Edge computing, as a new computing paradigm, brings cloud computing’s computing and storage capacities to network edge for providing low latency services for users. The networked edge servers in a specific area constitute edge storage systems (ESSs), where popular data can be stored to serve the users in the area. The novel ESSs raise many new opportunities as well as unprecedented challenges. Most existing studies of ESSs focus on the storage of data replicas in the system to ensure low data retrieval latency for users. However, replica-based edge storage strategies can easily incur high storage costs. It is not cost-effective to store massive replicas of large-size data, especially those that do not require real-time access at the edge, e.g., system upgrade files, popular app installation files, videos in online games. It may not even be possible due to the constrained storage resources on edge servers. In this article, we make the first attempt to investigate the use of erasure codes in cost-effective data storage at the edge. The focus is to find the optimal strategy for placing coded data blocks on the edge servers in an ESS, aiming to minimize the storage cost while serving all the users in the system. We first model this novel Erasure Coding based Edge Data Placement (EC-EDP) problem as an integer linear programming problem and prove its $\mathcal {NP}$ -hardness. Then, we propose an optimal approach named EC-EDP-O based on integer programming. Another approximation algorithm named EC-EDP-V is proposed to address the high computation complexity of large-scale EC-EDP scenarios efficiently. The extensive experimental results demonstrate that EC-EDP-O and EC-EDP-V can save an average of 68.58% (and up to 81.16% in large-scale scenarios) storage cost compared with replica-based storage approaches.

中文翻译：

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使用纠删码在边缘存储系统中进行经济高效的数据放置

边缘计算作为一种新的计算范式，将云计算的计算和存储能力带到网络边缘，为用户提供低时延的服务。特定区域联网的边缘服务器构成边缘存储系统(ESS)，其中可以存储流行的数据以服务于该地区的用户。新颖的 ESS 带来了许多新机遇，也带来了前所未有的挑战。大多数现有的 ESS 研究都集中在系统中数据副本的存储，以确保用户的数据检索延迟低。然而，基于副本的边缘存储策略很容易产生高昂的存储成本。存储大量数据的海量副本并不划算，尤其是那些不需要在边缘实时访问的数据，例如系统升级文件、热门应用程序安装文件、在线游戏中的视频。由于边缘服务器上的存储资源受限，这甚至可能是不可能的。在本文中，我们首次尝试调查纠删码在边缘的经济高效数据存储中的使用。重点是找到将编码数据块放置在 ESS 中的边缘服务器上的最佳策略，旨在最大限度地降低存储成本，同时为系统中的所有用户提供服务。我们首先为这部小说建模基于擦除编码的边缘数据放置(EC-EDP) 问题作为整数线性规划问题并证明其$\数学{NP}$ -硬度。然后，我们提出了一种基于整数规划的名为 EC-EDP-O 的最优方法。提出了另一种名为 EC-EDP-V 的近似算法，以有效解决大规模 EC-EDP 场景的高计算复杂性。广泛的实验结果表明，与基于副本的存储方法相比，EC-EDP-O 和 EC-EDP-V 可以平均节省 68.58%（在大规模场景中高达 81.16%）的存储成本。