Cooperative repair based on tree structure for multiple failures in distributed storage systems with regenerating codes

Regenerating codes have been proposed to achieve an optimal trade-off curve between the amount of storage space and the network traffic for repair. However, existing repair schemes based on regenerating codes are inadequate to meet the requirements of small network traffic cost and high efficiency when repairing multiple failures. In this paper, we propose a cooperative repair scheme based on tree structure for multiple failures with regenerating codes, called CTREE. For generality, we propose a two-layer repair framework to support both repairs for single and multiple failures. For high repair efficiency, a parallel tree-structured data transmission technique is proposed to organize the data transmissions between the providers and newcomers. For small network network traffic cost, a core-based data exchange technique is proposed to organize the data exchanges between the coordinator and the other newcomers. To evaluate the performance of CTREE, we conduct experiments on both 30 physical and 200 virtual servers. Numerical analysis and extensive experiments confirm that CTREE can support both single and multiple failure repairs, significantly reduces the network traffic cost and improves the repair efficiency compared with the state-of-the-art approaches under various parameter settings.