Practical Software Measurement

Not Just for Software: How Estimation and Sizing Can Help You Plan a Successful IT Infrastructure Project

Estimation and Sizing for Infrastructure

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While creating technology is about solving everyday problems, the act of creating technology is about solving design problems. This applies to any type of technology project, regardless of its purpose or size. Organizations must put as much thought and consideration into the design of their underlying IT infrastructures as they do in the design of their software projects. Both require careful sizing, estimation and planning.

Of course, installing, configuring and testing IT infrastructure is different than developing a piece of software. A typical IT infrastructure project could include:

  • Server room buildout (clean power, fire prevention, disaster recovery, cabling, etc.)
  • Network connectivity (local and wide area network)
  • Installation of computer server hardware (can be physical or virtual)
  • Configuration of system software on the servers (operating system, database, email server, web server, security template, etc.)
  • Configuration of computer desktops, laptops, smart phones. peripherals and other Internet of Things (IoT) devices 

Together, the hardware and software formulate a truly complex system where all of the parts are interconnected.

Developing this complex infrastructure is not a trivial process. It requires a lot more work and effort than simply procuring the hardware to make the infrastructure a reality – and the bigger the data center, the more time and effort is necessary to set up things properly.

Fortunately, just as with software development, parametric sizing and estimation can help ensure your plans are realistic so that you can deliver a quality IT infrastructure on a predictable budget and schedule.

Let’s take a look at what this involves.

Scope out the size of the IT infrastructure.

When scoping the size of software functionality, the project team identifies countable artifacts that describe the functionality (e.g. number of agile user stories, number of user cases, number of function points, etc.). These artifacts quantify what functionality will be required and are a key input to a parametric estimation tool (e.g. SLIM).

The idea behind infrastructure sizing is the same, but the approach is a bit different. Instead of sizing the scope of software functionality, you must scope out your entire infrastructure. This involves considering the number of users in your organization and the overall business requirements your organization’s infrastructure will need to support. Then, you’ll need to develop an IT infrastructure requirements list and supporting design that meets these needs while ensuring that all of the various facets of the infrastructure work in sync with each other.

Make a list of all hardware components.

Just like you probably wouldn’t go grocery shopping without a list, nor should you begin developing an IT infrastructure without considering all of the different components that will be necessary to make the infrastructure a reality. Make a list of all of the servers, mobile devices, workstations, and other components you’ll need to create a fully functioning and reliable data center. This will give you a better understanding of exactly what you’ll need to complete the infrastructure.

Don’t forget the server and application software.

Infrastructures aren’t just hardware; they include operating systems, email and database servers, Enterprise Resource Planning and Customer Relationship Management software, and other virtual tools. Be sure to also take into consideration any virtual solutions that will be needed to manage the underlying hardware infrastructure.

Estimate the effort and duration to design, configure, test, and transition.

Once you’ve quantified the size of the required IT infrastructure, you can enter it into a parametric estimation tool (e.g. SLIM) to estimate what it will take, in terms of effort, cost and schedule, to design, configure, test and transition. To ensure you are making realistic productivity assumptions, it helps to configure your parametric estimation tool with historical data from previous IT infrastructure projects.

If you do the above, you are well on your way to creating more realistic plans for IT infrastructure projects. If you’d like to learn more, I encourage you to read this excellent white paper, which provides more detail on how you scope out the size of IT infrastructure. Though the paper was written more than 10 years ago, the methodology is still sound and can easily be applied to today’s virtual hardware. You can learn more about parametric estimation tools like SLIM here. Our research has shown they work equally well in estimating any human design effort, not just software.

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Estimation Sizing Infrastructure