Dissecting persistent instability of web service: A joint perspective of server schedule dynamics and path latency

摘要

Web service has become very popular because of its portal role like searching and video streaming, as well as its convenience of building. Complex communication and computation infrastructures behind modern web service are brought forward to satisfy diverse requirements, such as content delivery networks and clouds. However, no longitudinal studies about web serving pattern dynamics have been performed. To investigate the joint communication and computation patterns, we conducted a 1-year fine-grained measurement on world and China top 500 websites. Specifically, we examined path latency (perspective of communication) combined with hosting server dynamics (perspective of computation) from a longitudinal view of end user. Our result shows that persistent latency instability could exist with 2 contributors. One is persistent diurnal pattern, which exhibits significant daily latency discrepancy from 60 to 360ms and can exist up to nearly 120days out of 1year. Another factor is dynamic server schedule. We design metrics and estimate to what extent server dynamics takes on over a long-term period and how it correlates with end-to-end latency. Further, we take a look at topological and geographical factors of server changes that affect path latency instability. The result shows that world and China top sites have different spatial dominators in terms of server change-related latency instability.