As a kind of erasure code, piggybacking has been applied in practice since it can significantly reduce the repair bandwidth of distributed storage systems. Currently, several efficient piggybacking designs have been proposed. In this paper, we propose a more efficient “one-to-one” piggybacking design (OOP) to further reduce the repair bandwidth. Different from the existing piggybacking designs, OOP adopts a simple encoding principle that one parity node only piggybacks symbols from one substripe. Particularly, OOP takes into account the efficient repair of systematic nodes and parity nodes simultaneously. It is shown that for OOP design, the optimal number of substripes is $(\sqrt {r-1}+r-1)$ , the average repair bandwidth ratio of systematic nodes can be as low as $\frac {2\sqrt {r-1}+1}{2\sqrt {r-1}+r}$ , and the average repair bandwidth ratio of parity nodes reaches $\left({\frac {\sqrt {r-1}+1}{r}+\frac {(r-1)^{2}-\sqrt {(r-1)^{3}}}{rk}}\right)$ . In contrast to the existing piggybacking designs, OOP can further reduce the repair bandwidth of both system nodes and parity nodes.

中文翻译：

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分布式存储系统的高效一对一捎带设计

作为一种纠删码，piggybacking可以显着降低分布式存储系统的修复带宽，在实践中得到了应用。目前，已经提出了几种有效的搭载设计。在本文中，我们提出了一种更有效的“一对一”搭载设计（OOP），以进一步降低修复带宽。与现有的搭载设计不同，OOP采用了一种简单的编码原则，即一个奇偶校验节点只搭载来自一个子带的符号。特别是OOP同时兼顾了系统节点和奇偶校验节点的高效修复。结果表明，对于 OOP 设计，最佳子带数为 $(\sqrt {r-1}+r-1)$ ，系统节点的平均修复带宽比可以低至 $\frac {2\sqrt {r-1}+1}{2\sqrt {r-1}+r}$ ，奇偶校验节点的平均修复带宽比达到 $\left({\frac {\sqrt {r-1}+1}{r}+\frac {(r-1)^{2}-\sqrt {(r-1)^{3}}}{ rk}}\right)$ . 与现有的搭载设计相比，OOP 可以进一步降低系统节点和奇偶校验节点的修复带宽。