Distributed Storage Codes Based on Double- Layered Piggybacking Framework

Piggybacking codes are a class of distributed storage codes adopted in distributed storage systems, which received much attention in recent years. Two novel piggybacking constructions based on the double-layered piggybacking framework are proposed. They can reduce the repair bandwidth of both the systematic nodes and the parity nodes efficiently. The average repair bandwidth ratio for the two constructions approaches to zero asymptotically as the number of systematic nodes and parity nodes tends to infinity. Compared with other piggybacking codes, the two proposed double-layered piggybacking codes, especially the second one, not only require less design constraints, but also obtain the optimal comprehensive repair efficiency, which further save the amount of data read and downloaded.