A Repair-Efficient Piggybacking Design With Small Number of Substripes

With the rapid growth of data scale and limitation on bandwidth in networks, coding scheme in distributed storage system is becoming the research hotspot. The piggybacking framework can solve the problem of high repair bandwidth of traditional MDS codes in distributed storage systems, while satisfying the properties of maximum-distance-separability (MDS) and high code rate which can guarantee the high storage efficiency. Several piggybacking designs have been proposed mainly aiming at the repair of systematic nodes. For the repair of parity nodes, these designs either adopt the traditional MDS code decoding or reduce the repair bandwidth by multiplying the number of substripes, which is not ideal in practice. In this paper, based on an single instance of repair efficiency piggybacking scheme, some specially designed simple finite field additions are introduced to encode parity symbols. The new design scheme is called NREPB. It can effectively reduce the repair bandwidth of parity nodes while ensuring no side-effect on the repair of systematic nodes. And the number of substripes in NREPB remains small, which is important in practical applications.