1. A method for operating a system comprising multiple resources, said method comprising: identifying for each resource a set of one or more failure risks for that resource, using a computer system; combining for each identified failure risk a likelihood of failure and an expected resolution time to provide a risk weight for the identified failure risk; accumulating for each resource the risk weights for each failure risk for that resource to provide an accumulated risk weight for the resource; and provisioning workload across the multiple resources based on the accumulated risk weights for each resource, by allocating higher priority tasks to resources with lower accumulated risk weights.