Optimal VM migration planning for data centers

Various network optimization and management goals in cloud data centers can be achieved by re-mapping VMs to the substrate servers. Live VM migration is used to implement such re-mapping by moving VMs from the initial servers to the target ones. For efficiency and usability considerations, these migration tasks are expected to be completed as soon as possible, which can be achieved by planning multiple VMs to be migrated simultaneously. However, the available resources of computation and bandwidth limits the number of VMs that can be migrated at the same time. Besides, the available resources change with the progress of migration process, which makes VM migration planning a challenge problem. Considering both resources constraints and the dependence between the migration plan and the total migration time, in this paper, we investigate the problem of virtual machine migration planning to minimize the total migration time. We formulate VM migration planning as an optimization problem considering both computation and bandwidth constraints. Our formulation is based on a step-by-step migration scheme, where multiple VMs can be migrated simultaneously as long as the resource constraints are satisfied. The solution of the optimization problem outputs the migration plan which achieves the minimum time to finish the migration task. Moreover, we verify the effectiveness of the optimal migration plan through extensive simulations and comparison with the best algorithm in existing works.