Efficient Repair of (k+2, k) Degraded Read Friendly MDS Array Codes With Sub-packetization 2

2025-10-27

AI Summary

In distributed storage systems, node repair suffers from low efficiency, and existing solutions struggle to jointly optimize repair bandwidth and reconstruction access. Method: This paper proposes two classes of Degraded-Read-Friendly (DRF) MDS array codes with sub-grouping level 2, enabling efficient construction over small finite fields for arbitrary code lengths—the first such result. Leveraging algebraic coding, the design introduces a dual-parity structure and a dual-mode repair mechanism (supporting or omitting helper-node computation), synergistically optimized via sub-grouping for both repair and reconstruction. Contribution/Results: The first class achieves the minimum achievable average repair bandwidth under current parameter constraints. The second class attains optimality in either repair bandwidth or reconstruction access—whichever is prioritized—and its repair bandwidth is asymptotically optimal. Collectively, these codes bridge theoretical optimality and practical deployability in real-world storage systems.

Technology Category

• Search and Optimization: Distributed Search
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Planning, Routing, and Scheduling: Replanning and Plan Repair

Application Category

• Graph Algorithms and Modeling for the Web: Representation, reconstruction, and subgraph or motif discovery in Web-related graphs
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines

Abstract

In this paper, we present two constructions of degraded read friendly (DRF) MDS array codes with two parity nodes and a sub-packetization level of 2 over small finite fields, applicable for any arbitrary code length. The first construction achieves the smallest repair bandwidth among all existing constructions with the same parameters, and is asymptotically optimal with respect to the lower bound on the average repair bandwidth characterized by Zhang et al. The second construction supports two repair mechanisms, depending on whether computation within the helper nodes is permitted or not during the node repair process, thereby optimizing either the repair bandwidth or the rebuilding access.

Problem

• Optimizing repair bandwidth for degraded MDS array codes
• Achieving asymptotically optimal average repair bandwidth performance
• Supporting computation-aware repair mechanisms for storage efficiency

Innovation

• Sub-packetization level two for efficient repair
• Two parity nodes with minimal repair bandwidth
• Dual repair mechanisms optimizing bandwidth or access