Enterprises often approach the decision of migrating to the public cloud with the wrong mindset: They primarily consider the infrastructure they need to replace, and not the workloads they will actually run.

But solution providers should lead enterprises through a different economic analysis when they make long-term IT investments, one focused on application behavior and usage requirements, Stanton Jones, director and emerging technology analyst at technology advisory firm Information Services Group, told ITBestofBreed.

A thorough understanding of application and business needs is essential when determining the cost benefits of different hosting environments, a point illustrated by ISG's latest Cloud Comparison Index, which compared on-premises infrastructure against standard Linux distributions, Red Hat Enterprise Linux and Windows Server on the four largest public clouds.

"The message floating around the market is that cloud is always cheaper, and it's absolutely not the case," Jones said. "What we are encouraging providers to do is to take an application-centric view to cloud, not an infrastructure-centric view."

The ISG index could help solution providers wrap their heads around the true costs of cloud usage so customers can optimize their IT spending while ensuring that applications remain in the proper operating environments.

ISG started performing that kind of analysis earlier this year because of "a tsunami of demand from our clients asking for help in figuring out if cloud really is always cheaper," Jones said. Those clients include many Fortune 100 companies.

It's a dilemma that is currently causing "a huge amount of consternation in organizations," he said.

The index was intentionally restrained to the narrow use cases of workloads running on either "standard" Linux, Red Hat's Linux or Windows, he said.

Unlike the mostly uniform costs for on-premises configurations — which ISG concluded from a proprietary benchmarking database — the cost for public cloud varies tremendously by how much it's used.

For that reason, solution providers should help their customers create a usage profile that will help determine the overall business case for the public cloud and total cost of ownership, Jones said. Those can't be achieved by looking at infrastructure alone.