On non-uniform flower codes

Abstract

For a Distributed Storage System (DSS), the�Fractional Repetition�(FR) code is a class in which replicas of encoded data packets are stored on distributed chunk servers, where the encoding is done using the Maximum Distance Separable (MDS) code. The FR codes allow for the exact uncoded repair with minimum repair bandwidth. In this paper, FR codes (called Flower codes) are constructed using finite binary sequences. It is shown that, for any FR code, there exists a Flower code and therefore Flower code is the general framework to construct FR code with uniform as well as non-uniform parameters. The condition for universally good Flower code is calculated on such sequences. For some sequences, the universally good Flower codes and Locally Repairable Flower codes are explored. In addition, conditions for equivalent Flower codes and dual Flower codes are also investigated in this paper. Some families of Flower codes with non-uniform parameters are obtained such that, from those families, Flowers code with uniform parameters are optimal FR codes in the literature. It is shown that any FR code is a Flower code and some known FR codes are obtained as the special cases of Flower codes using sequences.