Heterogeneity-Aware Codes With Uncoded Repair for Distributed Storage Systems

Abstract

In practical large-scale distributed storage systems, node failures are unavoidable. It is therefore desirable to quickly recreate the failed nodes in order to maintain the system integrity. In this letter, we consider a family of erasure codes that provide uncoded repair, where the failed node is regenerated by transfer of data without extra arithmetic operations. We introduce flexible fractional repetition (FFR) code, of which the coding scheme is a concatenation of an outer MDS code and an inner repetition code. Our proposed codes are applicable to the heterogeneous network environment where node storage capacities and packet repetition degrees vary in a wide range. We present explicit constructions of FFR codes by utilizing combinatorial designs. We further propose a heuristic code construction. Evaluation results show that FFR codes outperform regenerating codes in node repair efficiency.

Construction of Fractional Repetition Codes with Variable Parameters for Distributed Storage Systems

“…It is known that regular FR codes are good for load balancing [15] while irregular FR codes are suitable for heterogeneous networks [21]. Though various irregular FR codes have been proposed, for example, in [17,18,20,21], we focus on introducing existing regular FR codes related to our proposed construction. Also, we consider only the regular FR codes for 3 ≤ ρ ≤ α and β = 1.…”

“…FR codes can be seen as a variant of exact MBR codes and they aim to minimize disk I/O as well as network bandwidth for repair. Various construction methods for FR codes are proposed using graphs, design theory, algebraic structures, and so on [14][15][16][17][18][19]. Note that the existing construction methods result in FR codes with quite restricted code parameter values, which will be discussed in Section 2.…”

Load-Balanced Fractional Repetition Codes

“…Fractional repetition codes have been well-studied since they were introduced in 2010; see [4,13,19,[23][24][25][26]. FR codes use the minimum possible network bandwidth and disk access (the amount of data read by the surviving nodes in order to be sent) to repair node failures.…”

Construction of New Fractional Repetition Codes from Relative Difference Sets with λ=1

“…In [16], the existence of FR codes for each parameter set is shown by algorithm-based search, and some examples for each parameter set are provided. Many kinds of FR codes have been constructed mostly based on algebraic structures, combinatorial designs and graph theory [15,[17][18][19][20][21][22]. In [15], Steiner systems are used as a class of (v, (v − 1)/(k − 1), k) FR codes with β = 1 under the existence of Steiner system S(2, k, v).…”

“…It is also noted that the proposed FR codes can be seen as a part of the general class of FR code constructed from group divisible design (GDD) [19,20]. However, the contribution of this work is to explicitly provide three construction methods directly based on relative difference sets and m-sequences, propose a modification method from the three constructions to generate a new class of FR codes and analyze them in detail, while the basic idea and general framework are given in [19,20]. This paper is organized as follows.…”