A Class of MSR Codes for Clustered Distributed Storage

Abstract

Clustered distributed storage models real data centers where intra-and cross-cluster repair bandwidths are different. In this paper, exact-repair minimum-storage-regenerating (MSR) codes achieving capacity of clustered distributed storage are designed. Focus is given on two cases: epsilon = 0 and epsilon = 1/(n-k), where epsilon is the ratio of the available cross-and intra-cluster repair bandwidths, n is the total number of distributed nodes and k is the number of contact nodes in data retrieval. The former represents the scenario where cross-cluster communication is not allowed, while the latter corresponds to the case of minimum cross-cluster bandwidth allowing minimum storage overhead. For the epsilon = 0 case, two types of locally repairable codes are proven to achieve the MSR point. As for epsilon = 1/(n - k), MDS codes achieve the MSR points for n = Lk, where L is the number of clusters.