of users.

Future needs are different, though, and have more to do with the way the company's business may change. For example, if the company were to take on a new client, there could be a special application that would need to run on your servers in order to service the client. Even if you don't anticipate running any new applications, new versions of existing applications are typically released every couple of years. In most cases, these new versions of existing applications tend to require higher-end hardware than the previous version did. These are the types of things that you need to take into account when planning for future needs.

4. Can anything be consolidated?

I'm sure that some administrators would argue with me on this point, but I have always believed that when you address the issue of capacity planning, it is also a good time to look for possible opportunities to consolidate servers.

Having more servers means you're spending more money. I'm not talking just about licensing costs, although that is also an issue. Each server on your network represents a substantial investment. You get the initial cost of the hardware and the ongoing costs of maintenance for that server. If it looks as though your capacity planning is going to lead to additional hardware purchases, it sometimes makes sense to spend a little bit extra and buy servers that are each powerful enough to take the place of two or more existing servers.

Of course, you must keep in mind that server consolidation is not always a good thing. When it comes to your infrastructure, it is important to have some redundancy for file tolerant reasons. For example, it might be perfectly acceptable to consolidate an internal DNS server and a domain controller onto the same physical server, but you probably would not want to perform a consolidation that reduced the number of domain controllers or the number of DNS servers on your network.

5. Will the existing infrastructure support the anticipated growth?

The fifth issue you need to address is whether or not your existing infrastructure will support the anticipated growth. For example, suppose that you learn in a meeting with the executive management staff that the company is about to hire 100 additional employees. With this knowledge, it would be relatively easy to look at your existing file servers, Exchange Servers and other application servers to make sure that they have enough memory and disk space to accommodate the new employees.

What isn't quite so cut and dried is whether or not the network infrastructure can support the new employees comfortably. For example, are your DNS servers being overworked, or can they comfortably handle the extra workload that 100 extra users will place on them? What about network bandwidth? Will that existing 100 Mbps connection between the users in the servers be sufficient, or are you going to need to upgrade to a gigabit connection? These are just some of the issues that you must consider in regard to your network infrastructure.


As you can see, capacity planning is not a simple matter. Although it is impossible for me to give a thorough explanation of capacity planning within the limits of this tip, I sincerely hope that this checklist will help you to think about the steps you need to take in order to plan effectively for your network's future growth.

About the Author: Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server and IIS. Brien has served as CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. As a freelance technical writer, he has written for technology companies that include Microsoft, CNET, ZDNet, TechTarget, MSD2D, and Relevant Technologies. You can visit Brien's personal Web site at

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