Bandwidth Cost of Code Conversions in the Split Regime
Bandwidth Cost of Code Conversions in the Split Regime
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DOI：
10.48550/arxiv.2205.06793
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发表时间：
2022-05
期刊：
影响因子：
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通讯作者：
Francisco Maturana;K. V. Rashmi
中科院分区：
文献类型：
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作者：
Francisco Maturana;K. V. Rashmi
分布式存储系统必须长时间存储大量数据。为了避免设备故障导致的数据丢失，使用[n， k]擦除码将k个数据符号编码为包含n个符号的码字，这些码字存储在不同的设备上。但是，设备故障率在数据的整个生命周期中都会发生变化，根据这些变化调整n和k可以节省大量的存储空间。码转换是将初始[nI， kI]码的多个码字转换为解码为同一组数据符号的最终[nF， kF]码字的过程。在本文中，我们研究转换带宽，定义为转换过程中节点之间传输的数据总量。特别地，我们考虑了初始码和最终码都是MDS的情况，并且单个初始码字被分成几个最终码字（对于整数λF≥2，kI = λF kF），称为分裂状态。我们推导了在分裂状态下转换带宽的下界，并提出了显著降低转换带宽的结构，并且对某些参数是最优的。本文的扩展版本可在[1]获得。
Distributed storage systems must store large amounts of data over long periods of time. To avoid data loss due to device failures, an [n, k] erasure code is used to encode k data symbols into a codeword of n symbols that are stored across different devices. However, device failure rates change throughout the life of the data, and tuning n and k according to these changes has been shown to save significant storage space. Code conversion is the process of converting multiple codewords of an initial [nI, kI] code into codewords of a final [nF, kF] code that decode to the same set of data symbols. In this paper, we study conversion bandwidth, defined as the total amount of data transferred between nodes during conversion. In particular, we consider the case where the initial and final codes are MDS and a single initial codeword is split into several final codewords (kI = λF kF for integer λF ≥ 2), called the split regime. We derive lower bounds on the conversion bandwidth in the split regime and propose constructions that significantly reduce conversion bandwidth and are optimal for certain parameters.An extended version of this paper is available at [1].