Workflows are the de facto standard for managing business processes and allow businesses to automate interactions between business locations and partners residing anywhere on the planet. This, however, requires the workflows to be executed in a dynamic environment, where device and communication failures occur frequently, making availability a key concern. In this work, we propose the replicated execution of workflows for ensuring availability in the presence of failures. The replicated execution has to yield the same result as a non-replicated execution of that workflow. Thus, we formally define Single-Execution-Equivalence and present a replication scheme that adheres to this definition. We implement a proof-of-concept using an open-source workflow engine for demonstrating the compatibility with current workflow technology. Our evaluations on Amazon EC2, OpenStack, and PlanetLab show that workflow replication ensures availability while being scalable and incurring low overhead in terms of execution time.

中文翻译：

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高可用性工作流引擎的复制方案

工作流是用于管理业务流程的事实上的标准，并允许业务自动化业务位置与地球上任何地方的合作伙伴之间的交互。但是，这需要在动态环境中执行工作流，在动态环境中，设备和通信故障经常发生，这使可用性成为关键问题。在这项工作中，我们提出工作流的重复执行，以确保出现故障时的可用性。复制执行必须产生与该工作流程的非复制执行相同的结果。因此，我们正式定义了Single-Execution-Equivalence，并提出了遵循此定义的复制方案。我们使用开源工作流引擎实施概念验证，以证明与当前工作流技术的兼容性。