The new platforms-as-a-service (PaaS) cloud offerings from vendors such as Amazon Web Services AWS, Microsoft Azure and Google App Engine offer extremely detailed control of charging. Indeed this charging model is often part of the attraction of cloud. It enables organisations to pay only for the services they consume, whether these services are storage, processing power or server virtualisation.
However, such cost models also mean that IT architecture design decisions can have a dramatic impact on the total cost of ownership for a system. As a result, decisions that could previously be considered inconsequential in determining system running costs can have significant and perhaps unexpected effects on the cost of running a system incorporating cloud services.
For example, PA Consulting Group recently worked with a public-sector client to deliver a large-scale Google App Engine implementation which needed to query large data sets calculated from source data at speed. The client had to choose between executing complex run-time queries and paying for processing power, or pre-computing large data sets and so paying for storage. Either approach was valid, but which would be more cost-effective?
To inform the decision, PA developed a model to calculate how the cost of the service changed as the user volumes increased, and then compared the impact of different architectural approaches. Our model allowed the client to compare two options, one of which was projected to cost $10,000 less per day to run within two years. The client then asked PA to develop this more cost-effective solution.
The modelling also allowed us to identify points in the growth of usage volumes at which a previously uneconomical design became the more efficient solution. Such breakpoints ranged from the obvious scenarios, such as when the client began paying for reserved rather than on-demand instances, to the less obvious and varying patterns for cost-effective integration of Google Maps overlays.
To find out more about making the most cost-effective use of cloud platforms for your organisation contact us now.