Nines are Not Enough: Meaningful Metrics for Clouds
Nines are Not Enough: Meaningful Metrics for Clouds
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九还不够：对云有意义的指标
DOI：
10.1145/3317550.3321432
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
J. Wilkes
中科院分区：
文献类型：
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作者：
J. Mogul;J. Wilkes
云计算客户希望得到强有力的、可理解的承诺（服务水平目标或SLO），即他们的应用程序将可靠地运行并具有足够的性能，但云计算提供商不想提供这些承诺，因为在面对任意客户行为和共享资源的统计复用所带来的隐藏交互时，这些承诺在技术上很难满足。现有的云SLO更关心的是防范极端情况，而不是定义正常行为。这种紧张关系和其他紧张关系使得SLO令人惊讶地难以定义。我们发现，这个问题有一些相似之处的挑战，应用统计数据进行决策的基础上采样数据。我们认为，一个互利的服务水平期望（SLEs）和客户行为期望（CBES）改善了许多问题，今天的SLOs明确分担客户和服务提供商之间的风险。
Cloud customers want strong, understandable promises (Service Level Objectives, or SLOs) that their applications will run reliably and with adequate performance, but cloud providers don't want to offer them, because they are technically hard to meet in the face of arbitrary customer behavior and the hidden interactions brought about by statistical multiplexing of shared resources. Existing cloud SLOs are more concerned with defending against corner cases than defining normal behavior. This and other tensions make SLOs surprisingly hard to define. We show that this problem shares some similarities with the challenges of applying statistics to make decisions based on sampled data. We argue that a mutually beneficial set of Service Level Expectations (SLEs) and Customer Behavior Expectations (CBEs) ameliorates many of the problems of today's SLOs by explicitly sharing risk between customer and service provider.