Repairing Multiple Failures with Coordinated and Adaptive Regenerating Codes

TL;DR

This paper introduces coordinated and adaptive regenerating codes that enable efficient simultaneous repair of multiple failures in distributed storage, improving repair flexibility and cost management.

Contribution

It presents novel coordinated and adaptive regenerating codes that support multiple failure repairs and parameter adaptation, extending the capabilities of existing regenerating codes.

Findings

Coordinated regenerating codes support simultaneous multiple device repairs.

Adaptive regenerating codes allow parameter adjustments during repair.

Lazy repairs reduce disk-related costs but not network bandwidth.

Abstract

Erasure correcting codes are widely used to ensure data persistence in distributed storage systems. This paper addresses the simultaneous repair of multiple failures in such codes. We go beyond existing work (i.e., regenerating codes by Dimakis et al.) by describing (i) coordinated regenerating codes (also known as cooperative regenerating codes) which support the simultaneous repair of multiple devices, and (ii) adaptive regenerating codes which allow adapting the parameters at each repair. Similarly to regenerating codes by Dimakis et al., these codes achieve the optimal tradeoff between storage and the repair bandwidth. Based on these extended regenerating codes, we study the impact of lazy repairs applied to regenerating codes and conclude that lazy repairs cannot reduce the costs in term of network bandwidth but allow reducing the disk-related costs (disk bandwidth and disk I/O).