Consolidation of multi-tier workloads with performance and reliability constraints

Server consolidation leverages hardware virtualization to reduce the operational cost of data centers through the intelligent placement of existing workloads. This work proposes a consolidation model which considers power, performance and reliability aspects simultaneously. There are two main innovative contributions in the model, focused on performance and reliability requirements. The first contribution is the possibility to guarantee average response time constraints for multi-tier workloads. The second contribution is the possibility to model active/active clusters of servers, with enough spare capacity on the fail-over servers to manage the load of the failed ones. At the heart of the proposal is a non-linear optimization model that has been linearized using two different and exact techniques. Moreover, a heuristic method that allows for the fast computation of near optimal solutions has been developed and validated.