  This paper describes two tools that aim to support decision making during the
migration of IT systems to the cloud. The first is a modeling tool that
produces cost estimates of using public IaaS clouds. The tool enables IT
architects to model their applications, data and infrastructure requirements in
addition to their computational resource usage patterns. The tool can be used
to compare the cost of different cloud providers, deployment options and usage
scenarios. The second tool is a spreadsheet that outlines the benefits and
risks of using IaaS clouds from an enterprise perspective; this tool provides a
starting point for risk assessment. Two case studies were used to evaluate the
tools. The tools were useful as they informed decision makers about the costs,
benefits and risks of using the cloud.
