Here are just a few variables that need to be addressed up front:
The first variable has to do with performance. Factors such as uptime, transaction time, and failover recovery time should be spelled out. And there should be economic consequences for deviations. A service level agreement (SLA) can address some of those issues.
The second variable has to do with your data, specifically, where it will reside and how easy it will be for you to access it. In terms of where your data resides, different countries have different laws regarding data privacy, so it's important to know what you're getting into if your vendor parks your data offshore. As for access, federal mandates concerning e-discovery make getting at your data (all your data) and locking it down an imperative if you're involved in litigation.
The third variable has to do with what happens when the engagement ends. For instance, what if the service provider goes belly up or you have a falling out? What if you decide to go with another service provider for the same service (which is a very real possibility given increasing competitive pressure)? How easy will it be to transfer your data and business processes?
These are just a few very high-level variables that need to be made explicit before you enter into a cloud computing engagement. Your negotiations should be specific to your situation. Don't worry about pushing your cloud partner too hard on the details. After all, it's just business.When it comes to a cloud computing engagement, whether it's software-as-a-service (SaaS), infrastructure-as-a-service (IaaS), or platform-as-a-service (PaaS), the upfront is all-important. That's because there are so many variables to be accounted for during the length of the engagement, as well as at the back end, that a detailed accounting of what to expect from your service provider and your rights in the relationship is mandatory.