The need for system administrators—especially Linux sys admins—to do performance management has returned with a vengeance. Why? The cloud. Resource consumption in the cloud is all about run now, pay later (AKA 'chargeback' in mainframe-ese). This talk will show you how performance models can help to find the most cost-effective deployment of your applications on Amazon Web Services (AWS). The same technique should be transferable to other cloud services. Presented at Rocky Mountain CMG, Denver, Colorado.