Given a distributed service support system S realized on a cloud (e.g., replicated data services), QoS assessment captures the SLA violations that may arise under various resource depletions and outages faced by S. The issue of less-than-100% guarantee of QoS arises due to the lax control of the underlying cloud resources and components that is typical of third-party providers. Our goal is to reason about how well the system-internal mechanisms are geared to offer a required level of service to the application. We employ computational models of S to determine the optimal feasible output and verify how close is the actual behavior of S to this 'gold-standard'. Case studies from diverse application domains are described to corroborate our assessment methodology.
['Kaliappa Ravindran', 'Arun Adiththan', 'Michael Iannelli', 'Mohammad Rabby']
External Assessment of QoS Provisioning in Distributed Cloud Services