A Class of MSR Codes for Clustered Distributed Storage

TL;DR

This paper designs exact-repair MSR codes tailored for clustered distributed storage systems, addressing scenarios with no cross-cluster communication and minimal cross-cluster bandwidth, providing explicit schemes and proving optimality.

Contribution

It introduces new MSR code constructions for clustered storage with different bandwidth constraints, including explicit schemes for specific cluster configurations.

Findings

MSR codes achieved for zero cross-cluster bandwidth

Explicit MSR coding scheme for two-cluster systems with n=2k

Locally repairable codes proven to reach MSR point in certain cases

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 that is possible under the minimum storage overhead constraint. For the $\epsilon=0$ case, two types of locally repairable codes are proven to achieve the MSR point. As for $\epsilon=1/(n-k)$, an explicit MSR coding scheme is suggested for the two-cluster situation under the specific condition of $n = 2k$.