Code constructions for multi-node exact repair in distributed storage

Abstract

We study the problem of centralized exact repair of multiple failures in distributed storage. We present constructions that achieve a new set of interior points under exact repair. The constructions build upon the layered code construction by Tian et al., designed for exact repair of single failure. We firstly improve upon the layered construction for general system parameters. Then, we extend the improved construction to support the repair of multiple failures, with varying number of helpers. In particular, for some parameters, we prove the optimality of one point in terms of the storage size and the repair bandwidth for multiple erasures. Finally, considering minimum bandwidth cooperative repair (MBCR) codes as centralized repair codes, we determine explicitly the best achievable region obtained by space-sharing among all known points, including the MBCR point.

Storage and repair bandwidth tradeoff for heterogeneous cluster distributed storage systems

“…In [17,24], the authors proposed algorithms for the cluster DSS model corresponding to the above two steps under the assumption that the newcomer connects to all the alive nodes, namely, d = n − 1. However, this assumption cannot be used to analyse the cases with multiple node failures, which is also frequent in realistic storage systems [20,32]. Thus we investigate more flexible situations in [22,28], where the applicability of the algorithms are proved under more general assumption…”