A Generic Construction for All Parameters in Minimum Storage Regenerating Codes

Abstract

Minimum-Storage Regenerating (MSR) codes have become superior alternatives to traditional erasure codes as they can provide optimal repair bandwidth while the reliability and the storage overhead are still optimal. So far, the state-of-the-art MSR codes mainly focus on connecting to all the remaining nodes to repair a single failure. Since the recovery latency may be bottlenecked by the time taken to retrieve the slowest or straggling block, it is however impractical to have the highest connectivity in MSR codes. In this paper, we introduce a generic construction for all parameters in MSR codes, which allows for bandwidth-efficient repair of a single data node failure with an arbitrary (but fixed) number of accessed nodes d. Our method provides explicit and generic encoding and repairing processes, and such codes were not previously known to exist. When d = n - 1, we show that our codes are not inferior to the other MSR codes and retain the same recovery optimality. Furthermore, the arbitrary number of d allows our codes to adapt to the late binding strategy to avoid stragglers (overloaded sites) for efficient recovery performance. As a result, our codes outperform both traditional erasure codes and the state-of-the-art MSR codes on the aspect of the response time when the system is subjected to an imbalanced load.