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Colloquium – Alexandru Uta
August 28 @ 10:00 am - 11:00 am
Vrije Universiteit Amsterdam
August 28, 2019
lecture – 10:00am
Host: Rob Ricci
Big Data in the Wild:The Effects of Cloud Network Performance Variability
Performance variability has been acknowledged as a problem for over a decade by cloud practitioners and performance engineers. Yet, our survey of top systems conferences reveals that the research community regularly disregards variability when running experiments in the cloud. Focusing on networks, we assess the impact of variability on big-data cloud-based workloads. Using real-world variability traces from the gigabit-era, we show that not only does network variability incur (variable) slowdowns of up to 16X, but also unreliable experimentation: few repetitions run high risks of reporting unreliable numbers; 30–50 experiments are needed in practice to achieve tight confidence intervals. We characterize the network variability of post-gigabit networks and show that, even though commercial cloud providers implement mechanisms for quality-of-service enforcement, variability still occurs. Consequently, big-data workloads still suffer from significant variable slowdowns, and lack of predictability, even when applying state-of-the-art experimentation.