Live migration in Greenplum database based on SDN via improved gray wolf optimization algorithm

Data migration has become one of the key technologies for load balance and high performance services in the distributed systems. In past years, the data migration researches focused on several factors including resource utilization, data quality or security improvement and migration time reduction, whereas the investigation on how to provide continuous system service during the data migration process has not attracted enough attention. In this paper, the migration operation cost and the user service quality are both weighted in the proposed migration scheme so as to guarantee a continuous high quality of user service during the data migration procedure. First, a cost-based migration model is built. Based on this model, the migration operation among the nodes of the data cluster is formulated as an optimization problem which targets to search for the optimal execution sequence. Then, an improved grey wolf optimization algorithm (IGWO) is proposed to search for the optimized migration solutions. In addition, to guarantee the high quality service for some critical user requests, the bandwidth reserved for the migration operations is dynamically managed through the on-demand programming of SDN (Software Defined Network) controller. We conducted the experiments on the Greenplum database, and the results showed the effectiveness of the proposed migration scheme.