Two-layer Locally Repairable Codes for Distributed Storage Systems

TL;DR

This paper introduces a two-layer locally repairable code structure for distributed storage systems that optimizes data recovery and repair efficiency through layered encoding with MDS codes.

Contribution

It presents a novel two-layer encoding scheme combining MDS codes for optimal minimum distance and local repair, with scalable finite field construction.

Findings

Achieves optimal minimum distance for LRCs in DSS

Supports efficient local repair and degraded reads

Constructed over finite fields with size linear in number of nodes

Abstract

In this paper, we propose locally repairable codes (LRCs) with optimal minimum distance for distributed storage systems (DSS). A two-layer encoding structure is employed to ensure data reconstruction and the designated repair locality. The data is first encoded in the first layer by any existing maximum distance separable (MDS) codes, and then the encoded symbols are divided into non-overlapping groups and encoded by an MDS array code in the second layer. The encoding in the second layer provides enough redundancy for local repair, while the overall code performs recovery of the data based on redundancy from both layers. Our codes can be constructed over a finite field with size growing linearly with the total number of nodes in the DSS, and facilitate efficient degraded reads.