The requirements from Chapter 3, The Design Factors, are very specific about the maximum number of virtual machines that can be run on a host. This simplifies the scale-up or scale-out design decision. The following are a couple of other possible design requirements to work through to demonstrate the impact that scaling up and scaling out will have on resources:

• What if a requirement was to virtualize the environment using three hosts? What resources would be required for each host? If there are 100 virtual machines, how many will be impacted during a host hardware failure?
• What if the requirement was that each host should be configured with resources to support no more than 10 virtual machines? How will that change the number of resources required for each host? If there are 100 virtual machines, how many will be impacted during a host hardware failure?