Common assumptions relate to power, space, and cooling. A common example of an assumption that an architect may make is as follows:

• There is sufficient power, cooling, and floor/rack space available in the data center to support both the existing and consolidated environment during the migration

While working through the physical design, the power, cooling, and space requirements will need to be identified and the assumptions validated. A goal of this project is to consolidate the existing physical servers. The overall need for power, cooling, and space will be reduced once the project is complete, but enough of these resources need to be available to support both the existing physical environment and the new consolidated environment during the consolidation process.

Referring to our mock design, a requirement was identified based on the discovery information to provide N+2 redundancy:

This requirement was defined based on the following discovery information:

• A 1-hour maintenance window each month for application and hardware maintenance. Hardware maintenance is currently a challenge. Since hardware and application maintenance cannot be performed at the same time, the maintenance window does not typically provide the time that's necessary to perform both application and hardware maintenance.
• Application uptime and accessibility is very important.

What assumption may have been made when defining this requirement?

An assumption was made based on the importance of application uptime and accessibility that there should be sufficient resources to provide redundancy not only during normal operations, but also in the event of a host failure. When a host is unavailable due to maintenance being performed, the following approach should be adopted:

• Resources should be provided to support a host failure during both normal and host maintenance operations

The following requirements relating to growth were also defined:

• The business expects to add 50 new customers over the next year
• Support growth over the next 5 years

An expected, the growth of 50 customers over the next year was identified, but the design is expected to support growth over the next 5 years. To create this requirement, an assumption was made that growth would be the same over years two through five, resulting in the documentation of the following assumption: growth is calculated based on the addition of 50 new customers each year over the next 5 years.

The company may have a forecast for growth that exceeds this. If this assumption is incorrect, the design may not meet the defined requirement.