Characterizing caching workload of a large commercial Content Delivery Network
Characterizing caching workload of a large commercial Content Delivery Network
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DOI：
10.1109/infocom.2016.7524379
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发表时间：
2016-04
期刊：
影响因子：
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通讯作者：
M. Shafiq;Amir R. Khakpour;A. Liu
中科院分区：
文献类型：
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作者：
M. Shafiq;Amir R. Khakpour;A. Liu
内容分发网络（CDN）已经成为通过互联网分发内容的主导机制。尽管它们很重要，但据我们所知，在以前的文献中缺乏对CDN缓存性能的大规模分析。CDN同时为许多内容发布商提供服务，因此具有独特的工作负载特征;它通常处理来自多个内容发布商的超大内容量和高度内容多样性。CDN还具有独特的性能指标;除了命中率之外，CDN还需要最大限度地减少缓存服务器上的网络和磁盘负载。在本文中，我们提出了在一个大型的商业CDN缓存工作负载的测量和分析。使用来自四个地理分布的CDN缓存服务器的详细日志，我们分析了超过6亿个内容请求，占流量超过1.3 PB。我们从广泛的角度分析CDN工作负载，包括请求组成、大小、流行度和时间动态。使用真实日志，我们还评估了缓存替换算法，包括基于CDN工作负载分析设计的两个增强功能：N-hit和内容感知缓存。结果表明，这些增强实现了缓存命中率，磁盘负载和源流量方面的性能大幅提高。
Content Delivery Networks (CDNs) have emerged as a dominant mechanism to deliver content over the Internet. Despite their importance, to our best knowledge, large-scale analysis of CDN cache performance is lacking in prior literature. A CDN serves many content publishers simultaneously and thus has unique workload characteristics; it typically deals with extremely large content volume and high content diversity from multiple content publishers. CDNs also have unique performance metrics; other than hit ratio, CDNs also need to minimize network and disk load on cache servers. In this paper, we present measurement and analysis of caching workload at a large commercial CDN. Using detailed logs from four geographically distributed CDN cache servers, we analyze over 600 million content requests accounting for more than 1.3 petabytes worth of traffic. We analyze CDN workload from a wide range of perspectives, including request composition, size, popularity, and temporal dynamics. Using real-world logs, we also evaluate cache replacement algorithms, including two enhancements designed based on our CDN workload analysis: N-hit and content-aware caching. The results show that these enhancements achieve substantial performance gains in terms of cache hit ratio, disk load, and origin traffic volume.