Consistent hashing has played an indispensable role in cloud infrastructure, although its load balancing performance is not necessarily perfect. Consistent hashing has long remained the most widely used method despite many methods being proposed to improve load balancing because these methods trade off load balancing against consistency, memory usage, lookup performance, and/or fault-tolerance. This article presents Structured Allocation-based Consistent Hashing (SACH), a cloud-optimized consistent hashing algorithm that overcomes the trade-offs by taking advantage of the characteristics of cloud environments: scaling management and auto-healing. Since scaling can be distinguished from failures, SACH applies two different algorithms to update hashing functions: a fast-update algorithm for unmanaged backend failures to satisfy fault-tolerance with quick response and a slow-update algorithm for managed scaling. Hashing functions are initialized or slow-updated considering the characteristics of the fast-update algorithm to satisfy load balancing and the other properties as far as the number of failed backends is kept small by auto-healing. The experimental results show that SACH outperforms existing algorithms in each aspect. SACH will improve the load balancing of cloud infrastructure components, where the trade-offs have prevented the renewal of hashing functions.

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基于结构化分配的一致性哈希和改进的云基础架构平衡

一致性哈希在云基础架构中起着不可或缺的作用，尽管其负载平衡性能不一定是完美的。尽管提出了许多改善负载平衡的方法，但是一致性哈希一直是使用最广泛的方法，因为这些方法在负载平衡与一致性，内存使用，查找性能和/或容错性之间进行权衡。本文介绍了基于结构化分配的一致性哈希（SACH），这是一种云优化的一致性哈希算法，该算法通过利用云环境的特性（扩展管理和自动修复）克服了折衷方案。由于可以区分扩展与失败，因此SACH应用了两种不同的算法来更新哈希函数：一种用于非托管后端故障的快速更新算法，以快速响应来满足容错能力；以及一种用于托管扩展的慢速更新算法。哈希函数的初始化或缓慢更新要考虑到快速更新算法的特性，以满足负载平衡和其他属性，只要通过自动修复将失败的后端数量保持在很小的水平即可。实验结果表明，SACH在各个方面均优于现有算法。SACH将改善云基础架构组件的负载平衡，在这种平衡中，权衡阻止了哈希功能的更新。哈希函数的初始化或缓慢更新要考虑到快速更新算法的特性，以满足负载平衡和其他属性，只要通过自动修复将失败的后端数量保持在很小的水平即可。实验结果表明，SACH在各个方面均优于现有算法。SACH将改善云基础架构组件的负载平衡，在这种平衡中，权衡阻止了哈希功能的更新。哈希函数的初始化或缓慢更新要考虑到快速更新算法的特性，以满足负载平衡和其他属性，只要通过自动修复将失败的后端数量保持在很小的水平即可。实验结果表明，SACH在各个方面均优于现有算法。SACH将改善云基础架构组件的负载平衡，在这种平衡中，权衡阻止了哈希功能的更新。