Analysis and Construction of Functional Regenerating Codes with Uncoded Repair for Distributed Storage Systems

TL;DR

This paper introduces functional minimum storage regenerating (FMSR) codes that enable uncoded repair in distributed storage, reducing repair bandwidth and disk reads without requiring surviving nodes to encode data.

Contribution

It proves the existence of FMSR codes under double-fault tolerance, provides a deterministic construction, and validates their practical benefits through implementation and evaluation.

Findings

FMSR codes enable uncoded repair without encoding at surviving nodes.

Deterministic FMSR code construction accelerates repair processes.

Implementation in a cloud storage system demonstrates practical advantages.

Abstract

Modern distributed storage systems apply redundancy coding techniques to stored data. One form of redundancy is based on regenerating codes, which can minimize the repair bandwidth, i.e., the amount of data transferred when repairing a failed storage node. Existing regenerating codes mainly require surviving storage nodes encode data during repair. In this paper, we study functional minimum storage regenerating (FMSR) codes, which enable uncoded repair without the encoding requirement in surviving nodes, while preserving the minimum repair bandwidth guarantees and also minimizing disk reads. Under double-fault tolerance settings, we formally prove the existence of FMSR codes, and provide a deterministic FMSR code construction that can significantly speed up the repair process. We further implement and evaluate our deterministic FMSR codes to show the benefits. Our work is built atop a practical cloud storage system that implements FMSR codes, and we provide theoretical validation to justify the practicality of FMSR codes.