Data migration in the scalable storage cloud

Data migration within storage cloud is complicated due to the necessity of scaling the cloud. Dividing migration is proposed to speed up scaling. Migration is divided into scaling and residual migration. The problem of data migration within storage cloud is defined as a multi-criterion optimization problem of data relocation plan. The main criterion of the optimization is scaling speed. The second criterion is residual migration speed. In general, the problem of data migration is NP-hard. Polynomial time approximation algorithm is presented in this article. The another result of this work is a prove of optimality algorithm by the first criterion.