Graftage Coding for Distributed Storage Systems
Jiayi Rui, Qin Huang, Zulin Wang · IEEE Transactions on Information Theory · 2021
To achieve various tradeoffs between storage and repair bandwidth, this article proposes to construct exact repair codes by grafting two codesC1andC2. By replacing certain nonzero entries in the generator matrix ofC1by zero, the repair bandwidth of the resulting grafting part decreases. However, it may no longer keep the maximum-distance-separable (MDS) property. As a result, the grafted codeC2takes these nonzero entries into account such that the entire graftage code can keep the MDS property. The relationship between the bandwidth reduction ofC1and the file size ofC2is derived to optimize graftage codes. Our analysis indicates that these graftage codes may provide better tradeoffs than space-sharing.